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BOOKS BY
WILLIAM EMERSON RITTER

The Higher Usefulness of Science.

The Probable Infinity of Nature
AND Life.

The Unity of the Organism, or
the Organismal Conception of
Life. Illustrated.

The Unity of the Organic Species,
with Special Reference to the
Human Species.

War, Science and Civilization.

An Organismal Conception of
Consciousness,

RICHARD G. BADGER, publisher, BOSTON

r

THE UNITY OF THE
ORGANISM

OR
THE ORGANISMAL CONCEPTION OF LIFE

BY

William Emerson Ritter

Director of the Scripps Institution for

Biological Research of the University

of California, La Jolla

California

TWO VOLUMES
VOLUME ONE

ILLUSTRATED

BOSTON

RICHARD G. BADGER

THE GORHAM PRESS

Copyright, Idli), by Richard G. Badger

All Rights Reserved

This work contains the text of the hook:
**An Organismal Theory of Consciousness" •

Made in the United States of America

The Gorham Press, Boston, U. S. A.

TO MY WIFE

MARY BENNETT RITTER

MY SEVEREST CRITIC AND
BEST HELPER

PREFACE

'THHE right of any book to live must be determined finally
-*■ by what is on its pages. Nevertheless, when the author
of a scientific book undertakes such a task as I have under-
taken in this one, his natural and acquired fitness for carry-
ing out his project ought to count in some measure toward
the determination. An attempt to speak with some degree
of originality and autliority on subjects so remote from one
another as are the chemistry of organisms, heredity, human
consciousness, and the nature of knowledge, would be some-
what audacious even if made by an author of secure reputa-
tion as an investigator in one or more of these fields. When,
however, the attempt is that of a complete stranger to all
the fields, as thus judged, the attempt is no longer entitled
to be called "somewhat audacious." It is audacious out and
out, and if defensible at all is defensible in spite of its
audacity. But the very nature of the task I have attempted
seems to require me to contend that while it is audacious it
is yet not impossible, and to point out something of my own
qualifications for performing it.

Such professional fitness as I have rests primarily on my
being a general zoologist in the proper sense ; that is, a
student of the phenomena of the animal world without ex-
clusion of any aspect of that world from professional in-
terest and some measure of professional attention. These
facts of my vocation, and of my conception of the nature of
that vocation are crucial for the quality not only of this
book but all my general writings.

If once one becomes as deeply convinced as I am of both
the fundamental unity and the fundamental diversity of all

ix

X Preface

nature; if, in other words, he becomes convinced that the
whole of nature is, indeed, and not in mere expression, a
system, the conviction will carry with it the perception that
all specialized natural knowledge is absolutely dependent for
meaning on the relation it has to its appropriate larger body
of knowledge. Either analytic knowledge or synthetic knowl-
edge of nature would be wholly void of meaning were it to
be completely wrenched from the other. Most men of
science perhaps, and most philosophers probably, would ad-
mit that this is true as an abstract proposition. But what
about its truth when brought to the test of particular cases?

The audacity of my enterprise really consists in my at-
tempting to act according to this general truth in a par-
ticular case — the case, that is, of the phenomena of animal
life. I have gone on the assumption that knowledge of
animal chemistry, for example, at one extreme, and of
human consciousness at the other, would be simple blanks as
to meaning but for the relation of the two knowledges to
each other and to still more general knowledge of animal
life. Could we imagine a chimpanzee possessed of as much
laboratory knowledge of organic chemistry as an Emil
Fischer, that knowledge would be really meaningless were
the creature's mind that of a chimpanzee in all other re-
spects.

A systematic defense of a conception of zoology based on
a general theory of natural knowledge such as this, can not,
of course, be thought of in a preface. Indeed, such a con-
ception can not be fully justified by any argument merely
for it. The justification must be found largely in a worked-
out application of the conception itself. In other words, the
very fabric of this book must be the chief justification
sought. All I can wish to do in a preface is to mention
certain subsidiary ideas and principles that have been spe-
cially influential in determining the plans of my undertaking;
and certain methods and disciplinary preparations and pres-

Preface xi

ent conditions that have been specially useful in carrying
them out.

Probably no one zoological item has influenced me more
than the perception that the evolutionary interpretation of
man does not mean that man's derivation from the lower
animals made him something that is now not animal. It
means that man is just as much an animal to-day as were
his prehuman ancestors. The truth is exactly stated by
saying that when the transformation took place by which
man came into existence that transformation was from a
lower to a higher stage of animal life. The actual problem,
consequently, of man's nature is not as to what man is in
opposition to animals, but as to the kind, or species of ani-
mal he is.

With the distinction here made once fully grasped comes
the revelation tliat man is an object of zoological research
and treatment no less certainly than is a horse, a fish, a
lobster, or an amoeba. But since man's highest, that is his
psychical or spiritual attributes are the ones most decisive
of his hvnd, it is these attributes which make him particularly
interesting, zoologically speaking — just as, for example, it
is the attributes of a horse as a horse, and not as an animal
generally that elicits our particular interest in the horse.
Zoology rightly understood is preeminent among all the
sciences as the science of particulars. This important truth
seems to have been first appreciated by Aristotle; and the
fact that one of the most fundamental differences between
him and his teacher, Plato, concerned the doctrine of Par-
ticulars as opposed to that of Universals, is probably con-
nected closely with Aristotle's great interest in and attention
to zoology. I have not seen any reference to this surmise
by writers on Aristotle and his philosophy, yet it appears
to me highly significant.

From these perceptions relative to the nature of man and
the science of animal life, it follows that when the zoological

xii Preface

study of man is undertaken — when the general zoologist
becomes for the time being an anthropological zoologist —
all the best tested and most approved methods of that
science are taxed to their uttermost, simply because of the
great complexity of the species under examination. Now it
is absolutely beyond question, I believe, that of the methods
employed in the biological sciences, none are more important,
especially for the study of man, than those of description
and classification with their necessary accompaniment, com-
parison. The essay The Place of Description, Depnition a7ul
Classification in Philosophical Biology in my little book. The
Higher Usefulness of Science, treats of this subject some-
what at length. But that to which I attach mucli more
importance is that almost everything contained in the pres-
ent book, except the heart of Chapter 24, I regard as an
embodiment of the fundamental principles of descriptive and
classificatory biology as these principles are established by
modern research.

It seems to me I am privileged to claim that no reader of
this and other general writings of mine is in position to pass
judgment on them, except, of course, as touching trustworthi-
ness of observation and statement, and of dependability of
authorities cited, without having considered conscientiously
my position as to method. For instance, am I right or wrong
in holding (see the above mentioned essay) that far the
larger part of what is usually called explanation in dealing
with the phenomena of nature is really partial or tentative
or hypothetical description and classification .^^ What justi-
fication and scope are there for my contention that the motto
"neglect nothing," which has long done good service in taxo-
nomic research based on morphology, must be extended to
all departments of structural and functional biology.'^ What
grounding and applicability are there for my distinction
between synoi)tic and analytic description, and synoptic and
analytic classification? Not until one has come to see that

Preface xiii

questions of this sort arc necessary consequences of progress
in information about, and interpretation of living nature,
is he able to appreciate fully what I mean by chemical and
psychological zoology. Formal biochemistry and animal
psychology, that is, the chemistry and the psychology of
laboratories devoted to these subjects, are to my zoological
eyes really quite Incidental and partial and crude, albeit
immensely important. Let one once feel the full weight of
the inductive evidence favorable to the hypothesis that every
organism whatever performs every jot and tittle of its ac-
tivities through chemico-physical agencies, and he must at
tlie same time feel the meagerness and crudity, compara-
tively speaking, of even the fullest and best laboratory
knowledge of those agencies by which he himself, let us say,
operates as he carries through and expresses in words an
argument like that now occupying us.

The absolute trustworthiness of the main findings of
laboratory biochemistry and its incalculably great impor-
tance, but at the same time its great imperfection as com-
pared with natural biochemistry, are what especially impress
me as I bring my best powers to bear on the deepest, most
distinctive problems of anthropological zoology ; problems,
in other words, of tlie human animal.

Sucli an attitude toward biochemistry will, I hope, be
recognized even by biochemists as calculated to induce at
least a receptive frame of mind toward knowledge in this
domain. It should be one Important qualification for "read-
ing up" In the domain. But certain it is that something
more than a receptive mind is essential to enable one disci-
plined in one field of science to be a successful gleaner of
ripened fruit in another field. It Is not true that all the
domains of natural knowledge, highly developed as they now
are, are enough alike to make training In any one an ade-
quate preparation for acquiring second hand knowledge in
every other. At least a background of systematic instruc-

XIV Preface

tion in a particular science is requisite to make a liiglilj
successful reader even in that science.

So far, then, as I am able to pass upon my own quali-
fication for making such use as I have made of biochemistry,
it is a question of whether I have a sufficient ground-work
of formal training to make me a safe chooser among authori-
ties and estimater of the significance of their results.

Although my chemical practice was limited to three years,
one of these as a student assistant, so much did I live in the
laboratories during that period, that even to-day the open-
ing of a book or journal on chemistry seems to fill my nose
with foul though pleasantly reminiscent odors and to en-
crust and stain my fingers with diverse corrosives — all of
which may mean that I was more a musser in chemicals than
a real student of chemistry. Nevertheless I verily believe
the experience enabled me to be a more intelligent reader of
chemical writings.

As for the science of mind, I am obliged to own that I
have never spent a day in an experimental laboratory of
either animal behavior or human psychology. But I own
also that for this I am not regretful if such defect of train-
ing be an essential condition of escape from the narrowing
of interest in and conception of "behavior" which has at-
tended later work in this field. I do not believe, however, that
this is the only way of such escape. Zoologists must realize
before long, I am quite sure, that laboratory experimentation
in animal behavior can be only a rather minor agent for the
task of understanding the psychical life of the animal world
as a whole.

This leads to the remark I wish to make about the discus-
sion of psychic integration in the last chapters of this book.
One of the most important things accomplished by that dis-
cussion is, I estimate, the calling attention to the tendency
of instinctive activity to excessiveness over the actual needs
served by the activity. Why has this truth (for there can

Preface xv

be no question that it is a truth) not received more atten-
tion from modern beliavior specialists? There are probably
several reasons, but a particularly influential one seems to be
the fact that the very purpose, and the method of experimen-
tation involving the idea of control by the student are
such as to encourage overlooking the phenomena, and to
obscure their significance even if they are noticed.

Unorthodoxly enough from the standpoint of present
school psychology, my entrance into this realm was from
the side of the nature and the theory of knowledge. And so
far as my explorations in the realm have gone, two men,
Aristotle and the late Professor G. H. Howison have influ-
enced me so vitally that I must say a few words on the
subject.

For many years Aristotle was two distinct persons to me,
so far as any real influence upon my thinking was con-
cerned. On the one hand there was Aristotle the metaphysi-
cian to whom I had been formally introduced by Howison in
a private outside-of-hours University course (which with
great generosity he had given me), the medium of the in-
troduction being the De Anvma. On the other hand was
Aristotle the zoologist, acquaintance with whom was at first
picked up in the usual naturalist fashion, but which had
later ripened into intimac}^, as I like to characterize it, by
our common interest in marine zoology, his good description
of the anatomy of a tunicate being a special passport to my
affection. It would hardly be an exaggeration to say that
all my philosophizing in biology has aimed at fusing these
two Aristotles into one. I do not mean that this has been
my conscious and express aim. It has been so only instinc-
tively, or intuitively, or "at heart," or by "working hy-
pothesis," or by whatever expression one chooses for it.
And here comes the part played by Professor Howison : As
I take a bird's eye view now of what is set forth in this and
other general writings of mine, and contemplate the whole in

xvi Preface

the light of the preface to Howison's book, The Limits of
Evolution, and then look reflectively back over my thirty
years of contact with him and his teachings, most of it inci-
dental and fitful, but some of it rather close, a few influences
of his, sonie positive and some negative, stand out sharply
indeed. The positive influences I mention first. No other
influence contributed so much to my belief in the power of
reason ; that is, in a substratum of truth to the idealistic
philosophy. Again no other influence contributed more to
my belief in persons — in the power of personality; that is,
in a substratum of truth to the Howisonian philosophy of
personal idealism.

A statement of the negative influence coming from the
same source takes us back to Aristotle. In the preface to
The Limits of Evolution Howison writes, referring to his
own theory of Personal Idealism, "The character of the
present theory, relatively to Aristotle, is to be found in its
attempt to carry out the individualistic tendencies in Arls-
totelianism to a conclusion consistently coherent." This
statement I could almost adopt word for word as a charac-
terization of the purpose that has animated all my general
thinking and writing. Yet how profoundly does the out-
come of my eff*orts diff^er from that resulting from Profes-
sor Howison's efforts ! And here is the kernel of my present
remarks : In commending to me the De Anima of Aristotle
and generously undertaking to guide me through it, as a
response to my appeal for help toward clarifying my mind
concerning the deeper, the philosophical meaning of bio-
logical evolution, my greatly learned and much esteemed
teacher had a purpose, I am now quite sure, that is impos-
sible of realization. That purpose was to show that Aris-
totle failed in his eff'ort to recognize a "real world" through
combining "ideal form" w^ith "real matter," because for him
a real world was more fundamentally a sense-experienceable
world than is actually the case. As I labored through the

Preface xvii

De Anima I recall that I was disturbed by the rather cavalier
fashion in which we disposed of those portions of the work
which treat of reproduction, nutrition and growth, and espe-
cially the portions dealing with the senses. At the stage
of scientific development I was then in, I knew little or noth-
ing of Aristotle's biological writings, and Howison referred
to them only in the most cursory way, if indeed he men-
tioned them at all. Certain it is he did nothing to arouse
my interest in them, or to indicate that he regarded them
as specially significant in connection with such important
views of Aristotle's as those on the relation of Body and
Soul. The question which now seems to me indispensable
for grasping the essense of the Aristotelian psychology and
philosophy that, namely, of why Aristotle was so greatly in-
terested in zoology, and devoted so much time to its study,
never came up during the course, I am quite sure. In sci-
ence and philosophy as in everything else, the character of
one's interests is a surer index to his general views and atti-
tude than is anything he can express verbally. There may
be ambiguity and error in Aristotle's theory of "synthetic
Entelechy." This theory may, probably does, "beset," as
Howison remarks, "all individual existence both behind and
before," thereby implying some theoretical derogation from
the real nature of personality. But over against this error
and ambiguity stands indubitable proof of Aristotle's prac-
tical faith in the Particular, the Individual, that proof be-
ing the vast labor he expended in learning and interpreting
the life of the animal world. The chief philosophic signifi-
cance of Aristotle's zoological works is not in any informa-
tion or theories they contain but in the fact that he pro-
duced them at all, since, as mentioned above, zoology is pre-
eminent as the science of particulars, and his doctrine of
Particulars as opposed to Universals was very close to the
heart of his whole philosophic system.

This prepares for my final remark about the influence upon

xviii Preface

my thinking of Professor Howison and the idealistic philoso-
phy generally. That philosophic Idealism, no matter of
what variety, contains elements that are fundamentally er-
roneous seems to me to be proved more conclusively by its
inadequacy for understanding the world in its entirety than
by any particular errors of fact or reasoning which it can
be shown to contain. Were all men philosophical idealists,
there would be no natural science, merely because in the
domain of learning men will not choose as their primary
life work what they fully believe to be of secondary im-
portance.

Fallaciousness or inconclusiveness of argument never de-
terred me half as much from embracing Professor Howison's
teachings in their entirety as did his usually dignified but
always-present presumption of professional self-superiority
over all his colleagues who did not come under the, to him,
sacred segis of Philosophy. The reason why sincere humility
and the spirit of democracy are alien to all forms of idealis-
tic philosophy becomes clear once one attains a world view
which truly strives to include, but makes no pretense of hav-
ing already included, the whole world wholly in that view.

There remains the pleasant though difficult task of men-
tioning the few among my numberless obligations which are
so personal and weighty that to leave them unacknowledged
would be to brand me as ungrateful, more conspicuously than
I can endure.

First as to those persons and conditions which, during the
last ten years, have relieved me from the routine duties of a
University teacher, and also from most of the exactions
customarily attaching to an administrative post even in an
institution of scientific research, and have given me a status
the central purpose of which is scientific work. Whatever
be the quality and final significance of my life-work, could
these, I ask myself, have reached as high a level as they
have reached had I not come into my present position? Al-

Preface xix

most certainly not, must be the answer. And beyond a doubt
the raising of the question involves principles of organization
for scientific research that lift it high above mere personal
concern.

No faith of mine is greater because none is rooted more
deeply in my scientific philosophy, than that in the ultimate
triumph of popular, that is of democratic principles in all
aspects of civilization. Indeed the facts — not the theories —
of organic unity and integration which have dominated all
my later work are the foundation of this faith. Whether
my particular hypotheses and theories of organismalism suc-
ceed or fail, there still are the raw data on which they rest.
These can not fail. If success does not crown my efforts in
handling the data it will crown those of others who shall
come after me. And when the principles for which I contend
shall have worked themselves more fully into the fabric of
civilization, the organizational, the administrative, and the
scientific policies aimed at in the Scripps Institution for Bio-
logical Research of the University of California will be
recognized as fundamentally sound. I will be specific here
to the extent of mentioning the policy of providing a special
business management for such institutions.

Although my indebtedness to my professional co-workers
and official associates of the Zoological Department and the
]\Iuseum of Vertebrate Zoology at Berkeley, Professors C. A.
Kofoid, S. J. Holmes, and Dr. Joseph Grinnell, is indicated
by special references in the body of this book, I should be
sorry to have these references taken to indicate the full ex-
tent of my obligation to them, or to indicate that these are
the only members of those departments to whom I am in-
debted.

It would be a source of keen regret to me, too, should my
single short reference to two of my biological associates on
the staff of the Scripps Institution, Mr. E. L. Michael and
Dr. C, O. Esterly, be taken a-s the full measure of what I

XX Preface

owe to them. I hope that my reference to their work, brief
though it is, will be recognized as indicative of the high im-
portance I attach to what they have done and are doing.

But what about my indebtedness to professional associates
here in the home group of whose work no mention is made
in my text? How subtle and far-reaching and innumerable
are the influences which bear upon one from his daily co-
workers ! For example, by what unit of measurement could
be gauged the effects on my treatment of heredity, which have
come from my perpetual contact with the work of Dr. F. B.
Sumner and Mr. H. H. Collins ? But these men would prob-
ably resent the ascription to them of responsibility for my
main conclusions in this field. Again, not many "environ-
mental factors" have been more determinative of my present
feelings (I hardly dare call them views) relative to various
problems in geo-physics, and relative to quantitative meth-
ods in natural science, than have Dr. G. F. McEwen and his
oceanographic work. Yet I hesitate even to mention this
fact lest some one be led thereby to hold Dr. McEwen ac-
countable for crudities, actual or implied, I may manifest
in these domains.

Nor are my indebtednesses confined to the narrow circle
of my immediately professional and official co-workers. In-
deed I am keenly conscious of great debts beyond this circle.
These are so numerous and on the whole so general as to
make specification impossible, but I cannot pass by without
mentioning my debt to my long-time and much-cherished
friend. Professor G. M. Stratton, for the connnentaries on
the chapters on psychic integration made by him while this
portion of the book was in an advanced though still forma-
tive stage.

For aid in structurel labor, as it may be called, my de-
pendence upon Mr. Frank E. A. Thone, my secretary and
scientific assistant, has been varied and intimate, and of a
quality for which money can only partly pay.

Preface xxl

To Dr. Christine Essenberg, librarian and member of the
scientific staff of the Scripps Institution, I am indebted for
help on the index and glossary.

And finally, what can I say about the part played in the
creation of this and my other works by her to whom this
volume is dedicated? The extent to which her life is involved
with mine in these works only we two can know ; but the
wording of my dedication indicates something of the char-
acter of that involvement.

CONTENTS

PART I

CRITIQUE OF THE ELEMEXTALIST COXC'EPTION OF THE

ORGANISM

A. Composition of the Living Individual

CHAPTER PAGE

I. IxTROnUCTORY 1

Historic background, 1. Nature and scope of the undertak-
ing, 24.

II. The Orgaxism axd its Major Parts 30

Reflections on the problem of individuality in the living world,
30. The individual plant and its parts, 33. The individual
animal and its parts, 39.

III. The Aximal Organism axd its Germ Layers .... 45
The germ-layers, their role in development, and the germ-layer
theory, /^o. Are germ-layers developmental organs and subser-
vient to the developmental requirements of the organism? ^<5.

A negative answer to the question in the last section expected
of elementalist biology, 49. Evidence that germ-layers are
thus subservient to the organism, 49: (a) Evidence from bud
propagation in compound ascidians, 50; (6) Evidence from
bud propagation in bryozoa, 53; (c) Evidence from the regen-
eration of the lens of the amphibian eye, 57. The germ-layer
theory and the germ-plasni theory, 58. The exact mode of
involvement of the germ-plasm theory in the germ-layer
theory, 59. Weismann's studies on the origin of germ-cells in
hydroids, 60. Inconclusiveness of Weismann's results shoion
by Goette and others, 62. Weismann's erroneous conclusions
concerning the origin of sex-cells in hydroids as an example
of the effect on the observing powers of the germ-plasm type
of speculation, 66. The strongly organismal implications of
Goette's conclusions on the origin and migration of germ cells

xxiii

xxlv Contents

CHAPTER PAGE

in hydroids, 68. Remarks on the relation of germ-cells to
germ-layers and to the organism generally, 72, The relation of
ideas and observations as exemplified in the discussions of this
chapter, 74'

IV. The Organism and its Chemistry 75

Standpoint of the discussion that of the evolutionary natural-
ist, 75. The organism as a chemical laboratory, 78. Different
organisms as different chemical laboratories, 83. (a) Different
odors and flavors of animals cmd plants as distinguishable by
man, 84- {b) Differences in animal odors as distinguished by
animals themselves, 88. The ruituralist's approach to biochem-
ical problerns, 90. Some biochemical results viewed from the
naturalist's standpoint, 95. (a) Reichert and Brown's results

on hcemoglobin, 95; {b) The precipitin reaction between bloods
of different ani/mals, 99; (c) Comparative chemistry of the
sperm, of different species of fishes, 102; {d) Comparative
chemistry of milk of different species, 103; (e) Comparative
chemistry of digestive enzymes, 104; (/) Instances in general
biochemistry where interesting facts of comparative chemistry
are incidentally brought out, 106. The coalescence of natural
history and comparative biochemistry, 107. Provisional enur-
m,eration of chemico-naturalist inquiries, 109. Peculiar im-
portance to natural history of the application of physical
chemistry to the chemistry of living beings, 110: (a) Iridi-
viduation and speciation of "organic matter" ftinda/mental
biologic facts. 111; (6) Indications that variation and indi-
viduation are primarily chemical, while constancy and uni-
formity are primarily physical, 115.

V. The Organism and its Protoplasm 130

Protoplasm and mystification, 120. Responsibility for the
mystification of protoplasm, 121. Conception of animal sar-
code and plant protoplasm, as "identical stuffs," 123. Max
Schultze's actual teachings as to protoplasm and sarcode, 125:
(a) Cell nucleus distinct from protoplasm, but both nucleus
and protoplasm essential to life of cell, 126; (6) Recognized
common attributes but not identity of protoplasm in all or-
ganisms, 128. Ernst Briicke's conception of the cell as an
organism, 129. Characteiistic organization in all cells, 131.
Results of later descri/ption and classification of cell sub-

Contents xxv

CHAPTER PAGE

stances, 133: (a) Cyfojjlasni and karyoplasni cliff ereiitiated
areas of a common ba.sic substance, 135; (b) Details of cyto-
plasmic structure, 137; (c) lliree mxiin theories of the struc-
ture of 'protoplasm,, 138; (d) "No universal formula for proto-
plasmic structure," 139. Preliminary remarks on the bearing
of physical chemistry on the protojjlasm doctrine, I40. Ex-
perimental evidence for the specificity of protoplasms, 1/^3:
(a) Greater fusibility between closely related species as in
tissue mixtures and grafts, lJf3; (b) Protoplasms and not
protojylasm must be the form of the protoplasmic conception,
148.

VI. The Organism and its Cei,t.s 150

What the cell-theory is, viewed historically and substantively,
150: (a) Importance and general character of the theory,
150; (b) Various forms of the theory as currently held, 150;

(c) Statement of the theory justified by present state of
knowledge, 154- Certain inadequacies of the cell-theory, 158:
(a) As tested by embryonic development, 158; (b) As tested
by isolated cells and tissues, 167.

VII. The Cell-theory not Sufficient for Explaining the Or-

GANIS3I 179

More general inadeqiuicy of the cell-theory, 179: (a) As
tested by the regeneration and restitution of mutilated organ-
isms, 179; (b) As tested by the principle of aggregation, 182.
(c) As tested by the specificity and metaplasy of differen-
tiated cells, 186. Summary of examination of inadequacy of
cell-theory, 190. Advance t&ivard the organismal standpoint
through conception of cell reached by biochemistry p^ursued in
accordance loith the principles of physical chemistry, 191.

VIII. Further Exa3iination of the Cell-Theory . . . 198
The mosaic theory, 198. What the mosaic theory is, 198; A
modicum of truth in the mosaic theory, 198. The theory of
totipotence, 202. Experimental facts on ichich the theory
rests, 202. Balancing the account between the mosaic and
totipotence theories, 206. The "promorphology" of germ cells,
211: (a) Facts of immediate observation on which the coTir-
ception rests, 212; (6) Grounds for believing minute observ-
able specific differences between germ cells important, 214;

xxvi Contents

CHAPTER PAGE

(c) Re/lections on a 'promorpliology of germ cells beyond the
Umits of lusibility.

IX. Organisms Consisting of One Cell 237

A. Adult form and structure. Remarks on the conception

of the cell as an elementary organism, 221. Com,parison of
the structure of a single cell with that of orgatiisms composed
of many cells, 230: (a) Comparison of certain ciliates and
metazoans, 232; (6) Comparison of a radiokirian and a jelly-
fish, 235; (c) Comparison of the shell of a rhizopod and a
nautilus, 237. The unjustifiable conception that unicellular
organisms can have no tissues, 240. True organs in some pro-
tozoans, 242. A true nervous system probably present in some
protozoa, 244- -^ more critical examination of the term "or-
gan," 245. More detailed examination of the anatomy of
higher protozoa, 249. The fiction of structureless organisms,
256. The structure of bacteria, 257 : (a) Membrane and sur-
face structures, 257; (6) Structure of inner portion, 260; (c)
The question of a nucleus in bacteria, 261. Bacteria un-
doubted organisms whether ''true cells" or not, 263. B. De-
velopment, 267. False conceptions about development in pro-
tozoa, 267. Misuse of the term "ontogeny," 271. Development
of Stentor as an example of protozoan ontogeny, 272. The
terms ''embryology" and "ontogeny" inevitably used by in-
vestigators of protozoan reproduction, 277.

X. History of the Attempt to Subordinate the Protista to the

Cell-theory . . . 280

Clash between Ehrenberg and Dujardin a special case of the
conflict between organismal and elementalist conceptions, 280.
Modern opposition to the effort to Tnake protista conform to
celhdar elementalism, 286: (a) Position of Friederich Stein,
286; (b) Position of Huxley, R. Hertwig and others, 288.
General conclusions from examination of knowledge and views
as to the nature of uni- and multicellular organisms, 291.

B. The Production of Individuals by Other Individuals

XI. The Nature of Heredity and the Problem of its Mechan-
ism

Heredity the chief present-day stronghold of biological ele-

305

Contents xxvii

CHAPTER PAGE

mentalism, 305. This due particularly to discovery of inter-
dependence between adult characters and chromosomes of
germ-cells, 306. Revised conception of heredity essential to
interpreting this interdependence, 307. Unwarrantal>le tend-
ency to restrict heredity to sexual propagation, 308. Unwar-
rantable tendency to restrict heredity to adult characters, 311.
Importance of recognizing heredity as working by transforma-
tion rather than by transmission, 312. Tendency to confuse
heredity tvith causes of heredity, 313. Definition of heredity
adopted in this discussion, with remarks on its application to
the chromosome theory, Sl/f. Meaning and criterion of "mech-
anism of heredity," 322.

33fi

XII. EviDEXCE Favorable to Chromatin as Hereditary Sub-

STAXCE ..........

A. Direct Evidence. Evidence from the ontogeny of some
protozoans, 3S6. Evidence from certain cells of multicellular
organisms, 331. Evidence from spermatozoan, 333. Evidence
from pigment cells, 333. B. Indirect Evidence, 341. The
chromosomes of germ-cells in fertilization, 342. Fertilization
of the ova of one species by the sperm of another species, 344'
The connection of sex with a particular chromosome, 346. The
connection of mutations with particular chromosomes, S53.
Chromosomes and the Mendelian mode of inheritance, 356.

XIII, Kvidexce from Protozoans That Substances Other Than

Chromatin Are Physical Bases of Heredity . . . 369
Evidence from the ontogeny of various protozoans, 363: (a)
Stentor, 363; (b) What study of the ontogeny of Diplodinium
will probably discover, 370; (c) The origin of flagella, 370;
(d) Various organs of Stylonychia and Paramecium, 373; (e)
The skeleton of radiolaria, 375; (f) Openings in the central
capsule of the radiolaria, 379; (g) The shells of foraminifera,
385; (h) The clinging organs of sporozoa, 386; (i) The "di-
vision center" of Noctiluca, 390; (j) The centrosphere of pro-
tozoa generally, 394. Concluding remark on the evidence pre-
sented, 397.

LIST OF ILLUSTRATIONS

FIGURE PAGE

1. Diplodinium (After Sharp) 231

2. Hydra (After Parker and Parker) 232

3. Stylonychia Mytilus (From Hartog, After Lang) . . .233

4. Stenostoma Leucops (After Ott) 233

5. Stylonychia Mytihis (After Putter) 235

(>. Stylonychia Histrio (After Maier) 250

7. Crithidia Leptocoridis (After McCuUoch) 251

8. Crithidia Leptocoridis (After McCuUoch) 252

9. Giardia Muris (After Kofoid and Christiansen) . . . 255

10. Coryceila Armata (From Wasielewski, After Leger) . . 270

11, 12, 13, 14. Stentor Caeruleus (After Johnson) . . . 274, 275

15. Frontonia Leucas (After Tonniges) 327

l(j. Naegleria Gruberi (After Kofoid) 329

17. Spermatid of the Rat (After Duesberg) . . . . .334

18. Spermatid of Salamander (After Heidenhain) . . . .334

19. Spermatid of Snail (After Heidenhain) 336

20. Flagelliim of Euglena (After Biitschli) 371

21. Frontonia Leucas, Trichocyst (After Tonniges) . . . 374

22. Aulosphaera (After Haecker) 376

23. Aulosphaera Elegantissima (After Haecker). Detail of

Structure 377

24. Auloceros (After Haecker). Detail Section of Spine . . 377

25. Aulacantha (After Borget) 379

26. Acanthometron Pellucidum (After Moroflf and Stiasny) . . 381

27. Euglypha Alveolata, Division Stages (After Minchin) . . 384

28. Development of Pyxinia (After Leger and Dubosq) . . 387

29. Epimerite of Pileocephalus Heerii (After Lankester) . . 388

30. Epimerite of Geneiorhynchus Monnieri (After Lankester) . 388

31. Epimerite of Echinomera Hispida (After Lankester) . . 388

32. Epimerite of Beloides Firmus (After Lankester) . . . 389

33. Epimerite of Comeloides Crinitus (After Lankester) . . 389

34. Noctiluca Miliaris (After Hertwig) . ... . . .390

35. Fission Stages of Noctiluca Miliaris (After Calkins) . , 39X

XX13?

V

PART I

CRITIQUE OF THE ELEMENTALIST CONCEPTION

OF THE ORGANISM

A. Composition of the Living Individual

THE UNITY OF THE ORGANISM

Chapter I
INTRODUCTORY

Historic Background

EVERY biologist is familiar with the phrase "the organ-
ism as a whole." It occurs over and over again, par-
ticularly in later 3^ears, in written and spoken discussion
touching a wide range of subjects; and the essential idea,
expressed in different tenns, is still more common. To at-
tempt an exhaustive list of instances of the use of the
phrase or its equivalents would be profitless, but enough
must be said both at the outset and at various places
along the way to furnish a secure historic foundation for
the enterprise we are undertaking.

In its earliest infancy the science of living beings pre-
sented two theories apparently diametrically and irreconcil-
ably opposed to each other. Stating the case in familiar
terminology, according to the one the organism is explained
by the substances or elements of which it is composed, while
according to the other the substances or elements are ex-
plained by the organism. * Since it will be necessary to
refer frequently throughout our discussion to these two

* The word "explain" calls so loudly to be itself "explained" when
used in this offhand way that one reluctantly lets it go unheeded even
temporarily, but it must be passed now with this sole remark: whatever
meaning may be attached to it in one of the above propositions, exactly
the same meaning must it have in the other.

1

2 The Unity of the Organism

standpoints or theories, a short designation for each is
desirable. Historically viewed they might be spoken of as
the Aristotelian and the Lucretian. But far more satisfac-
tory because descriptive in a luminous way, are the terms
"organismal theory," or if one may be permitted to coin a
word, "organismalism," for the Aristotelian ; and "elemental
theory," or "elementalism" for the Lucretian.

The essence of the idea is set forth with admirable clear-
ness in the early pages of that protogenal book on zoology,
On the Farts of Animals, by Aristotle. "But if man and
animals and their several parts are natural phenomena,
then the natural philosopher must take into consideration
not merely the ultimate substances of which they are made,
but also flesh, bone, blood, and all other homogeneous parts ;
not only these, but also the heterogeneous parts, such as
face, hand, foot, and so on. For to say what are the ulti-
mate substances out of which an animal is foraied ... is
no more sufficient than would be a similar account in the
case of a couch or the like. For we should not be con-
tent with saying that the couch was made of bronze or wood
or whatever it might be, but should try to describe its de-
sign or mode of composition in preference to the material.
. . . For a couch is such and such a form embodied in this
or that matter, or such and such a matter with this or
that form. ... It is plain, then, that the teaching of the
old physiologists is inadequate, and that the true method
is to state what are the definitive characters that distin-
guish the animal as a whole; to explain what it is, both in
substance and in form, and to deal after the same fashion
with its several organs." ^

Not only is the idea itself piquantly stated, but as no one
will fail to notice, the antithetic idea with which it has had
to contend perpetually from that day to this is also unmis-
takably indicated. Another cardinal point will not be
missed: not only does Aristotle sketch these two antithetic

Introductory 3

ideas with a firm hand, but he leaves no room for doubt as
to which side of tlie a^cs-long controversy he is on. He is
always on the side of the organism as against its substance.

Were we permitted to take this statement by Aristotle
out of its setting in his general doctrine of living beings it
would very well present, as far as it goes, the standpoint
that will be maintained in the present treatise. However,
when we come to follow him further and find what his dis-
tinction is between substance and form, and to see how
the latter is related to the soul and becomes involved in the
problems of purpose and necessity, we have to recognize that
in reality the passage comes a long way from meaning what
we should mean by the same words. Wherein the difference
lies will appear as our enterprise develops.

The earliest defender of the opposite idea whom we shall
notice was Lucretius. Although this poet-naturalist pro-
fessed to be a follower of Empedocles and Epicurus, his
formulation of biological elementalism is so explicit and so
readily accessible to modem readers that it will sei've well
the needs of this discussion. In the third, book of The
Nature of Things Lucretius gives his reasons for rejecting
the Greek notion of the "mental sense" of man and animals
as a Harmony — a something which arises as a vital product
of the whole, and then defends at length the counter hypo-
thesis, namely that the mind and soul, that is, life, is a defi-
nite, indep.endent, though complex substance. I quote a
few sentences from the theory which Lucretius is sure is
right, using the translation by the Reverend J. S. Watson :
"I shall now proceed to give you a demonstration, in plain
words, of what substance this mind is, and of what it con-
sists. In the first place, I say that it is extremely subtle,
and is formed of very minute atoms." After illustrating the
activity and pervasiveness of the soul throughout the body,
the author continues : "It must therefore necessarily be
the case, that the whole soul consists of extremely small

4 The Unity of the Organism

seminal-atoms, connected and diffused throughout the veins,
the viscera and the nerves." Then comes a discourse on the
nature of the soul substance: "Nor jet is this nature or
substance to be regarded by us as simple and uncom-
pounded. For a cert~ain subtle aura, mixed with heat, leaves
dying persons ; the heat moreover, carries air with it. . . .
Nor yet are all these constituent parts, aura, heat, and air,
sufficient to produce mental sense or power. A certain
fourth nature or substance must therefore necessarily be
added to these : this is wholly without a name ; it is a sub-
stance, however, than which nothing exists more active or
subtle, nor is anything more essentially composed of small
and smooth elementary particles ; and it is this substance
which first distributes sensible motions through the mem-
bers. . . . This fourth principle lies entirely hid, and re-
mains in secret, within ; nor is anything more deeply seated
within the body ; and it is itself, moreover, the soul of the
whole soul." ^

The further need our enterprise has to draw upon history
as such permits us to leap across nearly eighteen centuries,
for the next occurrences touching these theories which
greatly concern us belong to the period of splendid achieve-
ment in the sciences of living beings from Linnaeus' System
of Nature to Darwin's Origin of Species. The course of
thinking and discovery during this period has been so in-
terpreted as to appear to constitute a virtual proof of the
correctness of the elementalist theor3^ It is said that in the
Linnean era plants and animals were treated from the
standpoint of the organism as a whole, and that later, under
the chieftainship of Cuvier, "instead of the complete or-
ganism, the organs of which it is composed became the chief
subject of analysis." Then, w^ith Bichat leading, came tlie
advance to the tissues ; then before long the discovery w^as
made that not the tissues but the cells are the real units
of structure, Schleiden and Schwann being foremost in this

Itifroductor// 5

forward step; and finally, with tlic demonstration, ac-
complished chiefly by Max Schultze, that one substance,
protoplasm, is the common basis of life in plants and ani-
mals, real biology was attained. This interpretation de-
clares that on the morphological side there was progress
step by step "from the organism as a whole to organs, to
tissues, to cells, and finally to protoplasm, the study of
which in all its phases is the chief pursuit of biologists." ^

This picture is undoubtedly true to a certain extent.
Science surely began with observations on organisms whole
and living, and only gradually did it take them to pieces
to learn their parts and so to deepen understanding. But
in so far as it gives the impression that the study of organic
beings has moved along a direct course from the organism
as a whole toward the ultimate elements or substances of
which organisms are composed, and has become scientific
just in so far as and no further than it has advanced in
this direction, becoming genuine biology only when proto-
plasm is reached, it is not in accord with history or the
nature of scientific knowledge. The introduction of the
word biology into science by Treviranus and Lamarck in the
very first years of the nineteenth century was deliberate
and fully justified though it had no special reference to tis-
sues or cells, much less to protoplasm. But the unfaithful-
ness of the above sketch to actual history which I wish to
point out particularly, concerns the part played by the
group of French biologists of which Cuvier is the best
known member.

It would hardly be possible to miss more completely the
significance of these men than to conceive Cuvier as making
the "organs of which the organism is composed" the chief
subject of study "instead of the completed organism." The
distinctive feature about the school was not the idea of the
organs as such, but as parts of the whole. The ensemble,
the principles of co-existence, or correlation, of subordina-

6 The Unity of the Organism

tion of organs and "characters," are what stand out most
prominently in the writings of these men, so far as general
conceptions are concerned. Cuvier, as above indicated, is
regarded as the central figure of the group, but this comes
more from the vast extent of his achievements and from
his general masterfulness than from his originality and
depth of insight. The leading idea was not due to him, as
he fully recognized, but to the Jussieus, uncle and nephew.
Concerning their Geriera Plantariiim, Cuvier said in his
History of the Natural Sciences: "This work produced a
veritable revolution in botany, for only since its publication
have plants been studied according to the relations which
they exhibit and according to the totality of their organiza-
tion." These botanists, we are told, conceived the organs
and parts to be correlated with one another, i.e., dependent
on each other and united to form the totality of their or-
ganization. Cuvier made this principle his own by adoption,
and applied it with great vigor and success in all his zo-
ological and anatomical studies. His statements of it are
numerous and varied in form, one of the fullest and clearest
being in the "Discourse" with which the Researches on Fos-
sil Fishes is introduced : "Every organized being forms a
whole, a system unique and closed, of which the parts mu-
tually correspond and concur in the same definitive action
through a reciprocal reaction. No part may change with-
out the others changing also ; and consequently each of
them, taken separately, serves as an index and an exposition
of the others." ^

While Cuvier made much of this principle, his shortcom-
ings in understanding and applying it are obvious and far-
reaching. He used it primarily in the interest of classifica-
tion, and classification seems to have been the first goal of
liis scientific endeavor. But it being as little possible for a
Cuvier as for any other thoughtful biologist really to go
no further than to glean and marshall facts, it was exactly

IntrofJuctory 7

this principle that became his speculative stronghold, and
then his speculative undoing. He made it the basis of his
conception of types, and the Type became with him a sort
of Platonic Idea, an eternal, more or less subjective entity.
It was in the hands of Geoffroy Saint-Hilaire, Cuvier's
early collaborator and later antagonist, that the principle
received its best development. Working out a Theory of
Analogies in his Philosophical Anatomy, he considers sev-
eral possible explanations of analogies but rejects all but
three, these being: (1) the relative position, the mutual de-
pendence of organs; (2) the elective affinities among the
organs, defined to mean that "the materials of the organs
survive in some fashion the organs themselves, and, when
the latter cease to exist, the analogy nevertheless does not
cease"; and (3) the balance of organs, the meaning of which
is that "an org^n, normal or pathologic, never acquires an
unusual prosperity, without a related organ, or one in the
same system, suff'ering for it." ^

Saint-Hilaire's application of these principles to the in-
terpretation of rudimentary organs and to teretological
growths show well the thorough- going objectivity of his
conception ; and his Principles of Philosophical Zoology
(1830) are only accentuated examples of the fact that the
organism as a whole, as he looked upon it, was the organism
as composed of all its parts, and further, that he was a
genuine biologist if ever there was one, in spite of the fact
that if he ever saw any protoplasm there is no evidence that
it played any considerable part in his thinking. This whole
group of the late eighteenth and early nineteenth century
biologists must be taken not only as upholders of the or-
ganismal theory, but as having greatly advanced its defini-
tion and application.*

* Were it our purpose in this chapter to present an exhaustive critical
study of the presence and growth of organismal conceptions in biology
it would be necessary to examine somewhere, probably at this point, the
ideas of the oryanicists, a group of embryologists and physiologists who

8 The Unity of the Organism

As we glanced at the organismal and elemental theories
when they opposed each other in the infancy of biology, we
must look at them still opposing each other in this era of
what we may call the adolescence of the science. The or-
ganismal side we have already spoken of in our glance at
the work of the French biologists of the early nineteenth
century. As an elementalist of this period I choose Theodor
Schwann. In his Microscopical Researches into the Accord-
ance in the Structure and the Growth of Aiiimcds and
Plants, published in 1839, he said: "We may, then, form
the two following ideas of the cause of organic phenomena,
such as growth, etc. First, that the cause resides in the
totality of the organism. By the combination of the mole-
cules into a synthetic whole, such as the organism is in every
stage of its development, a power is engendered, which en-
ables such an organism to take up fresh material from
without, and appropriate it either to the formation of new
elementary parts, or to the growth of those already present.
Here therefore the cause of the growth of the elementary
parts resides in the totality of the organism.

"The other mode of explanation is that growth does not
ensue from a power resident in the entire organism, but
that each separate elementary part is possessed of an inde-
pendent power, an independent life, so to speak: in other
words, the molecules in each separate elementary part are
so combined as to set free a power by which it is capable
of attracting new molecules and thus increasing, and the
whole organism subsists only by means of the reciprocal
action of the single elementary parts. So that here the sin-
worked during the first two-thirds of the nineteenth century. Delage
(L'Heredite, p. 750) mentions C. E. Von Baer, Claude Bernard, M.
l?iohtit, W. His and K. Pfliiger as representative of this group. The
philoso])hic'al importance of the ideas held by these investigators has been
emphasized by I.. J. Henderson (The Order of Nature). But there is,
as I believe, a vein of subjeotivistic metaphysics implicit in their con-
ceptions which throws them somewhat out of the main organismal
current.

Introductory 9

gle elementary parts only exert an active influence on nu-
trition, and the totality of the organism may indeed be a
condition, but is not in this view a cause." ^

It is hardly necessary to say that Schwann himself
adopted the view last presented, and that cells were, as he
believed, the "elementary parts" mentioned in his statement.
Under other heads we shall find it necessary to speak with
some fullness of Schwann's doctrinal views and mode of
reasoning. Our needs in this purely historical reference
will be satisfied by calling attention to the fact that he
states the elementalist theory in general terms only, that is,
in terms of "elementary parts" and "molecules." This fact
shows his conception of the problem in the large. His con-
tention that cells are the elements sought must be under-
stood to be an hypothesis secondary only to his broader
conceptions. The recognition of this two-fold aspect of
Schwann's teaching I deem of prime importance, for it shows
clearly that his theory of cells as the ultimate elements of
living beings was not a conclusion arrived at by purely in-
ductive processes, but rather as an interpretation of cells
in accordance with an ancient idea well known to him and
adopted by him. So the very great significance of Schwann's
work must be looked upon in two distinct lights : first, in
that of a generalization of unqualified validity and of the
highest importance, concerning the proximate composition
of plants and animals, that is, their cellular composition ;
and second, in that of furnishing what seemed so solid a
foundation for the ages-old elementalist theory of living
beings as to secure to it well-nigh complete domination of
biological thought for a generation. I think it is not going
too far to say that through the influence of the cell theory
as promulgated by Schwann, following as it did close upon
the foundation of histology by Bichat, the organismal con-
ception lay almost wholly dormant during the fifty years
from 1840 to 1890.

10 TJie Unity of the Organism

This reference to Schwann as an elementalist being
primarily in the interest of our historic background, a crit-
ical examination of his position would be out of place. But
it is desirable to call attention to one important logical, or
perhaps more properly psychological, implication of his
standpoint. The elemental theory applied to organisms
w^hich, as we have just seen, he stated so well and adopted
in his interpretation of the cellular composition of organ-
isms, is in reality not so much of a theory of organic
phenomena themselves as of knowledge of those phenomena.
In other words, Schwann started out in his investigations
not, in the first instance, with a theory of organisms, but
with a theor}^ of knowledge of organisms. The great im-
portance of this mode of approach to biological problems
will be brought out more fully later. Enough is it to re-
mark here that so much has the theory of scientific knowl-
edge applied in Schwann's position grown in definiteness and
influence with time, that to-day many biological elementalists
hold unquestioningly the view that the sum and substance
of scientific knowledge of organic beings is a knowledge of
the elements of which these beings are composed. According
to the theory of biology held by these biologists, the busi-
ness, and the only legitimate business, of the science is to
reduce organisms to as few and as simple elements as pos-
sible ; and in its extreme form the aim is exactly what
it was with the very earliest elementalists, namely to reach
finally one or a very few ultimate elements. To explain or-
ganisms is, according to this theory of knowledge, to reduce
them to their elements, and it is nothing else.

Since 1890 the organismal view has exhibited a rather
vigorous reanimation. Details as to how this has come
about and as to what the renewed manifestations of life
consist in cannot be entered into now. Hovvx'ver, one highl}^
significant circumstance must be noted : the rehabilitation
has h^d little or nothing to do with the form assumed by

hitroduetory 11

the theory in the hands of the French biologists considered
above. It has on the contrary arisen in a sense de novOy and
in consequence of a growing recognition of the inadequacy
of elcnientalism as bodied forth in tlie cell theory applied
to the development of individual organisms. So while we
listen now to voices that have been raised against the at-
tempt to explain ontogenesis as a cellular phenomenon mere-
ly, it must be borne in mind that we are doing so not for
the purpose of examining the cell doctrine in general, but
only to fix attention on the historical fact that the elemen-
talist standpoint as manifested in this aspect of the cell
theory finds itself face to face once again with its old
opponent, the organismal standpoint. The cell theory as
such will demand a chapter for itself, when its turn comes.
The case of the organismal theory is shown with special
clearness in the writings of three American biologists, C. O.
Whitman, E. B. Wilson and F. R. Lillie. Whitman, as is
well known, was primarily an embryologist, his best re-
searches having been on the development of leeches and
bony fishes, and his observations in this field were the start-
ing point for his views on the relation existing between
cells and the organism. In his essay, The Inadequacy of the
Cell-Theory of Development, he says : "Comparative em-
bryology reminds us at every turn that the organism domi-
nates cell-fonnation, using for the same purpose one, several,
or many cells, massing its material and directing its move-
ments and shaping its organs, as if cells did not exist, or as
if they existed only in complete subordination to its will,
if I ma}^ so speak." "^ And he ends the essay The Seat of
Formative and Regenerative Energy, with this : "The fact
that physiological unity is not broken by cell-boundaries is
confirmed in so many ways that it must be accepted as one
of the fundamental truths of biology." ^ The reader should
not fail to notice that while in both these essays Whitman's
arguments were against the hegemony of cells, in the one

1^ The Unity of tJie Organism

case he was looking at the organism primarily from the
morphological standpoint while in the other he viewed it
more from the physiological side.

In the mere matter of extent and deliberateness of re-
liance- upon the principle of organic wholeness, nothing in
recent biological literature with which I am acquainted is
more impressive than what one finds in The Cell in Develop-
ment and Inheritance, by E. B. Wilson. The organism as
a whole or some obvious substitute therefor is appealed to
on no less than seventeen pages of this book, these appeals
being scattered all through from the beginning to the end
of the volume. So far as such views of this distinguished
cytologist have been embodied in a single sentence, the fol-
lowing in his essay. The Mosaic Theory of Dezrelopment
seem to contain them : "The only real unity is that of the
entire organism, and as long as its cells remain in con-
tinuity they are to be regarded, not as morphological indi-
viduals, but as specialized centers of action into which
the living body resolves itself, and by means of which the
physiological division of labor is effected." ^

The most recent and in several ways the most significant
presentation of the organismal theory in relation to cells
comes from another embryologist, F. R. Lillie. It is worth
noting that this time the chief grounds of the presentation
are experimental embryology, whereas with Whitman they
are embryology unaided by experiment. In 1906 Doctor
Lillie published an unusually interesting research on the de-
velopment of a species of worm, Chaefopterus pergamen-
taccus. The kernel of the results was a confirmation and
extension of previous observations by himself and several
other investigators that under certain conditions the embryo
of some species of annelid worms may progress some dis-
tance on the develo})inental course before cellular or even
nuclear multiplication takes place. The author's summary
of facts may be given in his own words : "In general the

Introductory 13

following statement may bo made concerning the differen-
tiation of the uninucleatcd eggs. (1) Organs are never
formed, but only such structural elements as may occur
in single cells of the trocho])hore. (^) Organs may, how-
ever, be simulated by the aggregation of the characteristic
matter of the organ, for instance in the case of the yellow
endoplasm, which simulates the gut of the trochophore, or
the row of large vacuoles situated near the upper margin
of the yellow endoplasm which simulates the row of vacuoles
of the prototroch. (3) Structural elements appear in the
same order of time as in the trochophore. (4) The distri-
bution of the structural elements tends to resemble that of
the trochophore. (5) The yellow endoplasm (yolk?) is used
up, apparently for the maintenance of the metabolism in the
ciliated unsegmented eggs precisely as in the larva." ^^ The
theoretical bearings of the observations are indicated by the
following: "The possibihty of a considerable amount of
embryonal differentiation without either nuclear or cyto-
plasmic division may be considered established. This in it-
self is an important fact, for it disposes effectually of all
theones of development that make the process of cell-division
the primary factor of embryonal differentiation, whether
in the form of Weismann's qualitative nuclear division, or
Hertwig's cellular interaction theory. Further, the phe-
nomenon establishes firmly, as I pointed out in 1901, the
view that the role of cell-division in development is prima-
rily a process of localization.^^

Lillie presents his still broader interpretation in an ex-
ceedingly interesting section headed "Properties of the
Whole (Principle of Unity)." From this I quote somewhat
more at length than is essential for our immediate purpose
of gaining a bird's-eye view of the field we are entering, since
later w^e shall want to examine several of the Items more
closely. "The traditional view, held by many embryologists
at the present day, is that the physiological unity arises in

14 The Unity of the Organism

the course of embryonic development by the secondary
adaptation of originally independent parts to one another;
But this explanation has, in my opinion, become untenable,
and must be replaced by the view that there are certain
properties of the whole, constituting a principle of unity of
organization, that are part of the original inheritance and
thus continue through the cycles of the generations,
and do not arise anew in each. Weismann places this prin-
ciple of unity of organization in the architecture of the
germ-plasm, but, as I cannot accept his view of vast com-
plexity of the germ-plasm, neither can I accept this prin-
ciple in the, sense of Weismann." ^^ . . . "If any radical
conclusion from the immense amount of investigation of the
elementary phenomena of development be justified this is:
That the cells are subordinate to the organism, which pro-
duces them, and makes them large or small, of a slow or
rapid rate of division, causes them to divide, now in this
direction, now in that, and in all respects so disposes them
that the latent being comes to full expression. . . . The
organism is primary, not secondary ; it is an individual, not
by virtue of the cooperation of countless lesser individual-
ities, but an individual that produces these lesser individu-
alities. . . . The persistence of organization is a primary
law of embryonic development." ^^

Without looking further into recent and contemporaneous
literature, enough has been brought forward to show that
the organismal standpoint has a solid footing in current
biological theory. We should, however, be grievously amiss
should we conclude that because the theory has captured
one stronghold it lias won the whole battle. As a matter
of fact, the very men who have admitted the rights of the
organism as against its cells in development are yet far
from admitting those rights as a general proposition; that
is, as against all the elements of whatever order that enter
into its makeup. Thus Whitman says, "If the formative

Introductory 15

processes cannot be referred to cell-division, to what can
tliev be referred? To cellular interaction? . . . The
answer . . . will ... as Wiesncr has so well insisted, find
a common basis for every grade of organization. It will
fin<l the secret of organization, growth, development, not in
cell-division, but in those ultimate elements of living matter
for which idiosomes seems to me an appropriate name." ^*
This sentence, w^ith those immediately following it, leaves
no question that in 1893, when he wrote the essay in which
it occurs. Whitman was at heart an elementalist as much as
was Lucretius or Schwann or Weismann. The only real
step he had taken in the direction of the organismal stand-
point was that of seeing clearly that the cells could not be
'^ultimate units" of organization. Indeed there is consider-
able indication that so far as the general problem is con-
cerned, tlie position he held in 1893 was somewhat backward
from that w^hich he held five years before, when he w^rote The
Seat of Formative and Regenerative Energy, for in that
essay he said: "Let us now consider whether any rational
basis can be found for the idea of a formative power as a
resultant from, and an expression of, physiological unity.
I am fully conscious that the subject is one of profound
mystery, the solution of which appears to lie as far beyond
our grasp to-day as at any time in the past. We draw
nearer to the problem, but the effect is rather to enhance
than to reduce its apparent magnitude. Every step in ad-
vance only brings us to a keener sense of the subtle and
incomprehensible nature of the force or forces contem-
plated." 1^

The extent and nature of Wilson's faltering between the
two standpoints, even as between the organism and its cells,
in spite of his constant and earnest appeal to the the organ-
ism as the "only real unity" we shall consider in some de-
tail when we deal with the cell-theory.

Lillie has, I believe, advanced farther toward the con-

16 The Unity of the Organism

ception that will be defended in this work than either of the
other biologists whose view we are now considering, even
though he Is far from admitting the organism to full stand-
ing in his conceptions. "Undoubtedly," he says, "it [the
principle of unity] is capable of further analysis, and it
must ultimately be derived from particular relations and
properties of material particles" ;^*' and the conceptual form
which the material particles, by virtue of their "particular
relations and properties" assumes in Lillie's mind is the
"formative stuffs" which, since the theory of such sub-
stances was first given definiteness and plausibility by Juhus
Sachs, have figured largely in speculative biology. "The
theory of formative stuffs," Lillie writes, "does away with
any 'determinant' hypothesis. 'Characters' are not due to
'unfolding' of the 'potencies' of 'detemiinants' but are re-
sults of morphogenic reactions between two or more forma-
tive stuffs. The 'character' need no more be preformed in
the reagents (formative stuffs) in the case of a morphogenic
than in the case of a chemical reaction." ^^

This interesting, and up to a certain point entirely ac-
ceptable, language of Lillie's will be examined more closely
in another connection. Enough for now to say dogmatically
that the author's "formative stuffs" is only another elemen-
talist refuge and so no more satisfactory than is the cellular
refuge which he himself abandons, or than are any of the
innumerable other refuges to which innumerable other ele-
mentalists have fled.

The historic background for our enterprise will be com-
pleted when we have pointed out how it is faring with these
two theories at present. This can be done with great brev-
ity since what we find will be exactly what will most occupy
us when we come to the substantive rather than the historic
part of our task, when the superstructure rather than the
foundation is at hand.

The organismal line of descent which our cursory sur-

Introductory 1*7

vcy has traced from tlic period of Aristotelian zoology,
through that of French comparative anatomy of the late
eighteenth and early nineteenth centuries, through what
might with propriety be called the period of American em-
bryology, now barely ended, holds its unmistakable course
on into what we may speak of as a physiological period,
in the midst of which we now are. It should be remarked
tliat "physiological" as lierc used does not refer so much
to pliysiology in the professional sense as to an approach
to certain developmental phenomena of the organism from
the functional side, since the biologists who are tending to-
ward the organism al theory are not primarily physiologists
but students of individual development.

The term most characteristic of this latest outcrop of
organ ismalism is correlation, and what is distinctive about
the present effort as contrasted with that which marked
the idea of correlation held by the French anatomists is
tliat now the correlatedness of parts in the organism is being
h)oked at from the functional more than from the structural
side ; and that the necessity is felt more than it was in the
earlier period, of finding a causal explanation of the correla-
tions. "Equilibrium" is anotlier term that is frequently
used by the biologists whose thinking is of this cast, and
the kinship of this to Saint-Hilaire's "balance" will not
escape the reader's notice. This doctrine of physiological
correlation is receiving its fullest elaboration at the hands
of C. M. Child, though numerous investigators are con-
tributing importantly to it. K. Goebel, E. Radl, W. Pfeffer,
L. Jost, J. Nusbaum, E. Schultz, H. Rand, S. J. Holmes
and C. Zeleny may be mentioned as biologists who have
dealt more or less directly with the problem. Undoubtedly
H. Driesch's "harmonious equipotential systems" ought to
be mentioned in this connection, though this author's un-
qualified commitment to an extra-natural explanation of
biological phenomena will hardly permit us to enroll him

18 The Uiiity of the Organism

in the group of workers referred to.

The organismal standpoint escapes its ancient adversa-
ries when it comes to expression as physiological correlation
just as little as it has escaped when it has appeared under
any of its earlier forms. Thus although correlation plays
a large role in the writings of W. Rbux, the founder of
developmental mechanics, approach to the correlation-com-
plex for him seems always to be from the direction of the
elements in the complex and never from that of the complex
itself ; so it results that the organism as such has no stand-
ing in his conceptions on a par with that of the elements
which constitute it. This fact comes out clearly from an
examination of the various definitions bearing on the point
given by Roux in his Terminologie der Enhdcklungsme-
chanik der Tiere und Pfianzen. Thus as a definition of or-
ganism we find '^Orgajiism means a complex of organs ; hence,
of instruments." ^^ Or for living being (regarded as a syn-
onym for organism) we find: ^^Limiig beings^ bion, pi. bion-
ten, are natural bodies which distinguish themselves
'minimally' from inorganic natural bodies through a sum
of definite elementary functions which directly or indirectly
subserve self-preservation, as also through self-regulation
in the exercise of all these functions ; and thereby, in spite
of 'self-alteration,' and through the same, and also in spite
of the necessary complicated and soft structure, are very
permanent." ^^ Again, " 'Ganzbildung,' Holoplast, is a more
or less fully developed, but fully formed structure, represent-
ing an entire organism, which has arisen out of a blastomere,
or egg-fragment." ^^

From these as typical definitions it is seen that in no case
is organism conceived and defined as having characters
wholly its own, but, by implication, only those belonging to
its parts. Indeed, a critical study of the speculative writ-
ings of Roux and his adherents will, I believe, convince any
one that tlie most characteristic thing about developmental

Introductory 19

mechanics as a system of thinking on biological subjects is
its effort to deal with organisms in terais of parts of or-
ganisms; otherwise expressed, that it is a systematic effort
to avoid recognizing the organism in itself as a true objec-
tive entity. Because of the persistence, industry, enthusiasm,
and withal great ability shown by Roux in applying ele-
mentalism to many aspects of living beings, his title to
chieftainship of what the Germans call "Zersplitterungs-
theorien" can hardly be disputed, at least so far as this
present era is concerned.

We shall have to deal with both the practical and theoret-
ical sides of the Rouxian school under several other captions,
but this much may be said now. Developmental mechanics
has one great merit over any other form that elementalism
has taken at any time in the history of biology, in that it
gives ungrudging recognition to many orders of constituent
parts of plants and animals. Organs and tissues of various
grades and classes — cells, nuclei, chromosomes — in short all
the parts of the organism, are accepted as real existences,
only the organism itself being ruled out. In this respect
Roux's elementalism is far more genuinely biological and
scientific than is, for example, the purely chemical form of
elementalism, that form which virtually denies reality not
only to the organism as a whole but to all of its parts except
what in its most general mode of expression it calls the
"living substance."

Superior in some respects as the conceptions underlying
developmental mechanics are to those underlying purely
chemical elementalism, far more superior are they to that
form of elementalism the citadel of whose biological faith
is constructed from deepest foundation to highest pinnacle
of "hypothetical living units," of which Spencer's physio-
logical units, Darwin's pangens, and Weismann's determi-
nants are the most famous examples. The reason why
strictly metajjhysical conceptions of this type all prove to

20 The Unity of the Organism

be so noxious to scientific biology we shall point out later.

Finally, to bring our historical survey to the present
hour, brief reference must be made to the form the contro-
versy has assumed in its very latest stage. To show that
the Mendelian-unit-character-factorial-chromosomal theory
of heredity has become thoroughly permeated by the elemen-
talistic philosophy will be one of the cardinal aims of some
of our critical chapters. This philosophy more than the in-
trinsic importance of the objective discoveries is what has
aroused the imagination and enthusiasm and stimulated the
activity of geneticists, as the new school of investigators of
sexual reproduction call themselves. Reference to this lat-
est phase of biological elementalism cannot serve the future
in any better way, I think, than by calling attention to the
remarkable illustration furnished by these late developments
of the narrowing power of elementalistic philosophy.

A calm and just judgment of what the strongest motive
in philosophical biology is to-day, would be that it is a firm
belief that the most imjDortant problems of the whole living
world are centered in — what? Sex-cells.'^ No, not even in
entities thus large and complex ; but in a few minute and
relatively simple fractions or parts of these cells, the chro-
mosomes !

Viewed broadly both as to historical development and
factual content, we are warranted in being confident of the
triumph of the organismal standpoint at a day not far dis-
tant, this confidence being warranted largely by the fact
that it seems as though elementalism has run nearly its
whole natural course. It has consumed all the material there
is for it to live on, as one may say. It is now engaged in
trying out the very last portion of the organism as the
"seat" or ultimate explanation of life phenomena. This
judgment of the situation becomes especially cogent if the
broadly generic term "chemical substances", be put in the
place of "hereditary substance" or "genes" which are imag-

Introductory 21

ined to make up largely or wholly the chromosomes.

A striking example of the rapid progress made by ele-
mentalism toward its own extinction through contracting
itself to nothingness is furnished by the course of speculation
about ultimate biological units from the period of Spencer
and Darwin to the present moment. Spencer's physiological
units were by no means restricted to the germ-cells but
were held to permeate the whole organism. In this the
doctrine had a strong organismal flavor. And Darwin's
gemmules had an unmistakable organismal leaning in that
they belonged to the organism as a whole at least as much
as to the germ-cells. His conception was one of pan or uni-
versal genesis and not merely of genesis from germ-cells
toward soma. In fact, the main object of his quest was an
explanation of how body, or soma, may influence germ-cells.

After Darwin came the next long step toward elementalist
reductio ad ahsurdum in Weismann's proposal to limit the
efficient ultimates of organization, the determinants, to the
germ-plasm whether this be in sex or other reproductive
cells ; that is, to so conceive the ultimate nature of the or-
ganism that there should be no reciprocal action between
soma and germinal elements ; that the whole movement, both
individual and racial, in organic evolution should be a one-
way movement, that way being from invisible germ to visible
organism.

Finall}^, there has arrived the ultra-modern school, the
geneticists, with those wonderfully efficient instruments of
analysis, the factorial hypothesis of Mendelian inheritance,
and the hypothesis that chromosomes are the "seat" of the
"factors" of heredity. These two hypotheses coupled to-
gether and with the hypotheses that all evolution is by mu-
tation, and that all mutations consist in the dropping out
or losing of factors and characters, need only to be pushed
hard enough and speculative biology will be carried to its
apotheosis and objective biology to its extinguishment.

S2 The Unity of the Organism

How far theorizing has gone on this road is indicated by
the much noticed address by WilHam Bateson, one of the
foremost MendeHan geneticists, as president of the British
Association for the Advancement of Science in 191^. In this
address Bateson suggested, whether with full seriousness or
not no one seems quite sure, the above mentioned hypotheses
of the loss-of-characters method of origin of all organic
species.

The chromosome theory having been elaborated into what
it now is, the easy step, to the conception that the First,
or Original Organism, as something close of kin to a chro-
mosome, has already been taken by an able student, E. A.
Minchin, the imaginary Primal Organism being called by
him "Biococcus." This speculation we shall consider in our
f oraial discussion of the chromosome theory of heredity.

To bring together these suggestions by Bateson and Min-
chin and elaborate them into a complete, well-rounded theory
requires only a biologist, preferably a German, with the
industry and learning and imaginative logic of a Weismann.
This accomplished, the ultimate nature and the evolution
of the whole past, present, and future organic world would
be causally explained by referring it to a primordial chro-
matinic hierarchy which contained the detenniners, or fac-
tors, of all later visible organisms, and from which these
issued by the transformation of latent into actual organisms
throuo;h the removal of factors which inhibit the actuation
of other factors. But practicable as such a complete ex-
planatory theory is, and harmonious as it could readily be
made with certain far-reaching and widely favored concep-
tions in modern physics, it is very doubtful if the enterprise
is ever carried out — at least for any other purpose than as
an illustration of how elaborate and consistent and withal
beautiful a structure can be erected by pure logic.

My main reason for believing the entei-prise will never be
carried through, seriously, is that the organismal stand-

Introductory 23

point has already advanced so far on secure observational
and experimental and inductive foundations, that the scien-
tific uselessness if not folly of such elementalistic systems
will deter working biologists from spending their time on
them.

The barest mention of some of the most important lines
of organismal advance, just referred to, will fittingly close
tliis historical sketch.

From the standpoint of biology in the narrowest sense,
no researches are yielding more of organismal significance
than are those on internal secretions or hormones, or "chem-
ical messengers" as they have been called by Starling, one
of the foremost investigators of these substances. Two
chapters of the constructive part of this work are devoted
to this subject.

Another province in which research is yielding results
scarcely if at all secondary in significance to those coming
from the biochemical realm just mentioned, is that on the
integrating office of the nervous system. The fundamental
and extensive work of Sherrington is of prime importance
here. But a genuinely organismal aspect is recognized in
the tropism theor}^ of Jacques Loeb, which turns out to be
almost as important for our general enterprise as the unify-
ing character of the nervous system.

Finally, the realm of the indubitably psychic life of or-
ganisms, particularly of man, is found to contain much of
the utmost usefulness to the organismal conception. Espe-
cially to be mentioned in this connection is the doctrine
of Apperception as understood and worked out by Wundt,
and its relation to the tropism theory, this relation having
apparently been first pointed out by Royce. A discussion
prominently involving this relation w^ill conclude the con-
structive part of the volume.

24 The Unity of the Organism

Nature and Scope of the Undertaking

The foundation of our enterprise, so far as historic sum-
mary is concerned, being laid, we may now exhibit the plans,
floor-plans and elevations, as architects say, of the super-
structure; but the barest outlines will suffice. Leaving off
figurative speaking, we must now state in bald outline the
central aim of the undertaking. It is to show that while
the two conceptions, the organismal and the elemental, con-
tain much that is thoroughly irreconcilable, there is a great
substratum of truth underlying both. Adhering to the mode
of expression previously used in characterizing the two
points of view, the central idea which we shall try to es-
tablish may be put as follows : The organism in its totality
is as essential to an explanation of its elements as its ele-
ments are to an explanation of the organism. This formula-
tion which has been in service with me for many years in
university lectures and in verbal discussions with colleagues,
is approached, somewhat remotely by several authors, earlier
and later. Thus L. Rhumbler says at the conclusion of the
article Correlation, in tlie Handworterhuch der Naturwis-
senschaften: "One may assume perhaps that each function
of an organ, etc., is bound correlatively to the functions of
all other organs, even though perhaps many times in the
slightest way and through means in part replaceable, so that
by this the organism as a whole is influenced to a definite
degree by each of its organs, and vice versa [that] through
these numberless influences the so-called influence of the
whole upon the parts in turn finds its explanation even
though complicatedly and at present reaching only to some
details." ^^ We have here the Rouxian form of elementalism
at which we have already glanced, but it seemed worth while
to notice this particular expression of it since its advance
toward organlsmalism as contrasted with chemical elemen-
talism is well brought out.

Introductory 25

We may preface a slight expansion of our dogmatic
formula by asking the question, "How is it that the prin-
ciple, embodied in such phrases as the 'Organism as a whole'
so confidently used by eminent investigators, sliould be so
distrusted by most biologists as to give it little influence on
biological conceptions?" The proximate reply is that for
most biologists the notion is too vague and general to be
of high and permanent worth. One statement of this de-
preciatory estimate is that to take the organism in its en-
tirety is to take it unanalyzed ; and this, so such a view
holds, is superficial and contrary to the whole purpose and
spirit of modern research. To analyze complexes of natural
phenomena, that is to reduce them to their elements is, ac-
cording to this view, exactly what makes science science.
Scientific knowledge in biology as in all other fields, is ana-
lytic knowledge; and conversely, analytic knowledge not
only is science, but (at least so says full-fledged elemental-
ism) is the whole of science. Our undertaking will require
us to combat, incidentally but yet vigorously, this view.
Stated positively, while assiuning as science always does as-
sume, the validity of analytic knowledge of nature, we shall
contend that synthetic knowledge of nature is not only valid
also, but that it is as foundational and essential a part
of science as is analytic knowledge. Furthermore we sliall
touch briefly, but as we believe very fundamentally, the
question of the nature of synthetic knowledge itself.

In accordance with this general statement of purpose,
I hope to be able to clear the conception of the "organism"
taken alive and whole, of the vagueness that has hitherto
enveloped it and make it as clear, as sei-^^iceable, and as in-
dispensable to science as are "foot"' or "liead" or "brain,"
or "eye" or "muscle" or "cell" or "ovum" or "nucleus"
or "chromosome" or "nucleo-proteid" or "ptyalin" or any
other fully accredited and unescapable biological entity.
Let me state the case from a slightly different angle, attach-

^6 The Unity of the Organism

ing it to a quotation from E. B. Wilson given in our historic
survey. This quotation is : "The only real unity is that of
the entire organism." This I would modify thus : The entire
organism is not the only real unity but it is a real unity, and
represented by the highest animals, especially man, is the
supreme unity.

Whatever warrantableness there may be in the prejudg-
ment among biologists to the effect that the "organism as
a whole" connotates "the organism unanalyzed" even if not
unanalyzable, will I hope be met largely by the phrase "Or-
ganismal Integrity" of which I make much. Obviously, if
one stops to reflect a little, "the organism as a whole" if
taken strictly, could mean nothing less than the organism
and all of its parts. The whole would not be the w^hole if
some of its parts were omitted ; so even from this standpoint
one might contend that "the organism as a whole" must
mean the organism taken wholly, that is, through and
through, no part being neglected, and that consequently
instead of connotating the organism unanalyzed, in reality
it connotates just the opposite and thus indicates the only
starting point for complete analysis of the organism. But
"organismal integrity" not only carries all the other phrase
implies so far as mere totality is concerned, but it does more
in that integrity and its etymological kindred, point defin-
itely not only to the parts, but to them as interdependent.
The past participial form of the verb integrate, i.e., in-
tegrated, we shall find particularly serviceable, it being sus-
ceptible of use in the comparative degree. The greater or
less extent of integratedness of organisms we shall need to
speak much about as we proceed. Again such tenns as
integration, integrally, and integrality will, upon occasion,
contribute to precision and flexibility of expression. The
kinship, both as to terminology and conception, between
what is foreshadowed in the justification of the phrase or-
ganismal integrity and Herbert Spencer's Physiological In-

Introductory 27

tegration will not escape the notice of any reader acquainted
with Spencer's ideas, particularly if he be at the same time
acquainted with the conception as adopted by O. Hertwig
and made the third law in his Theory of Biogenesis. Hert-
wig's elaboration of this law contains more probably that
accords with my central thesis than does any other writing
known to me.

A brief on the procedure which will be followed in devel-
oping our thesis may now be given.

Part I will be devoted to setting fortli efforts that have
been made in recent and present-day biology to deal with
several great classes of the constituent ])arts or elements
of organisms in accordance with the eknientalist theory.
If my basal proposition be true that tiie organism taken
alive and whole is as essential to an explanation of its ele-
ments as its elements are to an explanation of the organism,
then it would follow that all attempts to assign explanatory
values to the elements in their relation to the whole organ-
ism, while at the same time denying either expressly or
tacitly, similar values to the entire organism in its rela-
tions to the elements, must fail in large degree.

And here comes in sight a vitally important aspect of my
general standpoint. Were the basal proposition just stated
handed out as a postulate, that is, as a proposition the ac-
ceptance of which is demanded without proof, or were it
even held to need no other proof than such as might be ad-
duced by syllogistic reasoning alone, in the manner, for ex-
ample, that both Aristotle and Lucretius mainly supported
their views, our task would be comparatively simple. As an
illustration of how easily organismalism could be demon-
strated by this method, take the case of the relation of the
organism to its cells. We should first point out in general
terms what characters certain groups and classes of cells
might be expected to show in accordance with the hypothesis
that the larger structural and functional requirements of

28 The Unity of the Orgamsm

the organism influence its elements, and then search among
the cells for examples of such influence. But this, the de-
ductive mode of reasoning, is a complete antithesis to that
on which we shall chiefly rely in this treatise, indeed to that
on which biology always has chiefly relied so far as its prog-
ress has been healthy and vigorous and straight ahead.

Holding, consequently that the proposition must be in-
ductively established if it is to be established at all, the
heavy task devolves upon us of examining, as above in-
dicated, a great range of the biological field to see how it
fares with the two opposing hypotheses (and viewing the
theories from the present stage of our enterprise, they
should be considered as hypotheses in the strictest sense)
when they are tested by a great number of fully authen-
ticated observations. From this general statement it is
apparent that the first division must be for the most part
distinctively critical. That, however, it is not wholly of
this character, I trust will be patent enough to the attentive
reader.

Part II will consist of a systematic presentation of the
fullv established inductive evidence which, if fairlv consid-
ered, compels, as I believe, the adoption of some such
general view as that here defended and would be called,
according to nomenclatorial precedent, organismalism.

On behalf of this unauthorized and rather bungling word,
I make no plea. In fact, the use of it goes against the grain
with me somewhat and I avoid it as far as possible. The
sum and substance of the situation is, though, that the term
seems to force itself upon me at times. It corners us, so
to speak, and will not let us escape without taking it u]) and
carrying it with us. But perhaps the possession of such
power as this is just wliat entitles new words to live. If so,
and should tlic idea prevail for which the word stands, the
word will prevail too unless some one liaving special com-
petency in fabricating words finds a better. Which of these

Introductory

29

alternatives may befall is imniaterial. My only concern is
for the idea. If that survives and flourishes I shall be satis-
fied, no matter under what name it becomes known.

1. Aristotle ('11)

2. Lucretius

3. I>ocy 139

4. Merz II, 240

5. Saint-Hilaire 314

(). Schwann & Schleiden 191

7. Whitman ('93) 119

S. Whitman ('88) 49

9. Wilson ('93) 9

10. Lillie, F. R 237

11. Lillie, F. R 245

12. Lillie, F. R 251

13. Lillie, F. R 202

14. Whitman ('93) 123

15. Whitman ('88) 43

16. Lillie, F. R 253

17. Lillie, F. R 258

18. Roux ('12) 287

19. Roux ('12) 241

20. Roux ('12) 163

21. Handworterbuch II, 736

Chapter II
THE ORGANISM AND ITS MAJOR PARTS

Reflections on the Problem of Individuality in the living

World

THERE has been a great deal of inconclusive discussion
of late years, about the nature of the organic indi-
vidual. Biologists holding the natural-history viewpoint
have never had much difficulty in making up their minds as
to what an individual is, but many experimenters, encounter-
ing problems presented by the parts of an individual and by
individuals as parts of a society, have tended to dodge the
issue — have attemjjtcd to find a solution to the puzzle of
individualit}^ by the rather naive method of changing their
definitions of it.

To get some clear-cut idea on this question, out of the
welter of nebulous notions that prevail at present, is so im-
portant for our general discussion that we can afford to
stop for a moment to consider it.

A homely and common illustration will serve as a starting-
point. When a scientific dairyman is buying a milch cow
or a bull, the deciding factor in the deal is usually what he
calls the animal's "individual performance." That is, while
various separate "])oints" are taken into consideration and
pedigree lists are consulted, the final decision is based not
so much on these as on the cow's record as a milk producer
or the bull's as a sire of good calves. In the estimation of
the purchaser, the animal stands or falls on its own merits
as an individual.

30

The Organism and its Major Parts 31

While the individual plant docs not appear quite so con-
spicuously in plant husbandry as docs the individual in ani-
mal husbandry, it is still never a negligible, and is often an
important element. This is especially true in horticulture,
where individual performance is subject to much the kind of
testing that is applied to the individual animal, namely that
of seasonal repetition. In a well kept orchard, for example,
the individual tree holds a prominent place.

To question the reality of the individual cow or apple
tree would be, to a breeder or orchardist, equivalent to
questioning the reality of any such animal at all as a cow,
or any such plant as an apple tree. Yet a considerable
number of zoologists and botanists have been thrown into a
distracted state of mind as to the reality of the individual,
especially among the lower orders of plants and animals.
Botanists have been particularly subject to this malady,
obviously because in none of the plants, not even the highest,
are the individuals so thoroughly integrated as they are in
most animals, particularly in the higher classes. And so,
as we shall see presently, some speculative botanists have
gone to the ridiculous extreme of asserting that there is no
such thing as an individual plant.

What, exactly, is the matter with biological reasoning
which lands men in such absurdities? For absurdities they
surely are, even though given the habiliments of science.
Test the matter this way : If I look at a tree and a man
standing beside each other, there is, so far as this observa-
tion is concerned, not a shred of valid objection against
applying the term "individual" to each. The one is an
individual tree and the other an individual man, and the
individuality of neither is a whit less certain or more cer-
tain than that of the other, as I now perceive the two.

But as I now perceive the two is exactly what we are
here discussing. For anybody to contend that one of these
beings — the man' — is an individual, while the other — the tree

32 The Unity of the Organism

— is not, merely on the ground of what is learned by later
study about the differences in makeup of the two, is literal
nonsense. It is a virtual denial of the validity of oberva-
tional knowledge. Granted that science can not rest satis-
fied with "common-sense" knowledge, there is still no ground
for repudiating all commonsense.

Attempting to ascertain what the trouble is with biolo-
gists who reason thus about individuality, one soon dis-
covers that the botanist who deals with a tree thus unjustly
quite ignores the obvious and unescapable fact that the raw
material of all his botanical knowledge is individual plants
taken one after another; that for trees there is an each tree;
that each, as it actually stands before him, is one, not two
or three or any other number ; and that it is not in the least
confusable witli any other tree, no matter if several are
connected together by their roots or in some other way.
These confused-minded persons either ignore the patent facts
of observation., or if their sophistication is refined, they deny
the validity of the "mere perception" of an individual when
that way of predicating individuality is measured against
supposedly more fundamental principles of scientific knowl-
edge-getting, as analysis is held to be.

This question of more and less fundamental principles
of scientific procedure, especially those involved in analysis,
is undoubtedly of great importance. But undoubtedly, too,
it is a question of the nature of scientific knowledge rather
than of the nature of plants and animals, so does not fall
within the scope of such a treatise as the one now occupying
us. The question before us is that of the nature of the in-
dividual organism.

As soon as we see the necessity of separating these two
questions, and address ourselves to the strictly objective
question, we perceive that the difficulties center around the
fact that no individual plant or animal is simple in its con-
stitution, but in alniost all cases is exceedingly complex,

The Organism and its Major Farts 33

The kernel of the difficulty arising from the complex make-
up lies in the fact, emphasized by recent investigations, espe-
cially those on regeneration, that in very many animals and
plants, when the individual is artificially divided, parts of
individuals have remarkable powers of independent life, even
to the extent of reconstituting themselves into other indi-
viduals as perfect as the one that was divided. The reason-
ing from these facts is, essentially, that because a given in-
dividual may divide or be divided artificially into two or
more parts, which may in turn develop into other individuals
like the original, the original was therefore not a single in-
dividual. In other words, individuality is denied these or-
ganisms because of what parts of them can do when severed
from the whole. The unity, the integrity of the individual
is called in question, not on account of what it is here and
now, but on account of what the parts may do after they
have heen severed, naturally or artificially, from the original
unity.

No biologist, and especially no organismal biologist, would
minimize the significance of the fact that the severed parts
of many organisms possess such remarkable reconstitutive
powers. The organismal biologist, I assert, is especially
interested in the phenomena because they are to him unique
and unanticipated evidence favorable to his general stand-
point. What he denies is that the phenomena count a scin-
tilla against the reality and essentiality of the individual.
He points out that their importance, so far as the prob-
lem of individuality is concerned, is not that they show much
about the ultimate nature of the individual's unity, but that
they do show much about the degree of that unity.

The Individual Plant and Its Parts

The purposes of this chapter will be best served by de-
voting a section to examining a few efforts which have been

34 The Unity of the Organisin

made to interpret the organism in accordance with the
theory which denies its individuahty. Our first instance will
be taken from botany. But before proceeding with this, it
is desirable to point out that some of the most distinguished
botanists, especially physiological botanists, have recog-
nized the unity of the plant without stint or cavil.

We appeal to only one of the botanists of this class,
PfefFer. In The Physiology of Plants, he says : "The in-
timate correlation of the entire vital mechanism renders it
probable that every excitation exercises some effect upon
other manifestations of irritability, even though this effect
may not always be directly perceptible."^

Again : "In the plant community the activity of every
cell and of every organ is subservient to the common weal,
and may, when necessary, be modified as already indicated
so as to fulfill the changed requirements of the whole. "^

It is true, I believe, that the mode of thought about plants
illustrated b}^ these quotations is characteristic of botanists
in whom observation and speculation maintain a due bal-
ance; botanists with whom, in other words, speculation has
not got the upper hand of obsei'vation.

It is highly significant that one of the most pronounced
and, so far as I have discovered, earliest authors to specu-
late on the non-individuality of the plant was Schleiden, one
of the fathers of the cell-theory. In his famous Contribu-
tion to Phytogenesis we read in a discussion of the individu-
ality of plants : "In the strictest sense of the word, only the
separate cell deserves to be called an individual."^ Elabor-
ating this notion, "The woody stem," he tells us, "cannot
come under the idea of a plant." And further: "It neces-
sarily pertains to the notion of a plant, that it produces
foliaceous organs on its stem, yet there is no tree which
produces leaves."^ This last statement sounds, the author
admits, rather paradoxical, but, he contended rightly
enough, the mere circumstance of its sounding paradoxical

The Organism and its Major Parts 35

\

docs not prove it false. Since, as we have previously seen,
Schkiden's brand of elcnientalisni necessitated the sacrifice
of the individuality of the 2)lant to that of tlie cell, our
critical examination of it belongs properly to our examina-
tion of the cell-theory. Here, consequently, we do no more
than point out that Schleiden himself did not succeed in
carrying through fully his simple denial of the plant's unity.
The oneness of the young dei'dopincj j)lant was an obstacle
to his theory, even though he seems not to have been aware
of the fact. "After the wood}' mass is formed, we miss,"
he says, "the influence of the law of formation, which until
then had without exception directed the growth of the entire
jilant in all its parts. "^

Schleiden seems to have felt no difficulty in his conception
that the "law of formation" w^hich "directed the growth of
the entire plant in all its parts" could be accounted for by
the "separate cell," the only individual "in a strict sense."
His immunity from qualms on this score was due probably
to the fact that, being an "ultimate problem" botanist in-
stead of a naturalist really interested in plants, it did not
occur to him that the question of how^ the cells could explain
the fact that in one instance the "entire plant in all its
parts" shbuld be an apple tree, in another an oak tree, in
a third an orange tree, and so on, might be considered a
really important one by somebody.

We now pass to the examination of a single modern in-
stance of the attempt to "explain away" the individuality
of the plant. The principle made use of in this attempt is
that of symbiosis, which is a sort of partnership between
organisms of different species, so close in some cases as to be
really organic. Although I do not know that the example
I have chosen has had much recognition among botanists, it
yet seems justifiable to use it since it is certainly typical,
even though possibly somewhat extreme. It is taken from H.
C. Davidson, an English botanist, his publication being en-

36 The Unity of the Organism

titled The Nature of the Plant. After illustrating the prin-
ciple of symbiosis by referring particularly to the case of
the mutually dependent combination existing between the
flat-worm Convoluta roscoffensis and a green alga, recently
well studied by Keeble and Gamble, Mr. Davidson goes on
to argue that if a typical plant, a tree for example, be
considered to be a like sjanbiotic complex, "much that
has been dark in the vegetable world becomes clear."^

The members of the partnership in the plant so con-
ceived would be the flowers, equivalent to the "hermaphro-
dites and males and females" occurring in the world of in-
sects, and the buds equivalent to the underdeveloped females
or neuters. Among the darknesses enveloping plant life
which the author believes would be illumined by this theory
he mentions that of the plant's individuality. In the light
of the theory it becomes obvious, the author holds, that a
"plant is not, as is generall}^ supposed, an individual entity,
but in reality a group or family of individuals, associated
within a common protecting envelope, the bark, and upon a
common root for the common good."^ These "associated
individuals" Mr. Davidson calls ylantagens since, he says,
"they cannot well be written about unless they have a name."

Another meritorious thing about the plantagen theory,
its inventor believes, is that it removes the difficulties in the
way of the germ-plasm theory of Weismann, presented by
plants. The type of reasoning which has given rise to this
rather ingenious speculation will receive due attention in
various parts of this volume. I bring up the case here only
as a specific instance of "certain general tendencies to er-
roneous reasoning" above referred to. There is always the
inclination to ascribe more casually interpretative value to
some of the parts of organisms in their relation to other
parts and to the whole than actually belongs to them. In
the present instance this eff^ort is seen in the fact that both
the asexually and sexually propagating elements of any

The Organism and its Major Parts 37

given plant are treated as though they were distinct, ulti-
mate data, whereas they certainly are not. The term
"symbiosis" was introduced into biology exactly for the
purpose of expressing the fact that individual organisms,
usually of very distinct species, get together in an intimate
relation wherein one or both members of the partnership
gain some advantage, each at the same time preserving its
unmistakable identity. There is certainly not the slightest
evidence that tlie asexual and sexual parts of plants were
originally independent of each other in this way.

Let us accept momentarily (since his speculation is de-
pendent on our doing so) Mr. Davidson's contention that
"germ-cell must develop from germ-cell, bud from bud, in-
dividual from individual." Even so, no biologist who is a
genuine believer in organic evolution, that is, in the teach-
ing that all organic kinds have descended from ancestors of
different kinds, can allow that "much tliat has been dark
in the vegetable world" is made any less dark by the as-
sumption of such a fundamental independence of germ-cells
and germ-buds and "individuals" until he is informed as to
the ancestry, not only proximate but remote, of germ-cells
and germ-buds and "individuals."

The kinship between these modern speculations about sym-
biosis and an ancient notion due, it seems, to Empedocles,
comes to light at this stage of the discussion. What that
notion is we shall see presently. Mr. Davidson's symbiosis
theory of plants involves, he points out, his theory of plant-
SigenSy which last theory involves, as he rightly says, the
conception that "germ-cell must develop from germ-cell,
bud from bud, individual from individual." But any ten-
year-old farmer's son may know this statement is not true.
Keeping the fonn though not the meaning of Davidson's
expression, such a boy can assert that germ-cells develop
not only from germ-cells but also from buds, and that buds
develop not only from buds but also from germ-cells.

B8 The Vnity of the Oi'ganism

Following a killing frost in southern California a few
years ago, thousands of lemon trees whose normal foliage
had been destroyed put forth great numbers of new shoots
on their trunks and largest branches. Such new shoots may
occur anywhere and everywhere on the trunk and branches,
and since they rarely arise, so long as there is no occasion
for them because of the activities of the normal foliage, the
term "adventitious"* is appropriately applied to them. So
lemon-tree germ-cells and lemon-tree plantagens, or speak-
ing in terms free from speculative sophistry, lemon-tree
seeds and lemon-tree buds, are dependent for their origin
upon lemon trees. In other words, the tree is as essential to
a causal explanation of the seed and the bud as the seed
and the bud are to a causal explanation of the tree.

Reproduction by adventitious buds among the higher
plants is so important from the organismal standpoint that
we must consider it a little further. One additional fact
which the reader should appreciate is that the method is by
no means an exceptional and insignificant thing in plant
economy. It is a regular way many trees have of perpetu-
ating themselves. An illustration of this even more striking
than that of the lemon tree is furnished by the Coast Red-
wood of California {Sequoia sempermrens). A stump of
this tree, even a stump that has passed through a severe

* The question of adventitious or cambium buds from lemon trees
seems not to have received much attention from botanists. Judging from
the distribution of the new growths in such an epidemic, as it miglit
be called, of budding as that which takes place imder conditions like
those here mentioned, there is scarcelv a doubt that verv many of the
new l)ranches arise quite independently of previous bud germs; in other
words, from some source not germinal mitil it becomes so under the
special conditions. The only experimentation on bud production in the
lemon with which T am acquainted has been carried on by Prof. H. S.
Reed of the Citrus Kxperimeut Station of the University of California,
at Riverside. Doctor Reed has kindly shown me the results of his
work and pennitted me to make use of them in this coimection. So
far as these experiments go, it seems that while leafless pieces of
branches kept under suital)le contlitions readily put out undoubted cam-
bium buds, these produce roots only.

The Orgatiism and its Major Parts 39

forest fire, will put out thousands of shoots. That these
arise from the cambium I am assured by Dr. Percy Brandt,
a botanist who iias given special attention to the matter.
Now I ask the reader to reflect on what is before us here.
When the tree's life not merely as an individual but as a
potential parent is destroyed, so far as all visible evidences
are concerned, one of the general tissues of the stump, its
cambium layer, proceeds forthwith to do what under the
normal life-conditions of the tree it does not do, namely,
produce new buds, each one a potential new redwood tree.
The indubitable facts compel us to recognize that any part
whatever of the cambium, at the base of the tree at least, is
capable of being diverted from its normal function and
made to do what it would not do except for the special con-
ditions imposed. I say it is "made to do" these things rather
than merely that it "does" them as though from its own
inherent nature alone, simply because it does not do them
unless they are subjected to the very particular conditions
which are imposed, namely those of the destruction of the
normal propagative parts of the tree.

Whether one has in mind the question of how the whole
cambium, normally not reproductive, becomes endowed with
reproductive power; or the negative side of the question,
that of why it should not be reproductive under normal
conditions, there is no way of reasoning adequately about
the causes of the phenomena without bringing in the tree
as a structural and functional whole. The redwood tree
as a whole is essential to a causal explanation of the ca-
pacity of its cambium tissue. Efforts to escape such a rec-
ognition by resorting to conceptions like those of germ-
plasm and plantagens is unmitigated sophistry.

The Individual Animal and Its Parts

So obvious is it that in the full-grown individual of any
of the higher animals the organs and parts are in some

40 The Unity of the Organism

measure an adaptation to one another and have some struc-
tural dependence upon and correlation with one another,
that it would be superfluous to enumerate the facts and di-
late on their significance. The subject constitutes no small
part of the older comparative anatomy and physiology.

Almost as obvious is it, too, that the major parts of such
animals are incapable of long-continued life when they are
severed from the whole. But the great capacity for con-
tinuance in the living state possessed by certain parts of
some classes of animals has attracted much attention, most-
ly because of the intrinsic physiological and morphological
importance of the phenomena themselves rather than of any
assumed support afforded by them to the doctrine of au-
tonomy of the parts in a strictly elementalistic sense. But
these and other facts of organ-independence have been used
as a groundwoi^k for certain elementalistic conceptions of
the organism which, viewed in their liistorical setting, are of
much broader interest. The historical setting to which I
refer goes back to a speculation by that primal elementalist
Empedocles, and may be called an organ-assembling theory.
The modern relatives of this old theory may be called ag-
gregational theories, and are typified by the conception that
the normal individual plant or animal is an affair of sym-
biosis or secondary union of previously independent organ-
isms. A concise statement of Empedocles' hypothesis is
found in the De Generatione Animalium of Aristotle (Book
I, 722^, 20) : "in the time of his 'Reign of Love' says he
[Empedocles], 'many heads sprang up without necks,' and
later on these isolated parts combined into animals."

Symbiosis, as illustrated by Davidson's speculation, means
a partnership between individual organisms of different
species so intimate as to make each member of the combina-
tion really dependent to some extent on the other. A con-
siderable number of such cases are now known in both bot-
any and zoology. Perhaps the most striking example is

The Organism and its Major Parts 41

that of the partnership between an alga and a fungus to
make a Hchen. The kinsliip between such a speculation as
that of Empedocles concerning the origin of the individual
and the modern speculation which would have the individual
arise sjmbiotically is unmistakable. The most important
likeness between the two conceptions is the fact that both
are fundamentally wow-evolutional. The isolated heads,
necks, legs and arms of the ancient Greek, like the genn-
cells and germ-buds of the modern Englishman, are just
taken because they are necessary for the particular specu-
lation. The question of how heads and legs and of how
tree germ-cells and germ-buds arose in the first instance is
not raised, or if it were it could be answered in accordance
with the basal principle involved, only by assuming another
and another and another set of elements of the same kind,
ad infinitum. In a word, the theory really contains no pro-
vision in a truly organic sense for transformation, which is
the very essence of the conception of organic evolution. It
should be noticed that the principles of Love and Hate ap-
pealed to by Empedocles and that of struggle and survival
appealed to by neo-Darwinians are held to explain not the
origin of the heads, legs, etc., or of the gerai-cells and germ-
buds, but the origin of actual animals and plants from the
respective elements once the elements are at hand. In a
word, expressing the limitations on this mode of theorizing
in the familiar language of Darwinism proper i^not neo-
Dainv^inism), the natural selection hypothesis does not pre-
tend to explain the origin of variations and variants, but
assumes them. What we are bound to see if we look at the
relevant facts squarely is that the doctrine of organic evo-
lution involves the conception of ancestry as fundamentally
as it does that of progeny. Observation finds organisms
produced hy parents no less indubitably and inevitably than
it finds them giving origin to progeny, so that the effort
constantly recurring in recent biology to find ultimate se-

42 The Unit?/ of lire Orgainsm

curity in something or other to which the word genesis
can be attached, but which can yet be conceived as not sub-
ject to transfgrmation, is everywhere hostile in a funda-
mental sense to the descent theory.

The latest manifestation of this hostility is the gene or
factor theory of the ultra-Mendelians among present-day
geneticists. The gene as conceived in the genotype theory
turns out on close inspection to be still another something-
or-other, which though not itself transformable can explain
transformation in something else, and which has been ap-
pealed to by generation after generation of elemental-
minded theorizers about the origin of living beings, from the
ancient Grecian period at least. Jennings, one of the ablest
of the experimental geneticists, and one vf\\o has a genuine
regard for the visible as contrasted with the invisible and
hypothetical data of organic genesis, has lately pointed out
the essentially non-evolutionary character of the genotype
theory. "The whole conception," he rightly says, "is in
its essential nature static ; alteration does not fit into the
scheme." ^ We shall have occasion to consider this new
phase of the non-transformism in other connections. Our
purpose in referring to it here is merely to point out where
it belongs in the general scheme of genetic theorizing when
this scheme is viewed historically. Biology at present needs
few things more sorely than a system of reasoning which
shall not beget in students the mental habit of allowing re-
condite concepts and postulates and strange words to cast
every-day, familiar facts into outer darkness. One of the
most obvious and indubitable facts about all organic de-
velopment is transformation. The development of a chick
from a hen's egg is accomplished not merel}^ by a great in-
crease in size, but by the profoundest sort of transforma-
tion, this being deployed, as one may say, through a long
series of stages grading insensibly one into another. And
so with every other ontogeny, animal ontogen^^ especially.

The Orgfivism and its Major Parts 43

The working out of these innumerable transformational
stages constitutes the science of embryogenetics.

This transformational character of individual develop-
ment, or ontogenesis, is even more startling, and in some
ways confusing, in certain of tlie lower animals like the
coral polyps, where secondary individuals arQ produced
asexually but do not become whollv severed from the stock
or colony. But each multiple animal, as these may be called,
is a single germ-cell in the earliest stage of its life, and this
alone is proof of a certain measure of individuality of the
whole "colony" produced from the same egg. Indeed, some
zoologists, Huxley for instance '* have used this as the sole
or chief criterion of organic individuality, and have defined
the individual as all that arises from a single germ-cell.
There can be no doubt about the validity and usefulness of
this conception as one criterion of individuality, even though
it does not constitute a basis for a complete definition. An
exceedingly fertile field of zoological research is that of the
varying degrees and exact character of functional as well
as developmental integration in these metagenetically built-
up, loose animal individualities. Much is already known
on the subject, but very much is not known, and to extend
knowledge in this field is one of the urgent needs of zoology.
The subject received much more attention, relatively, two
or three decades ago than it does now^ ; so that few of the
investigations on which he have to rely have had the benefit
of the best technical methods. We may confidently antici-
pate that when the later technique of studies on neuro-mus-
cular stimulus and response and on internal secretions are
applied to metagenetic group-individuals, such as are found
in many of the coelenterates and in some of the tunicates,
much new light will be thrown on the interrelationship of
the members and organs in these poorly unified individuals.

But — and the point is cardinal for us — no matter how
much or what new knowledge we get as to the members and

44 The Viiity of the Organism

their relations to one another in these individuals, we are
sure that that knowledge will not militate in the least against
the reality of the individuals, nor against the fact that every
individual has some measure of unity, of integratedness,
structural, functional and developmental.

REFERENCE INDEX

I'

1. Pfeffer 18 6. Davidson 407

Q. Pfeffer 27 7. Davidson 405

3. Schwann and Schleiden.. 258 S.Jennings ('17) 283

4. Schwann and Schleiden.. 259 9. Huxley ('52) 146

5. Schwann and Schleiden . . 261

Chapter III

THE ANIMAL ORGANISM AND ITS GERM-LAYERS

The Germ-layers, Their Role In Development, and the

Germ-layer Theory

^^TRICT fidelity to the natural sequences of biological
^^ knowledge as viewed in this work would not permit us
to introduce at this early stage of our discussion such a
subject as that of germ-layers, or indeed any other purely
developmental aspect of the organism, but would require us
to deal more fully than we yet have with the completed or-
ganism. However, our general attitude having much of the
pragmatic about it will be broadly tolerant in the matter of
adapting methods to ends sought. This way of beginning
is chosen for the two-fold reason that in this domain my
own researches first came upon facts which contributed
very largely to the ideas underlying this whole undertaking,
and also that these and kindred facts constitute some of the
most striking evidence we have of the ability of the organism
to gain its developmental ends in unusual ways when the
usual ways chance to be obstructed — evidence, in other
words, of the domination of the organism as a totality over
its parts.

From its very beginning with Wolff and von Baer, mod-
ern embryology has recognized that animal embryos pass
through a stage in which the body consists of little more
than unifomi layers of cells, first one, then two, then three,
and finally, in several classes of animals, four ; these being
disposed one inside the other and more or less regularly

45 . ,

46 The Unity of the Organism

concentric. From these layers all the organs and tissues
are developed by a great variety of unequal thickenings and
foldings and concentrations and cellular differentiations.
Details are not necessary for our purpose. As expressed by
one standard textbook of embryology, these layers are as
a rule "structural units of a higher order than the cells."
"Primary organs of the animal body" is another term ap-
plied to them. The appropriateness of the descriptive term
"germinal" applied to these layers is found in the fact that
the tissues and organs are generated from them.

The passage of the embryos of so many different animals
through this layered condition makes the phenomenon a law
of animal ontogeny or individual development of wide ap-
plicability and this law, looked at from the standpoint of
the full-layered stage, is found to reach in both directions,
i.e., backward to the mode of origin of the layers from the
single undivided egg-stage of the organism, and forward to
the mode of origin of the tissues and organs from the layers.
Because of the great measure of uniformity among many
groups of animals which pervades the passage of the em-
byro from the egg-stage to the full-layered stage, embry-
ologists have been able to recognize and so name several
stages, the descriptions of which are in many cases very
clear and precise. The best defined of these are the morula
or cell-cluster stage, the blastula or one-layer stage, and the
gastrula or two-layer stage.

On the other hand, looking from the full-layered stage
toward the completed organism, a dominant uniformity in
developmental procedure, i.e., a conspicuous law of onto-
genesis, is seen in the part contributed by each layer to the
completed animal. Since it is this aspect of the matter that
particularly concerns us, we must go into a little more
detail. As laid down in the standard text-books of embry-
ology, three layers are recognized, namely the outermost,
called the ectoderm; the middle, called the mesoderm (in

The Animal Organism and its Germ-Layers 47

nianj groups split into two, thus making a four-layered
stage) ; and the innermost, called the endoderm. The deriva-
tives of these layers, as typically stated, are : From the
ectoderm, "The epidermis and its appendages, hairs, nails,
epidermal glands, and the enamel of the teeth. The nmcous
membrane lining the mouth and the nasal cavities, as well
as that lining the lower part of the rectum. The nervous
system and the nervous elements of the sense-organs, to-
gether with the lens of the eye." From the endoderm: "The
mucous membrane lining the digestive tract in general, to-
gether with the epithelium of the various glands associated
with it, such as the liver and pancreas. The lining epithe-
lium of the larynx, trachea, and lungs. The epithelium of
the bladder and urethra." From the mesoderm: "The vari-
ous connective tissues, including bone and the teeth (except
the enamel). The muscles, both striated and non-striated.
The circulatory system, including the blood itself and the
lymphatic system. The lining membrane of the serous cavi-
ties of the body. The kidneys and ureters. The organs of
reproduction." ^

The summary here given is taken from The Development
of the Human Body, by J. Playfair McMurrich, and conse-
quently has special application to man ; but it is a presen-
tation of what is usually understood to be contained in the
germ-layer theory applicable to all the metazoa with cer-
tain general modifications for the groups like the coelenter-
ata which never advance to the three-layered condition. As
thus treated the germ-layers are structures as indubitably
as are bones or muscles or feet or hands or brains ; and the
now unquestioned fact that they are so alike in both struc-
ture and relations in so great a range of animals, and give
rise with such constancy to the corresponding parts of
the completed animals, has been and ever must be of great
importance for the interpretation and comprehension of the
vast complexity of animal structure. Says one of the fore-

48 The Unity of the Organism

most embryologists : "As our knowledge of the development
from the germ-layers has grown, we have learned with ever-
increasing certainty that each germ-layer has its specific
role to play." ^

Are Germ-layers Developmental Organs and Subservient to
the Developmental Requirements of the Organism?

But after all this has been fully and gladly granted, there
still remains much to be said concerning the deeper biologi-
cal meaning of the germ-layers, and the different attitudes
of mind which different biologists may assume, indeed do
assume, toward these layers. What we have to offer on this
subject will be from the standpoint of the difference bet-
tween the elemental and the organismal ways of looking at
biological phenomena generally. This difference may be
brought out by asking, does the obviously very general rule
of origin of the tissues and organs from the different layers
hold with genuine universality, that is, in all animals in
which the three (or four) layers occur, and under all cir-
cumstances of development in every animal .^^ Or, putting
essentially the same question, but modified so as to show
more clearly its relevancy to the organismal and elemental
standpoints : are the germ-layers, when looked at as "struc-
tural units" or elements "of a higher order than cells" so
fundamentally independent of one another and of the or-
ganism as a whole that they always and under all conditions
must give rise to just the tissues and parts typically arising
from them, and nothing else? Or, shifting the point of view
a little : has the organism, as such, needs and abilities so
paramount that it is able to realize these needs by modi-
fying to any extent the developmental course usual to the
gorni-layers?

The Animal Organism and its Germ-Layers 49

A Negative Answer to the Question in the Last Section
Expected of Element alist Biology

Any one who perceives the essence of elementalism and
so has seen that it perforce implies a denial of causal
power of the whole organism oA^er its parts in development
will foresee what answer biology as strongly elementalist as
the science has been in the recent period wall be likely to give
to these questions. It will not be satisfied with basing its
expectation that an organ or tissue has arisen from a par-
ticular germ-layer solely on the fact that in all hitherto
obsers^ed cases it has so arisen. The contention may be ex-
pected that the independence and autocracy of the layers
are in no way subject to modification to meet the require-
ments of the organism as a unit: that in case of conflict
between the needs of the organism as such and the proper
powers of the layers, the organism must accommodate itself
to the layers if any accommodating is to be done. As a
matter of fact the germ-layer theory has been defended with
great vigor in just this hard-and-fast way. Nerve tissue
must arise from ectoderm if it comes into existence at all.
Under no circumstances is it permissible to believe it to have
arisen from either of the other layers. Muscle tissue must
arise from mesoderm (or mesenchyme) or not at all; and
so on, according to this way of viewing developmental phe-
nomena. Numerous biologists say in substance that the
entire teaching of embryology, anatomy, histology, and
pathology, should be based on the doctrine of the germ-
layers.

Evidence That Germ-Layers Are Thus Subservient to the

Organism

This brings us to the facts previously alluded to as
having played so considerable a part in genex'ating the sys-

N

50 The Unity of the Organism

tern of ideas set forth in this treatise. Put into a nutshell,
the case is one in which the ontogeny or individual develop-
ment being much out of the ordinary, several of the germ-
layer relationships prevailing in ordinar'y ontogeny are
profoundly modified, the end-results being the same as that
resulting from an ordinary development. To be explicit
on a single point, an instance is presented in which the
nervous s} stem arises not from the ectoderm in accordance
with the general rule, but from the endoderm, this profound
deviation from the typical being explicable, seemingly, from
the generally different entogenetic course followed in blasto-
genesis. The case, well known to embryologists but insuf-
ficiently heeded, is one of bud propagation in some of the
compound ascidians. I was not the first to observe the
uniqueness in this form of development ; but since in one of
the instances studied by me the facts are probably clearer
than in any other that has been examined, it will be best
to present in the barest outline only, the evidence furnished
by this one case. Full details are in my memoir.^

{a) Evidence From Bud Propagation in Compound Ascidians

We will confine our attention almost entirely to the one
species, Goodsiria dura (according to the later classifica-
tion Metandrocarpa dura), an abundant species on the
coast of California. To understand the particular points
with which we are concerned, it Avill be necessary to say a
few words about bud formation and development in this
grou]^. The buds are not produced by "Stolons" as they
are in most bud-propagating ascidians, but each blasto-
zooid, as the bud-individuals are called, arises separately
and directly from its parent zooid. It forms at the anterior
end of the parent and in such a way as to be two-layered
from the very first, the layers being ectoderm or outer
laver^, and endoderm or inner layer. The bud when first

The Animal Organism and its Germ-Layers 51

separated from the parent is exceedingly simple, being an
almost perfect sphere. The layers are, at this stage, only
a single cell thick and are quite uniform throughout. The
endodermal layer, or "inner vesicle" as it is spoken of
technically, is separated from the ectoderm or "outer ves-
icle" by a wide space all around. Because of these simple
conditions the investigator is able to make out with great
certainty most of the events in the transformation of the
vesiculate stage into the completed organism. The first
differentiating step noticeable in the inner vesicle consists
of a somewhat elongated outpocketing of the wall of the
dorsal side of tlie vesicle. What occurs later in connection
with this outpocketing may be stated by quoting from the
original paper: "Simultaneously with the closing off from
the inner vesicle from before backward of the hypophyseal
duct, the ganglion becomes differentiated in the same order
from the cell mass that forms the last connection between
the duct and the vesicle." The "ganglion" is, it should
be stated, the beginning of the whole central nervous system
of these animals. My observations being a confirmation and
extension of those by other zoologists on other species, not-
ably by the older zoologists Giard and Kowalevsky, and in
the period of recent methods, by Hjort, there can be no
question that the nervous system arises in some gemmipar-
ously produced ascidians, from the inner germ-layer whereas
in individuals of the same sjjecies produced from eggs, the
nervous system arises as it does in the vast majority of
animals from the outer germ-layer.

The only point that has been or can be made against
this as an instance of complete transfer of the place of
origin of the nervous system from one germ-layer to another,
is that the "inner vesicle" of the bud is not in reality endo-
derm but ectoderm, this resulting from the manner of de-
velopment in the parent of the layer from which the inner
vesicle originates. There i§ considerable ground for this

52 The Unity of the Organism

interpretation of the inner vesicle so far as Botryllus is
concerned, but much ground against it for several other
species. Even though the Irishism that the endoderm of the
bud is not endoderm but ectoderm, that is, that the inner-
derm is really an outer-derm be accepted as true, the real
issue so far as this discussion is concerned remains unaf-
fected. Whatever the inner layer should be considered as
judged by its origin, judged by its developmental potency
its endodermal nature is beyond question, for nothing is
more certain than that it gives rise to the main part of the
alimentary system as, in accordance with the general rule,
it ought to. The kernel of the matter is that here is a case
in which both the digestive organ and the ner\^ous system
arise from the same germ-layer, which is contrary to the
almost universal rule. What that layer should be called
matters not, as we are now looking at the situation.

We can see, as intimated at the outset, the probable im-
mediate cause of this fundamental modification of the on-
togeny. Hjort was the first to dwell adequately on this
aspect of the subject. But since my own conclusions were
drawn before his memoir reached me and so were wholly in-
dependent of his, it will be permissible to present the ex-
planation in my own way. This I will do in the original
language slightly modified. The ectoderm of the ascidian
bud, even at its very beginning, is part and parcel of the
ectoderm of the parent, particularly in Goodsiria and Bot-
ryllus where, in the absence of a stolon, the budding region
is enveloped in the cellulose tunic characteristic of ail
tunicata. This is equivalent to saying that the ectodeiTn
of the bud is not, even at the very outset, an embryonic
structure at all. It is, on the contrary, a differentiated
organ whose function is, as in the parent, to secrete the
cellulose matrix of the outer tunic. In the performance of
this function, it would appear to be vigorously and con-
sistently active, for the matrix is large in quantity and prob-

The Ammal Organifim and its Germ-Layers 53

ably constantly renewed. This production may, as Hjort
liad well contended, be compared with the production of
horn, or still better, of cartilage matrix by the cells appro-
priate to these substances. So the ectoderm has a well-
established physiological role to play from the very earliest
stage in the career of the bud. Quite otherwise is it with
the endoderm. It is difficult to see how a structure could be
more favorabl}'^ circumstanced for retaining, so far as its
physiological relation to the organism as a whole is con-
cerned, an undifferentiated state than is the case with this
one. It is wholly protected from contact with the external
world by being enclosed in the ectodermic vesicle; further-
more, it has little or nothing to do with the preparation of
its own nutriment, since it is constantly and completely
bathed in the maternal blood. So why should not the pro-
duction of structures which in embryogenesis belong to the
ectoderm, be here transferred to the endoderm .^^ And so
it is.

This conclusion is the more justified when one considers
how differently circumstanced are the two layers in the
embryo. Here the incipient nervous system arises from
the ectodeiTn while the layer is in a strictly embryonic stage
and before the endoderm has freed itself from the rich store
of yolk material which is passed on to it from the egg. We
seem to have here an instance in nature where the later
functional requirements of the organism as such have run
counter to the way in which, through the operation of re-
moter hereditary influences alone, development would pro-
ceed; and the former have proved more powerful.

(b) Evidence From Bud Propagation in Bryozoa

Defiance of the germ-layer doctrine is by no means re-
stricted to the gemmiparous ascidians. In bud propagation
in bryozoa, a widely different group, departure from the

54 The Unity of the Organism

rule is no less certain and fundamental. The developmental
processes in these animals are somewhat more obscure at
several crucial points than in the ascidians, and there has
been proportionately more diversity of interpretation among
investigators. Nearly all, however, from H. Nitsche who
first pointed out the anomalies here presented, to the latest
students in this field, Calvet and Romer, agree to the extent
of recognizing that the layers of the buds in these animals
do not conform to the germ-layer scheme that prevails so
widely in ontogenesis starting from the ^gg.

A good summary of the view most commonly held by
specialists in this field is given by Harmer.* "There is
good reason for believing that in polyzoa the polypide-bud is
developed entirely from ectoderm and mesoderm. This bud is
a two-layered vesicle, attached to the inner side of the body-
wall. Its inner layer is derived from the ectoderm, which at
first projects into the body-cavity in the form of a solid
knob surrounded by mesoderm-cells. A cavity appears in
the inner, ectodermic mass, and the upper part of the
vesicle so developed becomes excessively thin, forming the
tentacle-sliciith, which is always in the condition of retrac-
tion. The lower part becomes thicker; its inner layer gives
rise to tlie lining of tlie alimentary canal, to the nervous
system, and to the outer epithelium of the tentacles, which
grow out into the tentacle sheath. The outer layer gives
rise to the mcsodermic structures, such as the muscles, con-
nective tissue, and generative organs." Although this de-
scription may not give a very clear picture to readers un-
acquainted witli the structure and development of the bry-
ozoa, the point of central importance to tliis discussion is
clear enough : The outer layer of the body wall gives rise
to the inner layer of the bud, and from tliis layer is pro-
duced the lining of the alimentary canal, and the entire
nervous system. No matter what the outer layer of the
body-wall and its continuation as inner layer of the undif-

The Animal Organism and its Germ-Layers 55

ferentiated bud be called, the germ-layer doctrine is set
at nauglit since one laj^er gives rise to both the digestive
epithelium and the nerve ganglion.

As a matter of fact, this statement falls short of reveal-
ing the full measure of confusion as regards germ-layers
wliich prevails in these animals, since one layer, the outer
of the body-wall, contributes to every essential part of the
polypide in some species. Thus Calvert shows that in Bug-
ula sahaiieri cells are set free into the body cavity from the
outer layer at the time that the knob of cells of that layer,
which is the foundation of the bud, makes its appearance,
and these freed cells assemble to produce, in part at least,
the layer on the surface of the knob usually called the meso-
derm of the bud. And this observation Romer has confirmed
"mit aller bestimmtheit" for another species, Aleyonidium
mytile. It seems that the entire polypide may be formed
from a single germ-layer, namely the ectoderm.

The reader should not fail to compare what is here set
forth about bryozoan budding with what we learned about
ascidian budding to the extent of noticing that whereas in the
ascidian we found the inner layer (no matter whether called
endoderm or by some other name) producing nearly the entire
zooid ; in the bryozoan the outer layer (no matter by what
name called) produces in some cases, nearly the entire poly-
pide.

If it be asked whether the principle invoked to explain
why the ectoderm of the ascidian bud takes so small a part
in producing the future animal (namely, that of greater
functional specialization and activity of the ectoderm than
of the endodoiTn at the place of origin of the bud,) be also
available for explaining the reverse order in layer con-
tribution to the bud-produced animal in the bryozoan, no
very satisfactory answer is forthcoming from the infor-
mation we now possess. Two facts may be adverted to, how-
ever, which suggest that the same principle is operative in

56 The Unity of the Organism

the two cases. In the first place, it may be reasonably
doubted whether the thin cuticular covering produced by the
outer layer of the body wall in the bryozoan involves as great
a degree of specialization either in nature of product or in
extent of activity as does the far more voluminous "test"
material produced by the ascidian ectoderm. In the second
place, the so-called mesodermal layer of the bryozoan body-
wall surely has no such direct and intimate connection with
the parent polypides, i.e. the other members of the colony,
as does the "cloison" or inner tube of the ascidian colony
from which the inner vesicle of the bud is produced. We may
consequently surmise that in the bryozoan as in the ascidian
the layer that is most available because of being least fully
occupied with activities pertaining to the parent organism
is most largely drawn upon in bud propagation. A kind
of balance between the functions of growth and maintenance
on the one hand, and propagation on the other, is struck in
each case although this implicates the germ-layers in op-
posite ways in two cases.

^'

The Animal Organism and its Germ-Layers 57

(c) Evidence from the Regeneration of the Lens of the

Amphibian Eye

The supremacy of the organism over its germ-layer is
shown in no way more strikingly than in facts brought to
light in some of the researches of late years on animal re-
generation. Perhaps the case at once the best established
and most discussed is that of the way the extirpated lens
of the eye is renewed in some amphibians. Referring to the
parts enumerated above as arising from each of the three
germ-layers in vertebrates, we note that the lens is assigned
to the ectodeiTn. To be a little more explicit, this member
originates from the outermost epithelial layer of the head
of the embryo. Hardly any point in vertebrate embryology
is easier to demonstrate than this. Experiments have
proved, however, that when a new lens is produced in a full
grown animal, to take the place of one that has been de-
stroyed, this does not arise as did the original from the
surface epithelium but from the edge of the iris, that is,
from a part of the eye itself. The discoverer, Collucci, did
not consider it to be out of accord with the genn-layer doc-
trine because the iris is the highly modified rim of the orig-
inal optic cup, which is derived from the cerebral vesicle,
which in its turn is derived from the ectoderm, so that in a
round-about way the iris is an ectoderaial product. The
fact remains, nevertheless, that the mode of origination of
the new lens is so radically different from that of the old
that to regard it as sufficiently dealt with when attention
is called to the fact that it conforms in a way to the genn-
layer doctrine is an impressive illustration of the evil effects
of subserviency to a theory — of the inhibiting effect of such
a mental attitude upon interest and observation. Later
investigators, notably G. Wolff, A. Fischel, and W. N.
Lewis, have shown how much more there is to the phenomena
of development and regeneration of the vertebrate eye than

58 The Unity of the Organism

the single matter of reference of the several parts to their
appropriate germ-layers. The work of these students car-
ries the subject into other fields, particularly those of re-
generation, and of formative stimulation.

The Germ-Layer Theory and the Germ-Plasm Theory

This discussion of the germ-layers will terminate with a
section on the part played by the layers in producing the sex-
cells where propagation is by the sexual method. This ter-
mination will also be the culmination in point of importance,
since it will lead as well into the examination, to be con-
tinued in other sections and chapters, of the results and
the general modes of reasoning of the Weismannian school of
speculation about heredity.

The manner of involvement of the layers in the specula-
tions of this school becomes apparent on a moment's reflec-
tion. As is widely known, Weismann and his adlierents
conceive a particular substance known as germ-plasm to
which all the phenomena of heredity are due, this being fun-
damentally different from and independent of the great mass
of substance called by them somatoplasm which makes up
tlie bodies of organisms. Not only is this germ-plasm quite
apart from the somatoplasm in a given individual plant or
animal, but it passes along from parent to offspring, gen-
eration after generation, wholly uncontaminated, as one may
say, by contact with the somatoplasm. This supposition of
a propagative stream or string has been elaborated into
what is known as the doctrine of the "continuity of the
germ-plasm." A point fundamental to the doctrine is that
not merely the germ-plasm may pass over in this way from
parent to offspring, or that so7ne portion of it always does
thus pass, but that all the germ-plasm the offspring ever has
comes from this source. Otherwise expressed, the doctrine
is tliat germ-plasm is never produced anew in a strict sense.

The Animal Organism and its Germ-Layers 59

Weismann is sufficiently explicit on this point. Not only
does he assume that germ-plasm cannot be produced by the
transformation of somatoplasm, but he holds it cannot be
produced in any other way. Touching the more special case
we read : "All these facts support the assumption that so-
matic idioplasm is never transformed into germ-plasm, and
this conclusion forms the basis of the theory of the compo-
sition of the germ-plasm as propounded here." ^

A fairly typical expression of the author's all-embracing
denial of new germ-plasm is the following: "The off-
spring owes its origin to a peculiar substance of extremely
complicated structure, viz.: the 'gcrni-phism.' This sub-
stance can never he formed anew; it can only grow, multiply,
and be transmitted from, one generation to another.'* ^ A
form of expression much used by Weismann particularly in
his later writings, which somewliat disguises though does
not surrender the main point, is that of "primary con-
stituents" of the germinal substance. Thus in his discus-
sion of the germ-plasm doctrine in his last extensive work,
The Evolution Theory, we find "I am forced to see in this
fact alone [that of metamorphosis in ontogeny] an invalida-
tion of all epigenetic theories of development, that is of all
theories which assume a germ-substance without primary
constituents, which can produce the complicated body solely
by varying step by step under the influence of external in-
fluences, both extra- and intra-somatic."*^ *

The Exact Mode of Involvement of the Germ-plasm Theory

in the Germ-Layer Theory

We return now to the immediate point, namely that of
the way the germ-plasm doctrine involves the genn-layers.

* While this is not the place to point out in detail the far-reaching
consequences of this assumed impossibility of new formation in or-
ganic evolution, much less to show the subtle fallacy which it involves,
the general subject is so important and will loom up so greatly in our
enterprise as a whole, that I would wish to get it well into the read-
er's attention even at this early stage of our progress.

60 The Unity of the Organism

Since it is the main office of the sex-cells to carry the sup-
posed germ-plasm, and since germ-plasm cannot be distin-
guished from somatoplasm by direct observation, and since
sex-cells are not present in the individual organism of most
species up to and including the layered stage of its life, the
question of exactly how and where the sex-cells arise will
be seen to involve the question of which of the layers they
arise in. The problem may be stated more explicitly as
follows : Where is the germ-plasm between the time when the
germ-cell which is the beginning of a new individual disap-
pears through division, and the appearance of new germ-
cells within that individual, as the first stage in the life of
an individual of the next generation? Or, stating the ques-
tion still more explicitly, by what means and by what route
does the assumed pre-existent germ-plasm get from its orig-
inal place in the sex-cell which produces a given individual
to the sex-cell produced by that individual?

Weismann'*s Studies on the Origin of Germ-Cells in Hydroids

Our purpose restricts our examination of the question
stated in this general form, to the particular question of
where and how (relative to the germ-layer) the sex-cells
arise in an individual. Since Weismann elaborated his solu-
tion of the problem largely on the basis of phenomena pre-
sented by the Hydromedusae, many of which phenomena
were brought to light by his own researches, we shall give
these animals the central place in our examination. In the
first place, the fact should be clearly understood that Weis-
mann has never contended that a direct observable continu-
ity between the parent sex-cell and the sex-cells of the off-
spring occurs in this group of animals. On the contrary,
he fully recognizes, as do all students of these animals who
have occupied themselves with this particular point, that
a wide gap separates the parental from the filial sex-cells.

The Animal Organism a7id its Germ-Layers 61

The very earliest recognizable sex-cells occur in the one or
the other of the two body layers ; that is, in the ectoderm
or the endodenn of the fully developed animal. Since Weis-
mann's theory denies the possibility of the origin of the
sex-cells, or at least the essential part of these, the germ-
plasm, from somatoplasm, his theory of sex-cell production
in such animals as the hydroids must contain two quite
distinct parts : one as to the route by which the germ-plasm
travels from parental to filial sex-cell, and the other as to
the force or forces by whicli the journey is accomplished.

The first part of the theory starts from the indubitable
facts that in those hydromedus.x' having a free-swimming
medusa, or jelly fish, the sex-cells are borne by this and not
by the polyp; that these cells do not as a rule arise in the
medusa itself, but somewhere in the colony of polyps, from
which location they migrate (in some cases for considerable
distances) to the buds whicli later develop into medusae; and
that in the majority of species which have been examined
with reference to the point, the mature sex-cells are found
in the ectoderm and not in the endodenn. On the basis of
these facts Weismann thought out a very elaborate and in-
genious theory by means of which through various assump-
tions about the evolutionary history of the hydromedusa?,
he was able to make the facts seem not only to harmonize
with, but to support positively the doctrine of the con-
tinuity of the germ-plasm. Into that part of the theory
which concerns the phylogenetic relation of the medusoid to
the polypoid forms of the group, we need not. go further
than to say that through his speculations on this point he
was able to provide a Marschronte or germinal highway or
germ track from the parent sex-cell to the filial sex-cell. The
question of where this Marschronte runs, with reference to
the germ-layers is what immediately concerns us.

According to the theory, the germ-plasm of the parental
sex-cells passes first into certain cells of the ectoderm of

62 ^ The Unity of the Organism

the polyp-generation from which place those cells make their
journey to the ectoderm of the medusa, usually to some
portion of it connected with the manubrium or digestive
part of the animal. But — and here we come to the real
point of the present discussion — since sex-cells are found by
actual observation in the endoderm, in several genera and
species, the theory is that the Marschroute lies first in the
ectoderm, then passes over into the endoderm and returns
later to the final goal of the sex-cells in the manubrial ec-
toderm. The ectoderm therefore is the home by natural-
ization, so to say, of the germ-plasm in these animals ; it is
originally planted there from the parental egg and finally
matured there. As will be seen from what has previously
been said, the kernel of the theory is to account for the
positions and movements of the sex-cells in accordance with
the supposition that their most essential part, their genri-
plasm, cannot be formed anew from somatoplasm of any
sort either entodcrmal or ectodermal, but must come over
in direct continuity from the germ-plasm of the parental
egg. The reason why the theory is so insistent on ascrib-
ing the sex-cells to the ectoderai is that it supposes that
originally in the evolutional history of the group,, the germ-
plasm destined for the next generation of sex-cells was
lodged in the ectoderm, and that this predestined it to that
layer for all time.

Inconclusive ness of Weismanns Results Shown hy Goette

and Others

We have now to inquire how it has fared in later research
with the numerous subsidiary hypotheses which enter into
this complex tlieory of germ-plasm behavior in these organ-
isms. Alexander Goette has lately gone over almost the
entire grounds covered by Weismann in tlio monograph al-
ready mentioned, and his i*esults and general conclusions

The Animal Organism and its Germ-Layers 63

are interesting in the liighest degree. It would be impossible,
even were it desirable, to review the memoir exhaustively.
As to the most general aspect of it, it will suffice to say that
Goette takes issue with nearly every one of Weismann's most
important conceptions. The liypothesis that the gonophores
are in all cases degenerate medusae; the hypothesis of Mar-
scliroute (of hard and fast germ tracks); the hypothesis
of entirely independent activity of the sex-cells in migration
supported by the suggestion that the cells migrate by virtue
of a "homing instinct" something like that supposed by
some naturalists to be possessed by migratory birds ; and
finally and most relevant to the present discussion, the hy-
pothesis which denies the actual origin of the germ cells in
the endodenn : all these hypotheses and others which could
be mentioned, Goette holds to be either in positive opposition
to the observed facts or not necessitated by them.

It would be contended on the Weismannian mode of theor-
izing that since the issue is mainh^ one of interpreting facts,
and not of what the facts are, Goette's views are entitled
to no more weight than are Weismann's, and so do not con-
stitute a disproof of the hypotheses in question. As this con-
tention comes very near to the center of Weissmann's logical
procedure, we must look at it attentively. Assuming that
Weismann and Goette are equally endowed by nature and by
training as observational biologists (and I have no doubt
the great majority of unbiased zoologists who know the
work of the two men would allow this), it must be granted
that Goette as pitted against Weismann does not constitute
a disproof of the latter's hypotheses. But does this admis-
sion leave these hypotheses just where they were before
Goette's attack upon them? By no means. We may state
the case this way : Weismann observes a long series of facts
concerning the structure and development of a particular
group of animals, and on the basis of these and in the
interest of a theory of still more general scope, and of pre-

64 TJie Unity of the Organism

vious formulations, sets up a number of hypotheses. That
these are fully proved is not contended even by Weismann
himself: they are only given a good degree of plausibility
or probability. Then comes another investigator of equal
competency who goes over essentially the same ground and
reaches essentially the same factual results, but who does not
believe the hypotheses propounded by the first investigator
are supported by the facts. What can a third person legiti-
mately see in the total situation other than that whatever
probability was given the hypotheses by the one investigator
has been taken away from them by the other investigator?
So far as we have yet gone with our examination we are, I
think, compelled to recognize that as regards interpretation
of structure and reproduction in the hydromedusae, Goette's
work leaves the matter just where it was before Weismann
propounded his hypothesis. But we have not concluded the
inspection ; we have only considered Goette's w^ork in its re-
futational or destructive aspect. Whatever of positive re-
sults both as to observation and hypothesis he has to set
over against Weismann's must now be briefly considered.
And here we return to the matter in hand in this section,
that, namely, of the relation of the sex-cells to the germ-
layers.

Goette believes he has proved incontestably that the sex-
cells do arise in the endodervi in some species, so that Weis-
mann's assertion that in this group they always arise in the
ectodcnn is wrong. But of far greater importance, Goette
shows that not only the endodcrmal but also the ectodeiTnal
origin of the sex-cells is such as not to give the least warrant
for the hypothesis that any part of the cell (the supposed
germplasm being of course aimed at) does not arise by trans-
formation of the material of the layer in which they first
appear. And in this it seems to me he has made his case.
His description accompanied by numerous drawings of the
sex-cells in Corydendrium parasiticum, may be instanced

The Animal Organism and its Germ-Layers Q5

as a particularly clear case of the genuine transformation of
cndoderm cells into sex-cells. To be still more explicit, in
liis figure (115 plate V,) is shown a sex-cell so slightly differ-
ent from the neighboring cndoderm cells, and so related to
the surrounding cells, that no one would hesitate to conclude
that it had very recently arisen by division of one of the
cndoderm cells unless influenced by considerations other than
the evidence actually before his eyes. Exactly the same
conditions, he says, are observable in Clava, Sertularia, and
Sertularella; and he then remarks: "From these observ'^ations
it becomes unfair to assume that in other cases where germ
cells are found in the endoderm that they have wandered
from the ectoderm. Proof of tliis must be absolute." ^ The
full force of this remark is seen only when it is taken in
connection with Weismann's own statements about the sex-
cells of Corydendrium parasiticwm. He saw here no less
positively than did Goette, very young stages of the cells in
the endoderm ; but since, he says, he could not find the ab-
solutely first stages "the possibility of the ectodermal ori-
gin of the sex-cells is not excluded." ^ In other words, the
absence of absolute proof of the endodermal origin of the
cells is used to support the a priori conclusion that they
arise in the ectoderm ! So far as the observational evidence
in this specific case goes, it strongly supports, as Weismann
himself grants, the conclusion that the reproductive cells
arise in the endoderm, but since the evidence falls a little
short of finality it may be cast aside wholly in favor of
purely theoretical grounds for supposing the origin to be
elsewhere! Against this method of reasoning Goette
strongly protests, and every biologist who genuinely be-
lieves that speculative proof must yield to observational
proof when the two come into conflict, will say amen. And
when once one sees the extent to which Weismann's whole
system rests upon this method, and sees at the same time
how widely influential the system is, he will recognize that

66 The Unity of the Organism

it is hardly possible to overestimate the importance of cor-
recting the method and neutralising the evil it has wrought.

Weismanns Erroneous Conclusions Concerning the Origin
of Sex-Cells in Hydroids as an Example of the
Effect on the Observing Powers of the Germ-
Plasm Type of Speculation.

A striking example of the effect of this system of specula-
tion on the observing and reasoning faculties is afforded by
Weismann's way of viewing the part played by the genn-
layers in bud propagation in young animals. We might
have presented the case when we were dealing with budding
in ascidians and bryozoans, but as it implicates germ-cells
and germ-plasm more intimately than we were prepared for
at that time we speak of it here.

As pointed out above, Weismann's general interpretation
of the sex-cells in the hydromedusa^ led him to conceive that
the germ-plasm is lodged in the ectoderm in these animals.
This being so, he naturally concluded that his imaginary
bound C^gebu/nden*'), or unalterable, or accessory germ-
plasm set aside for bud propagation ("blastogenic germ-
plasm") must also be confined to the ectoderm. But ac-
cording to the various researches, both endoderm and ecto-
derm participate, as a rule, in giving origin to the bud.
What was to be done about this? Notice carefully what,
according to the system, would be a sufficient confirmation
of the theoretical view that buds really arise solely from
the ectoderm: To find one or a few instances in which the
buds do either certainly or probably begin in that layer, to
assume this to be the phylogenetically primitive condition,
and then to point out that in cases in which the two layers
undoubtedly enter into the bud in the earliest stage, the
"possibility is not excluded" that latent invisible germ-plasm
is present in the ectoderm, becomes active at the place where

The Animal Organism and its Germ-Layers 67

a bud is to form, iiiigratcs into the ciidoderin, and so ex-
plains the participation of the endoderni in bud production.

Goette's conclusions as to the actual endodernial origin
of sex-cells in the h^^droids are not unsupported by other
workers. Thus Tichoniiroff holds tiiat the sperm cells of
Eudendr'iurn aurentiwm arise in this layer, and C. W. Har-
gitt, who has devoted much time to the question, is unc^uali-
fied in his statements. He writes in a sunnnary presentation
of his results : "It may be said that while in Eudendrium
ramoswm and E. tenue the ova arise strictly in the endo-
derm, and never at any time find their way into the ectoderm,
in the species racemosum and disjxir these products are
found abundantly in both tissues." ^^ So the observations
seem conclusive that taking the group of hydromedusae as
a whole, the sex-cells arise in the ectoderm in some species
and in the endoderni in other species, and that this origina-
tion is by a transformation of substance in both cases from
what it was originally into that of the reproductive elements.
Indeed the power of the propagative function of the organ-
ism to start indifFerentl}' with either ectodermal or endo-
dermal material and reach the same end as seen in different
genera of the hydi^omedusa?, seems in some cases to extend
to different species of the same genus. "If one holds rigor-
ously to the facts," writes Goette, "he must in spite of all
hold to it as most probable that the Reims tcitte in different
species of End end riant, perhaps indeed in the same spe-
cies, changes." ^^

Finally, and as a cap-sheaf to the arguments here pre-
sented in favor of the view that sex-cells do arise genuinely
anew in each individual in the hydromedusse, it remains to be
shown that Weismann himself was really in accord with
Goette on this point when he wrote the monograph on the
origin of the sex-cells ; and that only later under the impul-
sion of his speculations about genn-plasm did he come to
repudiate this view. On page 284 of the monograph we find

68 The Unity of the Organism

the following: "After all this, there can be no doubt that the
germ cells may reach their differentiation and separation
from somatic cells only when the germ-layers have long since
been formed, and it is impossible to accept as a general law
the view of Xus.sbaum that sex cells are 'absolutely indepen-
dent of the germ layers.' So far as we can now see, the sex-
cells always arise in the hydroids from elements of one of the
germ-layers and they are not merely inclusions in a germ-
Iryqi' but are derivatives, are division products of it." ^^
Stripj^ed of all so})histry, how is it ])ossible to avoid seeing
that we have before us a clear case in which Weismann can
defend his doctrine of heredity at one of its most critical
points only })y making purely speculative considerations
supplant observational evidence which he himself produced
at an earlier period in his career?

The conception of an "hereditary substance" distinct
from a non-hereditary substance, by whatever name called,
and continuous from parent to offspring is contrary to the
observed facts of sexual reproduction in the hydromedus^e
as established by Weismann himself and by other and later
biologists of unquestioned competency and trustworthiness.
To this conclusion we are forced by an examination of the
available knowledge of the sex-cells in their relation to the
germ-layers in this group of organisms.

The Stronglij Oryanismal Implications, of Gocttc's Conclu-
sions on the Origin and Migration of Germ-
Cells in Hydroids

With this conclusion we return to the examination of the
constructive as contrasted with the destructive results of
Goette's research. We have sliown the most specific and im-
mediate of these as viewed from the standpoint of this sec-
tion on the organism and its germ-layers, that, namely,

The Amm(d Organism 4rid its Germ-Layers 60

wherein lie proves tlie actual origin of the sex-cells from
the endoderm. The only other positive result which I will
touch upon is that concerning the route and cause of
migration of the sex-cells from their place of origin to their
place of maturing. Goette denies that they have any single
road which is the same for all species, as contended by
Weismann. He affirms on the contrary, that at least four
paths are demonstrable, namely, the gastric endoderm; the
bases of the pouches of the radial canal ; the spadix ; and the
ectoderm of the manubrium. The kernel of Goette's con-
clusion on this subject, as opposed to Weismann's is, as I
understand, that the sex-cells arise widely scattered in the
parts and tissues of the polypoid colony, and that the de-
velopment of the gonads or sex glands consists in large part
in the drawing together or concentration of these dissemi-
nated elements, in some cases into buds that are to become
medusae proper, and in other cases where the medusoid is
wholly absent, into the gonophores or brood-sacs which are
outgrowths on the polyps. The diversity of the place of
origin precludes the possibility of any single "germ track."

Again Goette does not believe, as Weismann does, that
the journeyings of the sex-cells are due wholly to their own
independent activity , and considers the comparison of their
movements with those of migratory birds, and the ascrip-
tion to them of an innate instinct, to be entirely fanciful.
He holds, on the contrary, that these cells are largely car-
ried along passively by forces which originate in the sur-
rounding tissues and structures. His observations on the
cells of Podocoryne have, he says, been particularly con-
vincing that the wanderings are largely passive, and that
even where there is intrinsic movement this is indeterminate
as to direction, so that the final goal of the cells is in every
case determined chiefly by influences which lie outside the
cells themselves.

What the outside force is which Goette conceives to pro-

70 The Unity of the Organism

duce and direct the movements, we will hear him state in his
own words. It is "a result of the directive activity of the
definite and always similar developmental processes, . . .
therefore of those conditions which determine not only the
form of a body part, or organ, but also the transportation
and definitive emplacement of the separate particles. I re-
tain for this the expression 'form-conditions' used by me
several years ago."^^ Obviously this statement by Goette
carries us far beyond the bounds of germ-layers or even of
sex-cells and hereditary substance.

To the numerous biologists who would refuse to accept
Goette's "directing activity of the developmental process"
and his "Form-conditions" as an explanation of the mi-
gration of the sex-cells in tlie hydromedusse, because they
are vague and "unanalysed" conceptions, I put the question :
Are Weismann's conceptions of a wholly independent power
of movement possessed by the cells, and a deteniiination of
the route followed by them as an innate instinct of their an-
cestral home possessed by the cells, less vague and more
satisfactory because of the results of such an "analysis"?
Let it be granted for a moment that the cells perforai their
journeys by activities wholly their own, that they are com-
petent both to travel and to reach the end proper to them.
What then about the elements which enter into their make-
up, for surely no one would contend for a moment that they
are without elements.^ Shall we conceive that in moving they
do so by making use of their elements or parts in such fash-
ion as may be necessary to enable them to accomplish their
journeys? Or sliall we deny to the cells as such the power
of using their parts, but conceive that the parts are the
real seat of power — that in reality they move the cells instead
of being moved by the cells? If we accept the latter alter-
native, as in consistency witli tlie elementalist standpoint we
should have to, we shall be committed to either a never-
ending though ever-vanishing senes of biological elements.

The Animal Organism and its Germ-Layers 71

or to ultimate chemical elements endowed with, homing in-
stincts and the rest. Surely if either of these sub-alterna-
tives be accepted the analysis which goes no farther than
that of ascribing to the sex-cells power and instinct suffi-
cient to enable them to do what they do, would have gone
but a short way on its course and ought not to make any
pretence of being a complete explanation of the phenomena.
On the other hand, if we conceive that the sex-cells move
through the agency of their elements and are not merely
moved by means of these elements, why not as well allow that
the developing organism as such may move its cells to meet
its needs? As a purely logical matter there would be no
more hesitancy in admitting that the organism moves its
parts than in contending that the cell moves its parts, for
the difficulty of conceiving how the thing is done is no greater
in the one case than in the other. The only reason why the
conception that the cells migrate wholly by their own pow-
ers seems less vague, that is more analyzed, than the concep-
tion that the cells are moved by the growing organism, is
that in the first case a whole set of inevitable collateral phe-
nomena, that is those pertaining to the parts 'of the cells
themselves, is unconsciously excluded from the view. In
other words, the satisfaction felt by analysis of this sort
is an entirely spurious and illegitimate satisfaction begot-
ten of the fact that the analysis is false. It is a process
of searching for the factors involved in the complex of
phenomena under contemplation, but ignoring all excepting
a few of these factors. And this criticism of Weismann's
attempt to explain fully the migration of the sex-cells holds
for the attempt to explain on elementalist principles any
biological phenomena whatever.

I remarked above that as a "purely logical matter" there
is no more ground for refusing to believe the organism directs
the movements of the sex-cells than for refusinir to believe
the cells direct their own movements. It will not do to let

72 The Unity of the Organism

this remark go even in a tentative discussion of this vastly
important subject. If it is merely a question of equality
of claim upon belief as between the two conceptions so far
as logic is concerned, what is to determine the choice? Why
not accept the elemental as well as the organismal way of
interpreting the case if logically its claims be equal to that
of the latter? Because, I answer with emphasis, the observa-
tional evidence is stronger in favor of the organismal inter-
pretation. That is the sole legitimate ground on which to
rest the decision. Assuming, as we do, that Weismann and
Goette are equally competent and trustworthy investigators,
and basing the decision for the present on their results alone,
we are bound to recognize that Goette has brought forAvard
much more observational evidence that the migration of the
sex-cells is largely though not wholly passive than Weis-
mann has that it is wholly active.

Remarks on the Relation of Germ-Cells to Germ-Layers and

to the Organism Generally

Before taking leave of the concrete objects, germ-layers
and germ-cells, I speak of one aspect of the general results
of our examination which may escape the reader unless his
attention is specially directed to the matter. In all those
animals in which the sex-cells do not appear until the lay-
ered stage of the embryo is reached, and in which these cells
arise by a genuine transformation of cells of the layer, as
they do in hydromedusse, the layers are gemiinal in a very
fundamental sense, for it is in them that the transformations
begin which issue in the completed tissues and organs of all
sorts, the sexual tissues and organs with the rest. Viewed in
this light the germ-layers have, on the whole, gained rather
than lost in importance and interest, for while we are led
to deny the rigorous specificity to each particular layer as
to what may or may not arise from it that often constituted

The Animal Organism and its Germ-Lazjers 75

a part of the germ-layer theory, it is a great gain to have
perceived clearly that it is in the layered stage of the in-
dividual's life in many species that the next generation of
individuals takes its rise. However, it does not by any
means follow that because the sex-cells are born, as one
might say, at this early time in the life of the parent, they
are fully exem})t from parental influence during all the per-
iod intervening between the layered stage of the parent and
its stage of sexual maturity, that is, of final separation and
extrusion of the sex-cells.

It seems to me the fact that the sex-cells of even some
vertebrates are found at an early stage of embryonal life
embedded in one or another of the germ-layers at points far
removed from where the definitive germ glands will later ap-
pear, may signify just such influence. In other words, it
may be the meaning of the "precocious segregation," as it is
called, of germ-cells ought to be taken along with their wide
dissemination in the embryo, and interpreted as speaking
against and not for the fundamental isolation of the germ-
plasm.

The distribution of sex-cells in the early embryos of ver-
tebrates has been studied by several zoologists, among them
being C. H. Eigenmann and B. M. Allen. Allen's investiga-
tions are specially important because of their wide com-
parative scope. In The Origin of the Sex-Cells of Amia and
Lepidosteus he gives a set of useful diagrammatical com-
parative drawings showing the mode of origin of the sex-
cells from the endoderm of a reptile (Chrtjsomys), an am-
])hibian (Frog), and two fishes (Amia and Lepidosteus), but
reaffirms in his discussion the result that the cells arise in
the mesoderm in the tailed amphibians.

74 The Unity of the Organism

The Relatio7i of Ideas and Observations as Exemplified in
the Discussions of This Chapter

I would have this discussion stand as one example of the
general method of interpretation which underlies our whole
undertaking: while interpretation of biological phenomena
is wholly impossible without ideas, some of which take the
form of hypotheses and theories, equally true is it that
hypothesis and theory are wholly dependent upon observa-
tion for validity. To this every biologist in whatever field
of research and of whatever manner of thinking, would as-
sent. But I go farther and assert that no hypothesis is
proved, nor can be elevated to the rank of a general theory
or doctrine until it is brought into acdord with all relevant
and fully verified observational knowledge. To this no ele-
mentalist assents in practice even though he may in words.
Measured by this standard our final constructive discussion
will reveal the fact that such conceptions as those of Weis-
mann's germ-plasm and DeVries' pangens are not legitimate
scientific theories at all. They are not because they can be
maintained only by positively refusing to admit as evidence
many of the demonstrable relevant obsei^^ational facts.

REFERENCE INDEX

1. McMurrich 79 8. Goette 63

2. Minot 250 9. Weismann ('83) 42

3. Ritter ('96) 183 10. Hai-gitt 24^

4. Harmer 514 11. Goette 63

5. Weismann ('12) 190 12. Weismann ('83) 284

6. Weismann ('12) xiii 13. Goette 301

7. Weismann ('04) 400

Chapter IV

THE ORGANISM AND ITS CHEMISTRY

Standpomt of the Discussion that of the Evolutionary

Naturalist

I3HYSIOLOGISTS and biochemists are not forced into
^ contact with questions of organic evolution to any such
extent as are botanists and zoologists. Occupied as they
are in any particular investigation with relatively restricted
aspects of one or a few organisms, such matters as geogra-
phic distribution, geologic succession, abundance and variety
of individuals and species, adaptation, and so on, come to
their attention very little or not at all. But these are
exactly the problems with which the naturalist is occupied,
and they are at the same time the very building stones of
the evolution theory. This difference in interests and occu-
pations doubtless accounts for the fact that the great
evolutionists of history have been, without exception, natu-
ralists primarily. The three names that stand out with
mountain like conspicuousness among those who in modem
times have made the idea of evolution a household posses-
sion, Lamarck, Darwin, and Wallace, sufficiently illustrate
the point. These men were each botanist and zoologist in
almost equal degree and in the strictest sense. Their work
began out of doors with the vast riches of living plants
and animals, and the impetus from this source dominated all
they did.

In the highly subdivided and specialized biological realm
of to-day, those who are trained in either botany or zoology

75

'76 The Unity of the Organism

or in both, are perforce the ones who think most in terms
of the doctrine of evolution, and whose undertakings are
most guided and fashioned by evolutionary conceptions :
How and where and under what influences did these organ-
isms, these organs and tissues have their beginnings and
undergo development? So it happens that when a zoologist,
for example, is confronted with the vast array of chemical
compounds which his co-workers in the chemical laboratories
have made known, he is bound to extend to them his usual
string of queries. No matter how much information he is
given about the molecular construction, the solubility, the
reactions, the methods of laborator^^ production, of organic
compounds, he can be in no wise satisfied until he has been
told something about their original source, their way of get-
ting into existence, not only in the individual organisms but
also in the race. Many physiologists on the other hand, and
also it must be confessed, a considerable number of modern
botanists and zoologists, are very little concerned Avith such
questions. In fact it seems as though the evolution doctrine
had not made the slightest impression on many biologists
animated by the chemico-physiological spirit, so far as cjon-
cerns their attitude toward their special problems. These
students appear to "take" the substances they deal with as
things without beginnings, as eternally existent, or as com-
ing into being "by free grace," in some such way as pre-
Darwinian naturalists "took" their species. We had oc-
casion to refer at some length to a similar un-evolutionary
character of elementalist biology in a preceding chapter.

The question of how far such an attitude is due to the
fact that physics is preeminently not an evolutionary science
is one of great interest, both practical and theoretical. The
very basal conception of modern physics, that of Matter and
Energy as the only real things (as in the quotation from
Watson : ". . . in the pliysical universe there are only two
classes of things ; to these the names Matter and Energy are

The Organism and its Chemistry 77

given."), or at least as the most real of all things in nature,
seems to carry with it an element of liostility to evolution,
to the conception of origination by transformation and
growtli. But tliis is no place to deal with the vast problems
thus intimated; sufficient to have mentioned the matter for
the sake of a background for the discussion now before us.
Our standpoint in this chapter on the organism and its
chemical substances is to be that of the evolutionary natu-
ralist. We are to j)ush our studies of the structure and
function (the morphology and ])hysiology) of organisms
into chemical foundations, and are then to inquire concern-
ing the mode and place of origin of the foundational sub-
stances, and also concerning the adaptation of these to the
needs of the organism. In other words, we are to look upon
the chemical elements and compounds entering into the make
up of organisms in the same way that w'e look upon the cells,
tissues, and organs which enter into their composition. In
fidelity to the best traditions and practices of natural his-
tory for the last century at least, the evolutional and adap-
tational aspects of our inquiry will presuppose much careful
description, definition, comparison and classification of these
substances.

Touching the descriptions presupposed, the following
qualifying considerations should always be kept in mind :
The naturalist is entirely unable to "go behind the returns"
of the chemist in estimating the accuracy and fulness of the
descriptions. He must accept what is furnished him from
the chemical laboratories, exercising no critical judgment
beyond that always requisite in tlie choice of authorities
where one is obliged to go into fields not his own for facts.
From this consideration very little actual description of
organic chemical substances will be given in our discussion.
We shall in general restrict ourselves to substances the
existence and main attributes of which seem to be no longer
in question among chemists themselves.

78 The Unitij of the Organism

The second and more fundamental qualifying considera-
tion is that, knowing as he does something of the methods
by which the chemist gets at the chemical substances of or-
ganisms in order to describe them, the naturalist is unable
to suppose the compounds and processes described by his
chemical coworkers to be anything better than more or less
distant approaches to the substances that actually exist,
and the processes that actually go on in the organism as the
naturalist is primarily concerned with it ; that is, as living
normally. The naturalist accepts not only without hesita-
tion but with eagerness and gratitude the chemist's report
on what he is able to get out of the organism. That these
reports come near setting forth what the organism actually
is, the naturalist is bound to recognize cannot be the case.

This reservation the naturalist feels the more justified in
making by noticing that there are physiologists of unques-
tioned standing who hold views which amount really to the
same thing. Thus the distinction between living and dead
albumen (Eiweiss), first sharply drawn by Pfliiger (Ueber
die physiologische Verbrennung in den lebendigen Organis-
men, Archiv fiir die gesamten Physiologic, Bd. 10, 1875)
and since recognized by other investigators hardly less
eminent is manifestly of the same import. ( See, for example,
j\Iax Verworn, p. 596, Allegemeine Physiologic, sechstc Aufl.)

The Organism as a Chemical Laboratory

Immediately the fertilized Qg^r begins to develop, chemical
substances are produced within it. Among the higher ani-
mals the hen's ^gg has been the most studied in this as in
many other aspects. "Neither nucleo-proteins nor pentoses
are present in the fresh (^gg-, and purine bases are present
only in very small amounts. The fact that during develop-
ment these substances rapidly increase in amount indicates
therefore that a synthesis of nucleo-protein from the reserve

The Organism and its Chemistry 79

material of the egg (proteins and pliospliorized fats) takes
place during development." ^ This statement by Marshall
on the authority of Kossel and of Mendel and Leavenworth,
may be taken as typifying a wide range of present-day
knowledge of the synthesizing power of the growing embryo.
Because of its inaccessibility the mammalian ovum has
been but little studied chemically. However from what is
known of the chemistry of the eggs and embryos of other
animals, particularly' of the chick, we are entirely warranted
in asserting that a full grown man, for example, contains an
enormous number of chemical substances which are not pres-
ent in the egg from which he developed. The chondrin of
cartilage, the paraglobulin of blood serum, the haemoglobin
of red blood corpuscles, the nwosin of striated muscles, the
various enzymes of the digestive glands, the neurokeratin
and protagon of the central nei'^'ous system, and innumer-
able other compounds more or less specific for particular
organs and tissues, come into existence in the course of
development. And this production of new substances con-
tinues, with many organisms at least, up to the very end
of the developmental series, even to the end of the lives of
the organisms. This is well illustrated by the more or less
distinctive oils, essences, acids, etc. occurring in ripe fruit.
And few facts bring home more forcibly the subtlety and
intricacy of the organism as a producer of chemical sub-
stances than do odors and flavors of flowers and fruits.
The products of the organism's operations as a manufac-
turing chemist are seen to be of two rather shai'ply dis-
tinguishable sorts when the total chemical make-up of the
developed organism is compared with the total make-up (oi
the germ-cells. First there is a considerable number of sub-
stances common to adult and germ. Thus both tail and
head of the spermatozoa of various fishes were shown by
the well known researches of Miescher and Kossel to contain
lecithin and cholestrin, both substances occurring also in a

80 The Unity of the Organism

large number of adult tissues, as the blood, brain and nerves.
The nucleic acid of the spermatozoa is said by Cramer to be
very similar to that of the somatic cells and "probably iden-
tical with the nucleic acid prepared from the thymus." "
But more interesting- than the substances of identical struc-
ture which may be extracted from both germ and adult are
the series of mixtures of phosphorized fats more complex
than lecithin, which are present in the yolk of various eggs,
some portions of which disappear as development progresses,
seemingly being consumed as a part of the energy of develop-
ment.^ Other portions are transformed (?) substances of
the same general nature in the tissues.^

So far then as concerns substances that are identical in
germ-cells and cell^ of the mature organism, development
consists merely or primarily in increasing their quantity.
Such substances may consequently be looked upon as an
actual realization of the doctrine of preformation which
formerly played so great a role in speculative embryology.
But the number of substances remaining exactly the same
from the earliest to the latest stages of development is very
small in comparison ^vith the number wholly or partly new
in the later stages. So that from the chemical standpoint
development is for the most part strictly epigenetic; that
is, it is a process not merely of increasing the mass, the
quantity, of what previously existed, but as well of coming
into existence of new kinds of substance. It is a qualitative
as well as a quantitative, process. The living, growing or-
ganism is creative in the strictest sense and that on a vast
scale. "The lout," writes Oliver Wendell Holmes, "who lies
stretched on the tavern bench, with just mental activity
enough to keep his pipe from going out, is the unconscious
tenant of a laboratory where such combinations are con-
stantly being made as never Wohler or Berthelot could put
together : where such fabrics are woven, such colors dyed,
such a commerce carried on Avith the elements and forces

The Organism and its Chemistry 81

of the outer universe, that the industries of all the factories
and trading estahlishnients in the world are mere indolence
and awkwardness and unproductiveness compared with the
miraculous activities of which his lazy bulk is the unheeding
center." ^

The scientist cannot afford to let the literary quality of
this paragraph obscure the truth it expresses. The ac-
complishments of organic chemistry in producing substances
in the laboratory which it was formerly supposed could be
produced onl}' by the living organism, have been so brilliant
as to obscure somewhat the significance of the ibict that these
artificial products are imitations: Nature made them before
man did, and for the ends they originally answered they are
still produced only as they formerly were, by the organism
itself.

The fact that the chemist is able to produce what the
organism produces in no way derogates from the significance
of the fact that the organism does produce them. One can
hardly see the import of the point here made until he reflects
on the difference between the chemist's ability to produce
in his laboratory compounds which are the same as the dis-
carded end-products of the living organism's operations, or
wliich can be extracted from the dead body of the organism,
and the elaboration of substances which constitute the es-
sential parts of the organism while it is still living and work-
ing. The problem can be put in concrete form by noting
that the chemist produces certain substances in his labora-
tory by the activities of his brain and hands, and certain
other substances in his body by the activities of his digestive
organs, glands, muscles, brain and so on ; and then asking
how far those produced by the first means can be the same
as those produced by the second. May the operations of
the first kind be fully substituted for those of the second
kind? May the brain and the hands with the appropriate
laboratory apparatus ever be able to do the aictual ^york

82 The Unity of the Organism

of the liver for example, or the blood, or the testes or the
ovary? The views prevailing to-day among physiologists
and biochemists would favor an affirmative answer to these
questions. In order to maintain some show of modesty the
contention would be that while the chemist is not yet able
to make these substances, there is no reason for supposing
he will not be later. At any rate, so the view is, except for
practical manipulative difficulties the substitutions might
be made.

And it should be pointed out that thinking of the organ-
ism as a chemical laboratory, as suggested above, is not a
mere literary fancy somewhat tinctured with science. By
modifying the conception to the extent of making cells and
tissues instead of an individual man the laboratory, it has
figured considerably in recent biochemistry. According to
Bayliss,^ Hofmeister definitely formulated the idea in 1901,
so far as the cell is concerned, and it "is rapidly gaining
ground."

About the clearest statement of it I have come upon was-
made in 1913 by F. G. Hopkins. This biochemist illustrates
the synthesizing activities of the organism by several spe-
cific examples, the last of which concerns nicotinic acid.
When this "is fed to animals, it is excreted as trigonellin, a
known vegetable base. This conversion involves methyla-
tion, and is of striking character as an instance of the
artificially induced production of a plant alkaloid in the
animal body." ^ * At the conclusion of tlie illustrations
Hopkins says : "The known facts have, one feels, an aca-
demic character in the view of the physiologist and even in
that of the pharmacologist, to whom we owe most of our
knowledge about them. But, in my opinion, the chemical
response of the tissues to the chemical stimulus of foreign

* Looking upon the production here instanced as "artificially induced"
is worth noticing, since it clearly suggests that the conception of the
organism as "chemical lal)oratory" im})lies not only the laboratory luit
the chemist who works in it.

TJie Organism and its Chemistry 83

substances of simple constitution is of profound biological
significance. Apart from its biological bearings as the sim-
plest type of immunity reaction, it throws vivid light, and
its further study must throw fresh light, on the potentiali-
ties of the tissue laboratories." ^

Different Organisms as Different Chemical Laboratories

But this glance in the exclusively descriptive way, at the
chemical foundations of the organism in the various stages
of its life, in no wise satisfies the modern natural history
standpoint. As indicated in the remarks introductory to
this chapter, that standpoint is comparative as essentially
as it is descriptive. The moment this methodological plank
in the natural historian's platform is reached, the insuffi-
ciency is seen of the conclusion that some individual organ-
isms are manufacturing chemists or even that all are.
Taken thus the result is altogether too general. The most
cursory observation leads to the recognition that if every
organism be a producer of chemical substances, not all
organisms can be producers of the same substances, and
that the extent and nature of the diversity of products
w^ould be interesting and important from both scientific and
practical considerations. Now the comparative method in
zoology has its roots in the every day knowledge that ani-
mals and plants are to some extent different from one
another. Applying this method consistently and with suffi-
cient rigor for the present inquiry, the problem formulates
itself as follows : How far do the readily observable re-
semblances and differences betw^een organisms reach down
into their chemical make-up? Does the present state of
advancement of biochemistry warrant the supposition that
for every well-established similarity and for every well-es-
tablished difference between organisms, both as to individuals
and species and as to structure and function, there is a
corresponding chemical siinilarity and difference?

84 The Unity of the Organism

{a) Different Odors and Flavors of Animals and Plants as

Distinguish ahlc hy Man

The attcni])t to answer these questions should be prefaced
by calling attention to the fact that experience is very
familiar with a group of phenomena that bears directly on
the problem even though not much definite chemical knowl-
edge of these phenomena has yet been acquired. I refer to
the odors and flavors so wide-spread in the organic world.
Everybody knows that the odor of the cow is different from
that of the sheep, and that that of the pig is different from
both. Equally familiar is the fact that the flavor of the
meat of these three animals is different. Apples are dif-
ferent from pears in both smell and taste, as are peaches
from apricots. No one with normal senses of smell and
taste would ever mistake potatoes for turnips even thoug'.i
he did not touch or see them. We might go on indefinitely
mentioning differences of this sort in both the animal and
plant worlds. That these differences have a chemical basis
is certain. As is well known, the odors of living animals are
to a large extent dependent upon tlie secretions of various
glands of the skin, some of these being sweat-glands and
others glands of more specialized character. But the urine
and feces contribute much to animal odors, a large number
of more or less well known chemical substances being im-
plicated ; and the flavors of meat are known to be connected
to some extent with the bile.

These facts of common experience and of fragmentary
chemical experience lead naturally to more specific ques-
tions in two widely different directions. In the first place
we wish to know how far the odor differences, so sharply
characteristic of animal and plant groups widely separated
from one another in classification, hold as between groups
less and less separated; and second, we inquire whether the
phepiical differences which reveaj themselves by differences

The Oryanifim and its Chemistry 85

iii smell and taste, are the only or even the chief chemical
differences between tlie organisms concerned. Taking the
first question first, we may make it more specific by asking
if there is any evidence as to whether or not species of the
same genus and varieties of the same species are kn^own
to differ from one another in smell, or their flesh in taste.

Special students of mammals and birds seem to have given
less attention to odors as specific differences in these classes
than the subject deserves. I find little beyond incidental
reference to the matter in the literature consulted, and Dr.
Joseph Grinnell, Director of the Museum of Vertebrate
Zoology at the University of California, writes "I know of
no naturalist who has attempted to make a general classi-
ficatory stud}^ of odors." Answering my question as to
whether the different species of skunks and petrels are dis-
tinguishable by their odors, this experienced naturalist tells
me he cannot smell any difference between two species of
skunk, a Spilogale and a Mephitis^ and that the species of
the genus Oceanodroma (petrels) produce an odor which,
"as far as my experience has gone, seems identical in all
the species." But Dr. Grinnell says he can distinguish a
weasel from a skunk by smell, not only in the volume as one
might say, but in the quality of the odor. And the two
genera Mustila and Mephitis to which these animals belong,
are allowed by all mammologists to be rather close of kin.

As to petrels, Mr. L. M. Loomis, whose work on the water
birds of the Pacific Coast of North America is mdely and
favorably known, writes : "The strong musky odor of the
petrels renders their discovery in the rock piles easy. It is
only necessary to insert the nose into likely crevices to find
them. With little practice one may become very expert
in this kind of hunting, readily detennining whether it is an
auklet or a petrel that has its residence in any particular
cranny." The auklets and petrels are rather widely sep-
arated in the S3^stem of classification, being assigned to dif-

86 The Unity of the Organism

ferent orders. Nevertheless their similarity in food and
other habits makes this difference in odor interesting.

The great variety not onl}^ as to form and secretion but
as to position on the body, of the scent glands in the mam-
malia has an obvious bearing on the topic in hand. The
abdominal glands of the shrew-mice, the hip glands of the
mouse genus Microtus; the leg glands and foot glands and
suborbital glands of the deer family ; the anal glands of
many orders ; and the almost universal presence of glands
whose secretions are odoriferous connected with the sexual
organs, may be mentioned as illustrating the w^de distribu-
tion of such structures in the body. And it is noteworthy
that these may be present or absent in closely allied forms.
Thus the Indian rhinoceros {Rhinoceros indicus) is said
to have hoof glands while the Sumatran species (i?/i. Su-
matrensis) has none.^^

The well known fact may also be recalled that scent
glands are often distinctive of the sexes. The musk-deer
{Moschiis moschiferus) affords a particularly striking il-
lustration of this, not merely as to the production of the
perfume which makes this animal famous, but as to a glandu-
lar secretion of quite another sort. In the adult male there
is a naked area around the root of the tail which is, as
Darwin expresses it, "bedewed with an odoriferous fluid."
This area is neither devoid of hair nor secretory in the
female at any time in life, nor does it appear in the male
until he is two years old. Tliat the musk-gland of this
species is a strictly masculine affair goes without saying
when it is recalled that it is connected with the male sexual
organs.

Ants are particularly instructive from this as from many
other standpoints, the sense of smell in them being of far
greater importance relatively to the other senses than in
the higher orders. This has been established particularly
by the admirable researches of Forel and Wasmann. Cor-

The Organism and its Chemistry 87

responding to the high development of the olfactory sense
there is a great diversity of odoriferous substances produced
by these animals. Something of the extent of this diver-
sification is indicated by Wheeler, the foremost student of
ants in this country, who remarks: "Even the degenerate
human olfactories can detect the different species and in
some cases even the different castes of ants (Eciton) by their
odors." ^^

Among plants there are many examples of easily recog-
nizable differences in smell and taste between species of the
same genus and even between varieties of the same species.
In some species of Rhus, for example R. integrifolia, the
ripe fruit is covered with a thick, white, pasty exudate
which is extremely sour, while the fruit of R. laurina has
no trace of such a product. Since these species are both
native of southern California and often occur together, they
furnish an impressive instance of difference in chemical ac-
tivity of two closely related plants. While referring to
RhuSy the familiar fact that some of the species as Rhus
lobata "Poison-oak" produce an exceedingly active poison
while others do not, may be noted as a case of undoubted
chemical difference between species that are close of kin.
And this difference in the poison producing habit of plants
is rather common and found in widely separated portions of
the plant world. The cases of Rhus and Solanum, some
species of which are poisonous and some are not, chosen
from the higher plants, are paralleled by the genus Amanita
(mushrooms) among lower plants. According to Charles
Mcllvaine, of the twenty-seven species of the genus, nine are
edible, nine are known to be either deadly or are so closely
allied to deadly species that it is unsafe to class them as
other than poisonous ; while about the others nothing is
known in this regard.

Some tests on apples make it highly probable that the
different kinds might be distinguished from one another to

88 The Unity of the Organism

a high degree of nicety, by smelling them. This is the case
with three varieties selected by chance and known locally as
"wine-saps," "pippins," and "pearmains." In attempts to
recognize them blindfolded the successes were considerably
more numerous than the failures. This conjecture is clearly
supported by the familiar fact that some groups of varie-
ties, as for example the russets, are less odoriferous than
other gr'oups ; and that other varieties as the "belle fleur"
have a higlily characteristic odor.

The suggestion that not only apples and fruits and flow-
ers are distinguishable by their odors to a far greater ex-
tent than we are accustomed to suppose, is in keeping with
the well known trade practices of tea-tasting, wine-tasting,
tobacco snifling and so on.

(h) Differences in Animal Odors as Distinguished hy Animals

Themselves

Even though the little eff*ort that has been made by na-
turaKsts to distinguish species and varieties of animals and
plants by smell does not warrant the assertion that differ-
ences of this degree of refinement do not exist, it yet would
not be worth w^hile to speculate on the possibility of their
existence had we not evidence of their existence of quite a
diff*erent sort from that furnished by the naturalist's nose.
I refer to the evidence furnished by the noses of the animals
themselves ; evidence, in a word, of the extent to which ani-
mals recognize one another by smell. Although we have
only a few thoroughgoing researches in which animals have
been made to serve through their sense of smell as analytical
chemists of one another, the few we have are exceedingly
interesting. The case of ants which has received so much at-
tention in recent years may be brought forward first in
illustration of the point. "The multiplicity of lodors," says
Fore], "is enormous, and it is possible to demonstrate, as I

The Organism and its Chemistry 89

have done for the ants, and von Buttel-Reepen for the bees,
that these animals in distinguishing their different nest-
mates and their enemies, betray nothing beyond the percep-
tion of extremely delicate and numerous gradations in the
qualities of odors." ^^ And continuing the statement quoted
from above relative to the odors of ants recognizable by
man, Wheeler says, "but these insects carry the discrimina-
tion much further. They not only differentiate the different
odors peculiar to species, sex, caste, and individual, and tlie
adventitious or 'incurred' odors of the nest and environ-
ment, but, according to Miss Fielde, tliey can detect 'pro-
gressive odors' due to change of physiological condition
with the age of the individual." ^^

Miss Fielde's formulation of her hypothesis referred to
by Wheeler is as follows: "1. The Specific Odor — The moth-
er-ant transmits to her offspring the distinctive odor which
is identical for ants of all ages and of both sexes within
the species. 2. Progressive Odor. — Female ants, including
queens and workers, have, beside their specific odor, an odor
which m^y be termed progressive. Queens of different lin-
eage have different progressive odors. In a queen this odor
is either unchanging or changes very slowly, and it is sim-
ilar to that of her newly hatched offspring. As worker-
ants advance in age their progressive odor intensifies or
changes to such a degree that they may be said to attain
a new odor every two or three months." ^'*

To Ernest Seton is due credit for the nearest approach
tliat has been made to a scientific application of this metliod
of discovering chemical differences between animals of the
vertebrate orders. The theory of what he calls scent-
language is founded on his study of carnivorous animals
which hunt by smell.

Nor can we, while on this subiect of odors as a means by
which individual animals of the same group distinguish one
another, neglect the case of the human animal.

90 The Unity of the Organism

The well known fact that some at least of the races of
mankind emit distinctive odors may be first alluded to.

"The Lord He loves the nigger well,
He knows His nigger by the smell,"

is the way the negroes of the West Indies are said to express
their claim to distinction through this character. Anthro-
pologists generally recognize that races are differentiated to
some extent in this way. Thus Deniker,'' while not certain
that the claims made by such travelers as Erman and Hue,
can be fully allowed that populations may be recognized by
their odors, still affirms the constanc}^ of difference between
some races in this regard. He accepts the statement that
peculiarities in the smell of negroes and Chinese cannot be
fully obliterated even "with most scrupulous cleanliness."
Nor has this author neglected to note the importance of
distinguishing between odors that are "sui generis" as he
says, and those due to odoriferous foods or other substances
with which certain peoples are habitually associated.

Ludwig Hopf asserts, largely on the authority of Jager,
that "some people have the power of differentiating rela-
tively insignificant odours of individuals as well as family
odours, and even the peculiar scent attaching to th^ inhabi-
tants of the same village (spezifische dorferriiche)." ^^

The Naturalist's Approach to Biochemical Problems

We now pass to the examination of the chemical nature
of organisms as this has been determined by chemical re-
searches proper. The first remark to be made under this
head must be on the exceedingly detached and haphazard
character of the knowledge in this realm when it is looked
upon from the standpoint of the zoologist and the botanist.
I hasten to explain my meaning of "detached and haphaz-
ard" and of being "looked upon from the standpoint of the

The Orgnnifim and its Chemistry 91

zoologist and botanist" for the statement may sound dep-
recatory of biochemistry and its allied branches.

As to actual quantity of knowledge and also as to the
complexity and reconditeness and exactness of much of that
knowledge, the chemistry of organisms is an impressive and
admiration-compelling science indeed. When, however, the
naturalist plunges into the great archives and monographs
and handbooks in which the knowledge is stored, that he
may find what there is that will contribute to the deepening
and broadening of his systematic information about and in-
terpretation of the animal and plant worlds, he soon becomes
aware that this knowledge has not been gathered with any
reference to the initial and most elementah needs of liis en-
terprise; that is, with reference to the necessities of describ-
ing and classifying the natural objects, the animals and
plants -wdth which he deals. What he finds is that the in-
vestigators who have produced the knowledge have been
in the main impelled by their interest in certain junctions
as displayed by the most familiar animals and plants, man's
own organ-activities being by far the most usual starting
point. For example, some young physiologist, ambitious
and energetic, becomes interested in a particular function,
say the circulation of the blood or muscular contraction or
digestion, wins a reputation by his studies, and being, as
most investigators have ever been, a teacher in some institu-
tion of learning, draws assistants and students into the re-
searches, and much new knowledge, with perhaps a whole
system of theoretical views, is developed concerning this
particular activity. And what has been the material on
which the researches have been prosecuted .^ If blood and
its physiological role stands at the center of his interest,
blood first and foremost, is what he wants and must have
for his studies. What animal within wide limits it comes
from matters little. The very fact that a fluid is found
in many animals so alike as to receive a single name, bloody

92 The Unity of the Organism

accepted without question as applicable in all the cases, is
a guarantee that it has more in common in all the cases
than the attributes by which it is familiarly recognized. For
instance the redness of the fluid in all vertebrates makes it
almost certain that with the obviously common color there
will be other coinmon attributes not obvious to ordinary ob-
serv^ation. And so it happens that our physiologist goes
to the dog or the ox or the horse or the rabbit, or with a
little more hesitancy, to the frog for his supply, these being
as a rule the most convenient sources.

One cannot reflect too carefully on tlie diff'erence between
this mode of approach to the phenomena of organisms, and
that peculiar to the natural historian. Consider a moment
the difference as touching one thing, the blood, and as be-
tween only two animals, the dog and ox let us say. Notice
first that whereas the physiologist's primary interest would
be satisfied with what he might get from a study of tlie blood
of either of these animals without reference to the other,
not so with the naturalist. Just blood is what the physiolo-
gist is concerned witli in this particular series of researches.
Comparison is no essential part of his enterprise. All he
does in this way is incidental, is secondary. Could he get all
the dog's bliood he needed to make out all that can be learned
about that blood, he would never concern himself as a strict
physiologist about the blood of any otlier animal. The
physiologist so far as he holds himself to his calHng, and
accepts his calHng as it has delimited itself in modern times,
namely, as having for its field one aspect of organisms,
i.e., their functions, can never consistently go outside of
function except incidentally — except for such morphological
facts as are essentially related in one way or another to
function. To the physiologist blood is blood no matter
whether from a dog or an ox.

To tlie zoologist, on the other liand, blood is never just
blood. It is always blood of a dog or of an ox, or of some

The Organism and its Chemistry 93

other animal, for the animal as an animal, the dog as a
dog, the ox as an ox, is an avowed concern of his. So it
comes about, as said in a former section, that the compara-
tive method is fundamental to tlic naturalist. From this it
directlv follows that for him differences between organisms
are no less basal than are similarities. As a zoologist in the
strict sense he is no more concerned with the problem of
wherein the bloods of the doo; and the ox are alike than in
that of wherein they are unlike. This is so because the dog
and the ox being both animals, neither can be to him of any
more significance or interest than the other, so that which
makes the dog a dog is no more and no less significant than
that which makes the ox an ox, and it matters not at all
whether the differentiating attributes pertain to the feet
or teeth or ears or stomach or blood. See then what this
implies as regards the zoologist's attitude toward the chem-
ical makeup of the dog and the ox. He wants to know
everything about the chemistry of the dog, and also of the
ox. It implies that the taxonomizing naturalist must be
chemical-minded to some extent and also that the biochemist
must be a taxonomic naturalist to some extent.

That the comparative method, so fundamental and indis-
pensable to the naturalist, becomes no less so to the bio-
chemist before his work is done, finds no better illustration
than in this very problem of the chemistry of the blood.
The effects of the bloods of different species of animals upon
one another has now become a recognized and important
branch of biochemistry. But here is a point the significance
of which neither biologists nor chemists appear to have fully
grasped : the discoveries in this field could not have been
made by any other means than those by which they were
made, that is, by actually mingling the bloods of different
animals in the living animals. Chemical discoveries of great
importance are here dependent absolutely on one of the
naturalisfs most cherished methods, the comparative, the

94 The Unity of the Organism

chemist having, however, sui'passed the iiaturaHst in the
refinement of the method. This coming of the chemist into
the field of the taxonomist is of the utmost interest to the
naturalist, since on the naturalist's principle of "neglect
nothing" it is impossible for him to be satisfied until he
knows the chemical as well as the anatomical and histolo-
gical makeup of organisms.

Not organic-chemistry nor physiologic- nor bio-chemistry
is what he wants, but homonine, bovine, canine, salmonine,
quercine chemistry, and so on. Surely nothing less than
this will satisfy him and probably this will not, for even it
is only generic chemistry; it is not species chemistry, much
less individual chemistry, and in all probability the time
is not far distant when he will demand individual or per-
sonal chemistry.

From the standpoint of chemical practice this demand is
almost overwhelming. Take a live dog or even a live shark
to the best manned and best equipped chemical laboratory
on earth and seriously propose that a complete chemical
analysis be made, and what sort of an answer do you sup-
pose you would get? Still more what will the answer be
when you go on to say to the director of the laboratory that
the analysis of this dog alone will not meet your needs, but
that one other animal at least must be analyzed with equal
care and completeness since your enterprise is as essentially
comparative as it is descriptive and that really what you
will finally call for will be an equally thorough analysis of
every animal.

These reflections lead straight-away to the inquiry, first
in a general way, as to how much may be found in the store-
houses of chemical knowledge that is to the naturalist's
pui'pose; and second, as to whether or not chemical re-
searches of the sort needed by him have been undertaken
to any extent. Or turning this into language in which the
naturalist is wont to express himself, how far has biocheii]-

The Organism and its Chemistry 95

istry become systematic biochemistry? How far has it. un-
dertaken to contribute to the vast task of describing and
classifying and interpreting tlie world of limng beings? Or
varying the form of the question a little, how far has biotic
chemistry become biologic chemistry? How far has the
chemistry of organisms become biologically scientific in the
systematic sense?

Some Biochemical Results Viewed from the Naturalist^s

Standpoint

With a stronger desire to indicate a naturalist's apprecia-
tion than to observe historical or logical sequences in treat-
ment, I speak first of the most important research which
up to that time had been made in this direction. Reference
is made to the monumental undertaking conceived and now
well advanced by E. T. Reichert. The title to the install-
ment so far published deserves special notice : "The Differ-
entiation and Specificity of Corresponding Proteins and
other Vital Substances in relation to Biological Classifica-
tion and Organic Evolution ; The Crystallography of Hemo-
globins."

Highly significant from the standpoint of method no less
than from that of accomplishment is the fact that in order
to carry through this piece of work, Reichert was obliged
to associate himself with a mineralogist, and that in his
university colleague, A. P. Browm, he found a man both
capable and willing to undertake the task.

(a) Reichert and Browns Results on Haemoglobin

The discussion will be best served by seeing first the main
factual results of the research. Afterward Reichert's mode
of approach and interpretation of these results can be con-
sidered. Reichert has summed up in a short paragraph of

96 The Unity of the Organism

the preface written by himself alone what was made out by
the observations : "It has been conclusively shown not only
that corresponding hemoglobins are not identical, but also
that their peculiarities are of positive generic specificity,
and even much more sensitive in their differentiations than
the 'zooprecipitin test.' Moreover it has been found that
one can with some certainty predict by these peculiarities,
without previous knowledge of the species from which the
hemoglobins were derived, whether or not interbreeding is
probable or possible, and also certain characteristics of
habit, etc., as will be seen in the context. The question of
inter-breeding has, for instance, seemed perfectly clear in
the case of Canidae and Mnridae, and no difficulty was ex-
perienced in forecasting similarities and dissimilarities of
habit in Sciurldoe, Murldae, Felidae, etc., not because hemo-
globin is per se the determining factor, but because, accord-
ing to this hypothesis it sei"\'es as an index (gross though
it be, witli our present knowledge) of those physico-chemical
properties which serve directly or indirectly to differ-
entiate genera, species, and individuals." ^^ This investiga-
tion was extended to the blood of more than one hundred
species of vertebrates and included representatives of all
the classes of the phylum, though many more mammals
than any of the other classes were studied. In several gen-
era, as Canis and Felis, a number of species and varieties
were included.

The crystallographic method was used almost exclusively
in the investigation. Concerning the value of this method
for recognizing cliemical similarities and differences, the au-
thors, trusting partly to such authorities as Groth, rest on
the view that "Differences of chemical constitution are ac-
companied by differences of pliysical structure, and tlie
crystallographic test of the differences of chemical consti-
tution is recognized as the most delicate test of such dif-
ferences." ^^ In accordance with this the dictum, "Sub-

The Organism and its Chemistry 97

stances that show differences in crystallographic structure
are different chemical substances" ^^ is accepted.

As far as the conditions of the researches would permit,
the crystals of oxyhemoglobin were made the standard of
comparison. When several forms of this are obtained from
the same blood "eacli form, A-oxyhemoglobin, B-oxyhemo-
globin, etc., appears always in its own proper form and
axial ratio when the blood of different individuals of the
same species are examined. The same is true of the
other hemoglobins — metoxyhemoglobin, reduced hemoglobin,
methemoglobin ; so that the hemoglobins of any species are
definite substances for that species. But upon comparing
the corresponding substances in different species of a genus
it is generally found that they differ the one from the other
to a greater or less degree ; the differences being such that
when complete crystallographic data are available, the dif-
ferent species can be distinguished by these differences in
their hemoglobins. As these hemoglobins crystallize in iso-
morphous series, the differences between the angles of the
crystals of the species of a genus are not, as a rule, great;
but they are as great as is usually found to be the case
with minerals or chemical salts that belong to an isomor-
phous group." ^^ In illustration we may select the table
for the species of cats studied, this being based on the crys-
tals of reduced hemoglohi/n. Tlie crystals belong to the
orthorhombic system and are optically positive for all the
species, so these items need not appear in the table.

Angle of unit

Angle of

ISame of Species

Axial ratio

prisms (normals)

macro donne
normals

Felis leo

0.9743:1:0.3707

88 30'

41 50'

F. tiajris

0.9742:1:0.3838

88 30'

43 0'

F. bengalensis

0.9657:1:0.3667

88 0'

41 35'

F. pardalis

0.9489:1:0.3931

87 0'

45 0'

X

F. domestica

0.9(5.56:1:0.3839

88 0' ■

43 20'

I^ynx rufus

0.9869:1:0.3914

89 15'

42 46'

L. canadensis

0.9605:1:0.3944

87 42'

41 30'

98 The Unity of the Organism

As another example the table for the crystals of B-oxy-

heiiioglobin from the baboons of the genus Papio is chosen.

These all belong to the monoclinic system and all except

those from the Guinea Baboon (P. sphinx) are optically

positive.

Prism,
Name of species Axial ratio Angle B angle

Yellow Baboon {Papio babuin) 1.6808:1 :c' 72° 72' 30" 118 30'

Guinea Baboon (P. sphinx) 1.8418 :l:c' 70° 123 0'

Long-armed Baboon (P. Langheldi) 1.655 :l:c' 70° 30' 117 44'

Chacma (P. porcarius) 1.732 :l:c' 75° 120 0'

Anubis (P. anubis) 1.737 :l:c' 72° 30' 120° 11'

So far as one with little knowledge of crystallography
may judge the numerous tables of which these two are sam-
ples, the copious illustrations many of which are from pho-
tographs, and the discussions, seem to justify fully the
generalizations above quoted, with others to which no ref-
erence has been made. It would however be quite wrong to
gain the impression that the very positive conclusions as to
the specificity of hemoglobin crystals reached by these
authors is in accord with all researches that have been made
on the subject. Summing up their rather extensive re-
view of studies previous to theirs, the authors say : "Equally
expert observers working with blood of the same species
have arrived at very different conclusions as to the specific-
ity or non-specificity of hemoglobin crystals in relation to
species, some claiming that the crystals are occasionally
specific, others that they are always specific, and others that
they are not specific because the same blood may yield crys-
tals of very different forms and that the differences are
probably accidental. Crystals of various colors and vary-
ing forms have been obtained from the same blood." ^^

A highly significant thing that comes from considering
the results reached by those students who have opposed the
idea of specificity of hemoglobin from different kinds of
animals, is not that they claim that all hemoglobin crystals

The Organism and its Chemistry 99

are alike, or even that only a few sorts can be demonstrated,
but that the great number of kinds do not correspond in
any definite way to different kinds of animals. And here
comes the particular point made against these views by
Heichert and Brown — and it is of great importance gener-
ally, and peculiarly interesting to the natural historian.
They show that the reason wlu' so many previous observers
have failed to find a correspondence between kinds of crys-
tals and kinds of animals, is that the crystals have not been
described zmth sufficie7it fulness and accuracy. In a word
the issue is, to the naturalist, the old and familiar one of
descrijjtion, comparison and classification. For example,
the authors lay particular stress upon the insufficient atten-
tion hitherto given to the crystal fomis of the different
sub-species of hemoglobins, namely, oxyhemoglobin, re-
duced hemoglobin, metoxyhemoglobin, methemoglobin, etc.
Again they point out the great inadequacy of earlier studies
in the determinations of the axial relations and other phys-
ical attributes of the crystals. The upshot of their cnti-
cism of previous studies as seen in the light of their own,
is that when a classification of hemoglobin crystals from
the blood of many kinds of animals is based on sufficiently
thorough going description, that classification correlates
itself with the kinds of animals from which the blood is
taken.

(6) The Precipitin Reaction Between Bloods of Different

Animals

If our comparative chemical knowledge of vertebrate
blood were limited to the results of studies like this by
Reichert and Brown, the presumption in the absence of very
positive evidence to the contrary, would yet be strongly
in favor of the hypothesis that the blood of each animal
species is in some of its constituents unique to that species.

100 The Unity of the Organism

As is now widely known, this hypothesis is supported by
another great mass of evidence from quite a different source,
whicli though not as directly cliemical as that just adduced,
is still so clearly so in its implications that reference to it
in this chapter is undoubtedly justifiable. What is in mind
arc the discoveries of recent years touching the compatibility
and non-compatibility of the blood of one kind of animal
for that of another kind ; discoveries in other words, con-
cerning the so-called "precipitin reaction" as between or-
ganisms of different kinds. Although this subject has at-
tracted a good measure of attention, only a portion of its
more fundamental significations has been much regarded.
Its bearings on problems of affinity and racial descent, for
example, have elicited their due of interest. But its con-
tribution to light upon the o]:)posite aspect of animal nature,
namely, that of difference as well as of likeness between
kinds, has not been appreciated in proportion to its merits.
Once grasp the conception of each organic species, to say
nothing of each indi\adual, as something genuinely unique
in the world in certain of its more obvious attributes, as a
scheme of organization, shape, etc., and then extend this
down into basal composition and process, so that the organ-
ism is seen in its role not merely of transformer and creator,
but to some extent of exclusive transformer and creator of
the elements of which it is constructed, and these and kin-
dred discoveries fall into their right perspective of meaning
and interest.

The underlying general principle of the precipitin reac-
tion i^ that of the production within the organism of anti-
hodies as a result of injecting into it certain foreign sub-
stances which, when the reaction occurs, are known as anti-
ge7is, the anti-gerhs and anti-bodies usually reacting definitely
and specifically upon each other. In one form of this re-
action the antibody acting upon certain proteins, forms a
precipitate, this precipitate carrying down both the antigen

The Organhm and its Chemhirif 101

and the antibody. The point of special significance for us
now is tliat the blood of a given species of animal has been
found to act as an antigen when injected into the circula-
tion of another species, and the extent of the reaction is in
large measure dependent on the degree of affinity between
the animal species to which the different bloods pertain.

A particularly instructive case worked out by Hamburger
is given by Arrhenius. Serum from a rabbit was treated
with serum from a sheep, the rabbit serum being in this way
made to contain an antibody. The rabbit serum tlms af-
fected was then used for experimenting upon the serum of
a normal sheep, a goat and an ox, with a view to testing
(juantitatively the action in the three cases. The same
quantity of rabbit serum containing the antibody was used
in each case, as was also the same quantity of equally diluted
serum of the animals to be tested, and the amount of pre-
cipitate in each case was measured. The results given in
terms of the antibody or precipitin, rather than in that of
the precipitate are, in Arrhenius' words, as follows: "On
injection of sheep-serum into rabbit blood we have obtained
an antiserum containing per centimeter cube 300 equivalents
of ])recipitin against sheep-serum, 212 equivalents of preci-
pitin against goat-serum, and only 90 equivalents of pre-
cipitin against bullock-serum." ^^ This result is obviously
in agreement with the general zoological evidence that the
goat and the sheep are somewhat closer of kin than the
ox and the sheep or the ox and the goat.

Another inference of quite different import drawn from
the experiments is not to be missed, namely, that the dif-
ferent amounts of precipitation in the three sera is not due
merely to a quantitative difference in the precipitin con-
tained in the rabbit serum, but that there are really three
precipitins involved. This conclusion, Arrhenius points out,
se^ms necessitated by the fact that a unit quantity (1 c. c.)
of the normal serum from each of the three animals tested

102 The Unity of the Organism

contains nearly the same number of equivalents of the
precipitate.

In his well known work Blood Immunity and Blood Re-
lationship, G. Nuttall has applied this principle more widely
to the animal kingdom than any one else.

(c) Comparative Chemistry of the Sperm of Different

Species of Fislies

Several biologists are impressed with the importance of
knowledge in tiiis field as bearing on philosophical natural
history. No physiologist has so far as I am aware, ventured
quite so far into the realm of prophecy with reference to it
as has E. Abderhalden. He points out the possibility of
increasing the number of attributes now recognized as dis-
tinguishing not only species but individuals through a sys-
tematic and concerted carrying out of researches already
begun in this field, and foresees the time when biochemistry
will play a leading role in problems of racial descent and
taxonomic affinity.-^ The march of research in the decade
since Abderhalden made these forecasts, has undoubtedly
been toward a fulfillment of them, at least as touching bio-
chemical distinctions between individuals. Thus C. Todd
has very recently given a useful summary of what has been
done up to the present hour on the comparative chemistry
of the blood as revealed by the methods here being consid-
ered, and an account of an exceedingly interesting resarch
of his own.

The chemico-zoological researches standing next in in-
terest and importance to those on the blood are the well
known ones inaugurated by ^liescher and continued by Kos-
sel and liis students, on the spermatozoa of fish. Miescher
discovered in the sperm of the salmon a group of protein
substances called by him protamines, which are said not
to have been found as yet elsewhere than in fish sperm.

The Orgavism and itfi Chemistr?/ 103

There has been some question whether these are true
proteids, but at any rate they seem to be relatively simple
and definite in composition so that Kossel has regarded
them as the foundation of the protein bodies. It has been
possible to^work out probable empirical formulae for them,
and herein their natural history significance comes strikingly
to view. The formula C32H54N18O4 was assigned by Miescher
to the protamine of Salmon sperm, the substance being
proved to contain the nucleic acid radical. The comparative
studies of Kossel and his students extended to the sperm
of the herring, mackerel, sturgeon, and perch, and brought
out the fact that while the nucleic acid part of the molecule
is the same for the different genera, the basic part is dif-
ferent in each, so a name is required for the protamine de-
rived from each kind of fish. The names salmme, clupeme,
scombrine, sturine, cyprinine, cyclopterine, etc., proposed
by Kossel have consequently come into general use. These
differ in formulae. Thus Kossel gives clupine as C30H62N14
O9 and sturine as CseHegNigOy. They also differ in the
cleavage products yielded, histidine for example, being ex-
tracted from sturine and from none of the others, and tyr-
rosine from cyclopterine exclusively. All, on the other
hand, yield arginine while lycine was found only in sturine
and cyprinine, and so on.

(r/) Comparative Chemistry of Milk From Different Species

The milk of several species of mammals has been ex-
tensively investigated mostly from physiological and dietetic
standpoints, but the difference between the milks of dif-
ferent groups has come out with positiveness. It seems that
on the whole the milks of carnivorous species are more alike,
and those of herbivorous species are more alike, than those
of either of these categories are like those of the other, but
there are not enough observations to warrant laying this

104 The Unity of the Organism

down as a law. As thorough a chemico-zoological investi-
gation of milk as that made by Reichert and Brown of
blood, ought to yield highly interesting results, for not only
common knowledge, but technical knowledge as well, obtained
in connection with the dairy industry recognizes that even
as between different breeds of cows the milk differs in con-
stitution. Jersey cows for example, produce milk contain-
ing a larger proportion of butter fat than do Ayrshires, and
some at least of these breed-differences in milk cannot be
explained on the basis of differences in food or other en-
vironmental factors, powerfully as these do undoubtedly
influence milk.

Attention may be called to the extreme chemical sensitive-
ness of this fluid as a registering instrument. "Circum-
stances tending to cause discomfort usually lower the pro-
portion of volatile acids present in the butter-fat, but the
variation in the composition is very irregular, and appears
to depend partly upon the nervous temperament of the
cow." ^^ And there is ample evidence that the character of
the milk of women may be so changed by nervous and mental
conditions as to become unfit for the nursing babe.^^

{e) Comparative Chemistry of Digestive Enzymes

Another great field of chemico-zoological research has
recently been opened up by studies on the enzymes of diges-
tion. The investigations of this sort which we will notice
have been specially prosecuted by the Swedish chemist, S.
Hedin. The results are given in outline by A. Hardens
and from this the following statement is, in the main,
drawn. ^^ The problem concerns rennet, the familiar milk
clotting substance produced in the calf's stomacli, and
Hedin's results are not influenced so far as I can see, by
the much debated question of whether or not pepsin and
rennin are two entirely distinct bodies. It is shown that the

The Organism and its Chemistry 105

mother-substance, the zymogen, of the clot-inducing sub-
stance is not simple but is a compound of the enzyme and an
inhibitant for that enzyme. By proper treatment of the
water extract of rennet with dilute acid, the enzyme is
liberated and the inhibitant destroyed, while if the treat-
ment be with dilute alkali the enzyme is destroyed and the
inhibitant liberated. But if the solutions containing the
two opposing substances are mixed, recombination takes
place and the resulting solution has the attribute of the
original water solution of rennet, namely, that of clot-pro-
duction to a sliglit degree only.

To be specially noted is tlie fact that the inhibitant of a
given rennet neutralized the enzyme of that same rennet.
Now comes the thing of special importance from the stand-
point of comparative zoology : When solutions of both en-
zymes and inhibitants are prepared from different species
of animals (the calf, the jjig, the guinea pig, and the pika,
were used in the experiments), it turns out that tlie in-
hibitant from the rennet of one species does not inhibit the
enzyme from the rennet of another species. And so it is
concluded that ''both the enzyme and the inhibitant are dif-
ferent for each animal, a fact of great interest and impor-
tance," to repeat Harden's words.

Special attention should be called to the circumstance that
not only is this another method of differentiating species
chemically, but that it is an exceedingly delicate me'thod.
This is particularly seen in the fact that the rennets of the
species investigated were found capable of clotting cow's
milk in spite of their being different in other respects as
just shown, it being thus revealed that the fact that rennets
from two different animals may act alike on cow's milk,
does not prove them to be alike in all their attributes. No
careful student of nature will ever neglect the principle
involved in this. We may take this as an impressive re-
minder that the problems of the dependence and the inde-

106 The Unity of the Organism

pendence of characters, so much to the front now in con-
nection with the Mendelian mode of biological inheritance,
extends down into the chemical reactions taking place within
the organism.

(f) Instances in General Biochemistry Where Interesting
Facts of Comparative Chemistry are Incidentally

Brought Out

If now, taking our cue from these several distinct groups
of positive evidence of a close correlation between attributes
by which the naturalist ordinarily distinguishes individuals,
varieties, species, genera, etc., and chemical attributes of
these groups, we look through biochemical works which have
no natural history intent so far as their authors are con-
cerned, with the end in view of seeing to what extent they
nevertheless contain incidental facts and statements which
are in keeping with the results of the chemico-zoological re-
searches just considered, we find an almost unlimited number
of records of such import. We will notice a few of these,
selecting them mainly with reference to the very wide range,
both chemical and biological, from which they may be drawn.

One of these works has lately produced good experimental
reasons for believing that trypsin of the liver of "the star
fish" is considerably different from that derived from the
same organ of the "large soft-shelled California Clam." So
far as concerns the research here referred to, what species
of starfish was used probably did not matter much, but to
the zoologist bent on pushing as far as possible his knowl-
edge of the differences between animals, the point is of
genuine interest since the fragment of information thrown
out might serve as the starting place for an important
cliemico-zoological study of the organs rather indiscrimin-
ately called liver occurring in many invertebrates. But
even this additional knowledge, for we have much besides,
favorable to tlie conception that trypsin can never be looked

The Orgnmsm and its Chemisfr?/ 107

upon as just trypsin, but must be regarded as the trypsin
of some particular species, or possibly variety, or even
individual.

A. P. Mathews, more regardful of the source of his scien-
tific blessings, that is, of the material on which he works,
as well as of other essentials, is explicit and informs us that
the eggs of the sea-urchin Arbacea punctulata, differ
markedly in their physiological properties from those of
the stai*fish Asterias forbesii. The differences in "physi-
ological properties" noticed consist in the greater stability
of the sea-urchin egg as manifest in its resistance to oxida-
tion, low rate of respiration, and relative insensibility to
stimuli inducing artificial parthenogenesis. These differences
Mathews finds to be correlated with the possession by the
sea-urchin egg of considerable quantities of the widespread
substance cholesterol, and the absence either wholly or in
part, of that substance in the starfish egg.

The Coalescence of Natural History and Comj)cirative

Chemistry*

It seems then from all this that natural history and bio-
chemistry are being inevitably drawn together by the very

* Since this chapter was written J. Loeb's The Orc/anism as a Whole
has been published. It is gratifying to find in this book evidence that
the author is being carried, as it seems to me, unconsciouslj'^ perhaps,
toward the organismal and natural history standpoint. One piece of
such evidence may Ije appropriately noticed at this point. It is that
I.oeb gives us a chapter with the title The Chemical Basis of Geims and
Species. This seems to show that now, since specificity is coming down
to a chemical basis, taxonomy is assuming a reality and significance in
this author's mind which it did not have formerly. But attention should
be called to the fact that knowledge of the chemical differentiation of
taxonomic categories has not made their reality one whit more posi-
tive than it was before. The chemist is following the naturalist and
refininy the latter's methods in certain particulars beyond anything he
himself is capable of. "In certain particulars," I say, because in certain
other particulars the naturalist is still far in advance of the chemist.
Thus the naturalist knows beyond a trace of uncertainty innumerable
"specific differences" among plants and animals which the chemist, as
a chemist, can not yet so much as touch. In fact, the lack of compre-

108 The Unity of the Organism

nature of the subject matter with which they are occupied.
Descriptive zoology and botany are to become chemical in
part, and the chemistry of organisms is to become zoological
and botanical in part. Each science is to supplement,
and reciprocally to be supplemented by the other far more
essentially than has hitherto been the case. In one of its
aspects biochemistry will become a branch of systematic
zoology and botany, just as biology in one of its depart-
ments, is already a branch of chemistry. Although such a
state of things is very far from full realization, that the
movement is in tliis direction seems unmistakable. Tlie con-
ception that animals and plants as producers of chemical
substances, and that each kind if not each individual is to
some extent a producer of different substances is receiving
new confirmation all the time.

When we pass from the primary task of identifying and
describing the chemical substances produced by different
animals and plants to that of gaining an insight into the
methods by wliicli these substances are produced; when, in
otlier words, we pass from the problems of What to those
of How, the vast complexity and uniqueness not only of the
chemical operations of organisms as distinguished from
non-organisms, but as well the uniqueness, within limits, of
these operations come even more impressively into view. A

hensiveness and of refinement in some directions of the chemist's descrip-
tions receives striking iUustration in this very book "The Organism
as a Whole." Restricting his consideration of the chemical bases of
species to the evidence drawn from laboratory experimentation, Loeb
writes: "Ford claims to have obtained proof that a glucoside contained
in the poisonous mushroom Amanita i)h(tJJokles can act as an antigen.
But aside from this one fact we know that proteins and only proteins
can act as antigens and are therefore the bearers of the specificity of
living organisms." (p. (i.'i). Exactly what is meant by "bearers of the
specificity of organisms" no one knows, but if the assertion implies, as
it seems to, that all such dift'erences are due exclusively to proteins, it
is contrary to a vast array of indubitable facts of natural history. Dif-
ferential otlors and flavors, for example, as dwelt upon above, are
certainly not all, probably not usually, proteid in nature.

The Organism and its Chemistry 109

comprehensive discussion of the problems of how organisms,
all of them., from the simplest unicellulars to the most com-
plex multicellulars, accomplish the chemical transformations
which they do accom])lish, would require a broader knowl-
edge of chemistry, both physico- and bio-chemistry than I
suppose any jU'ofessional chemist would pretend to have.
It would be, then, wholly presumptuous for one who like
myself is exceedingly meagerly possessed of first-hand chem-
ical knowledge even to touch it. Nor do I intend to do this
beyond the very simple extent of trying to present in schem-
atized fashion the various ways in which organisms operate
chemically, with the special end in view of presenting strik-
ingly to both naturalists and chemists what is in store
for them from the standpoint of research undertakings if
the ideas set forth in this chapter are to be realized.

Provisional Enumeration of Chemicot-naturaUst Inquiries

A rough-and-ready enumeration and classification of the
chemico-transformatory methods employed by organisms
may be given as follows :

1. The methods by which green plants use the radiant
energy of the sun in constructing their own substance, and
doing it in such fashion as to store away the great quanti-
ties of this energy that is characteristic of them.

2. The methods by wliicli plants utilize water and the in-
organic elements of the soil to their needs.

S. The methods by which plants store up organic sub-
stances for future needs in seeds, bulbs, roots, etc., and make
use of these supplies when the proper time comes.

4. The methods by which the organic foods of animals are
reduced to a state in which they can be taken into the cir-
culation.

5. The methods by which from the foods thus reduced the
substances of and in the tissues characteristic of particular

110 The Unity of the Organism,

species are built up; the methods, that is, of 'particular
as contrasted with general assimilation.

6. The methods, oxidative and otherwise, by which the
force liberated in muscular and other work is accomplished;
that is, the methods of particular as contrasted with general
work by organisms.

7. The methods by which the germinal elements of plants
and animals, sex-cells, plant and animal buds, gemmae, bulbs,
propagative cambium cells, etc., become so constituted as to
be able to develop into other individuals like those from which
they themselves originated.

8. The methods by Avhich the chemical substances dis-
tinctive of organic varieties, species, etc., are originally
produced, the phylogeny, in a word, of biochemical sub-
stances.

9. The methods by which acts of volition, memory, intel-
lection, and emotion are accomplished.

Peculiar Importance to Natural History of the Application
of Physical Chemistry to the Chemistry of Living

Beings

The ascertainment of details of structure and process
implied by this inventory obviously belongs to biochemistry
alone. By himself, the naturalist is helpless in his longings
for knowledge in these realms. But chemistry's initial
answer to the naturalist's appeal is not very comforting,
for if the particular chemist to whom the naturalist appeals
is broadly experienced and learned, is thoroughly objective-
minded, and quite frank, he assures the naturalist that his
request is for light in one of the darkest places in the whole
realm of chemical phenomena. Nevertheless, if plied closely,
chemistry is found to have a certain amount of positive
knowledge and certain well-supported conceptions which in-
terest the naturalist of the organismal cast of mind very

The Organism and its Chemistry 111

much — more, indeed, than they Interest the chemist himself.
This special interest of the naturalist in chemical facts and
ideas is due to his seeing possibilities in them that the chemist
sees but dimly if at all.

{a) Individuation and Speciiition of '^Organic Matter""
Fundamental Biologic Facts

That some physiologists are not fully awake to the sig-
nificance of certain of their possessions is shown, I think, by
the following appraisement of plant productions that are
used for drugs : "It is remarkable how great a variety of
these active substances are formed by plants. It seems
evident that they must be more or less accidental products
of chemical change. A very small number would suffice
for protection of the plant from being consumed by animals
for food. Similar conclusions may be drawn from the oc-
currence of adrenaline and a substance related to digitalir.
in the *paratoid' glands of a tropical toad, described by
Abel. It is impossible to see wiiat use to a toad a rise of
blood pressure in the animal which attacks it w ould be." -^

The naturalist must object to this view very strenuously.
In the first place, he is bound to point out the unquestioned
fact that these substances are subject to the law of hered-
ity, one of the securest and most probably universal of all
the laws thus far established by biology. Hence to pro-
nounce the substances accidental is to commit what may
justly be characterized as a scientific misdemeanor. Such a
pronouncement is about as unsound in the general living
realm as would be a declaration that the musical talent is an
"accidental" product in the human realm. The really mod-
em naturalist has outgrown the old practice of putting aside
whatever he can not explain as accidental or abnormal.

But the naturalist must go on and point out that if the
particular plant substances which have won the attention

112 The Unity of the Organism

of chemists because of their toxic or medicinal properties
may be regarded as accidental, then it would follow that an
incalculably vast array of the phenomena of the living world
taken as a whole would come under the same stigmatization.
This would follow from the fact that the thoughtful natur-
alist is certain that the criterion of accidental (to wit, that
of non-usefulness from the survival-of-the-fittest standpoint,
invoked by Bayliss) is no more applicable to these particu-
lar substances than to myriads of structures and substances
and activities of the most diverse sort presented by plants
and animals. To illustrate, probably a majority of all
organic odors, and all flavors so far as these are differen-
tiable from odors, would have to be cast into the scientific
discard of accidentals. In fact, I believe any open-minded
taxonomist to-day will recognize that such a criterion of
accidental would thus dispose of a majority, probably, of
the attributes upon which he depends for distinguishing
species, varieties, and races. And this brings up the ex-
ceedingly important question, is not such a physiological
conception as that expressed by Bayliss due largely to the
influence of the natural selection hypothesis, a conception
which came straight from natural history.? Bayliss's own
words seem to constitute an affirmative answer to this query.
But natural history is becoming convinced that while the
numerous activities of organisms which Darwin grouped to-
gether and named the struggle for existence are of very
great importance, they have very little originative power
in a strict sense. This conviction is being forced upon nat-
ural history from two of its main fields of research, namely
from that of taxonomy and that of genetics. The exact
taxonomic studies of to-day, especially such of them as
give due attention to the relation of the groups to their
environment, are at one with studies on mutation and Men-
delian heredity in denying to adaptation and natural selec-
tion the supreme role in evolution assumed by the Darwinian,

The Organism and its Chemistry 113

and especially the neo-Darwiniaii hypothesis.

Natural history, then, is able with a strength peculiarly
its own to deny physiology's right to set aside as accidental
myriads of biological phenomena in the interest of inorganic
hypothesizing about organic beings. Naturalists are in
position to insist that physical and chemical conceptions
as applied to organisms must be somehow so shaped that
they will neither disregard nor minimize the importance of
vast numbers of facts about the living world which natural
history from her own peculiar labors knows to be facts.

So the naturalist pushes his quest among his biochemical
confreres still more closely and broadly, for his general
scientific sense and faith lead him to surmise that some-
where chemistry has something better than the accident
hypothesis for dealing with the undeniable difficulties which
the individual, varietal, specific and generic substances and
activities present. Physiology almost certainly found the
right starting point or base of operations for a broader,
more adequate application of physics and chemistry to
biology when it recognized (as indicated on a previous
page) the fundamental difference between living and dead
protoplasm. Once the full significance of this difference
is recognized, biochemistry will be able to go ahead in its
sei*A^ice of biology — and of human weal in general — unham-
pered by hypotheses that are really narrowing because too
grasping.

Let me assure those biological readers whose scientific
thinking has been more or less deranged by the dread bogy.
Vitalism, that there is not the slightest real danger of run-
ning into Vitalism in the direction indicated. There is no
such danger because what we are here concerned with does
not raise the metaphysical problem of a Vital Force, or for
that matter of any other "ultimate force." The strictly
scientific problem before us is in deepest essence of the same
nature as it is in its most obvious, most practical expression.

114 21ie Unity of the Organism

It is this : Are a man and a dead man, a horse and a dead
horse, the same thing- or are they different things? If the
materiaHstic biologist and the fatalistic biologist will answer
this question with an unfaltering "They are different
things," and will give due attention to both the objective
and the subjective grounds on which the answer is based,
they will find that the words materialism and vitalisni, to
which they have clung so tenaciously, are emptied of any
important significance as applied to their doctrines. Both
vitalist and materialist will then become aware that the very
nature of biochemistry, its nature in virtue of which it has
a certain measure of independence, or self-sufficiency, is a
peculiar revealer of both the necessity and the method of
application of physical chemistry to biology.

So I bring this discussion of the organism and its chem-
ical substances to a close with a brief natural-history state-
ment of the probable role of physical chemistry in inter-
preting organic beings. First of all, we must insist that the
obvious, the never-refuted, the universal fact that all living
substance or protoplasm is individualized, shall not be ig-
nored or cavalierly tossed aside. Nor can we permit its
significance to be obscured by sophistical reasoning — by
such reasoning as, for example, may be indulged in from
the discovery that certain organs and cells may live for a
long time and carry on their activities more or less normally,
after being separated from the organism. What these
important observations prove is that many living organs,
tissues, and cells have wonderful tenacity of life, once theij
have been brought into existence. From this viewpoint
the facts are of great interest, but they do not furnish a
scintilla of evidence that organic substance or cells or or-
gans are independent of individual organisms in the sense
of being able to come into existence independently of in-
dividual organisms. Some physiologists talk about "organic
matter" as though it had as little connection with organ-

The Organism and its Chemistry 115

isms as has inorganic matter. "Living substance," unin-
(Hvlduated in a strict sense, has no better standing in the
world of objective reality than have the ghosts and other
a])i)aritions with which the imagination of primitive men
populates the world.

xVU the living substance that has existed on this earth
or anywhere else has existed through and in and because of
individual living beings. That this is a truism is no reason
for treating it as though it were not true.

(Z>) Indications That Variation and Inditiduatiou are
Primarily Chemical, While Constancy and Uni-
formity are Primarily Physical

Fixing attention, now, on organic matter as the matter
of individual organisms, which individuals are subject to
the laws of variation and heredity, and remembering that
according to these laws no two individuals are exactly alike,
and that every individual is derived from other individuals
which it resembles because of being thu;* derived, see how
in their very natiire physics and chemistry are adapted to
the needs of the natural historian in his efforts to interpret
the "matter" of the 'organisms with which he is occupied.
From being par excellence the science of transformation,
of the production of what is. absolutely different and abso-
lutely new relative to that from which the products come,
chemistry seems to the naturalist to be above all others
the science which ought to illuminate the variational, the
transformational, the productional side of "organic sub-
stance." On the other hand, from being par excellence the
science of the general, the persistent, the non- and quasi-
transformational side of natural objects, physics appeals
to the naturalist as the science which ought to bring light
into the darkness that envelops the repetitional, the like-
begets-like, the heredity side of the same substance,

116 The Unit I) of the Organisin

And since physics and chemistry have fused together as
regards many plienomena in their own special fields to pro-
duce a single two-parted science, physical chemistry, natu-
ral history looks with much hopefulness to this new science
for light on the "living matter" aspect of its problem. It
is almost certain that the application of physical chemistry
to the study of organisms has actually made a good start
in the very quarter which, as indicated above, the naturalist
would expect help from the new science.

As regards the Cell, biochemistry, prosecuted under the
guidance of physical chemistry, is bringing out facts and
formulating conceptions that are unmistakably organismal,
it seems to me, in their trend. Deferring to the biochem-
ist's predilection for the cell rather than for the organism,
let us reflect on how the problem of the cell presents itself
to the naturalist in one of its main aspects, that, namely,
of its eadstence only, that is, its phenomena other than those
connected with cell reproduction through division or other-
wise. The basal problem thus arising is : what Is the cell's
constitution in virtue of which it is able so to transform the
matter and the energy flowing through it as to enable it to
carry out the various activities, contraction, secretion,
conduction of stimuli and so on, peculiar to it, and at the
same time maintain its identity as a space-occupying object ;
that is, maintain its individuality.^

Place, now, alongside this formulation of the natural his-
tory problem of the cell's existence the following summary
statement of what the cell is to a biochemist who sees physico-
chemically : "But it is clear that the living cell as w^e now
know it is not a mass of matter composed of a congregation
of like molecules, but a highly diff*erentiated system ; the
cell, in the modern phraseology of physical chemistry, is
a system of co-existing phases of diff^erent constitutions.
Corresponding to the diff^erence in their constitution, dif-
ferent chemical events may go on contemporaneously in the

The Organism and its Chemistri/ 117

different phases, though every change in any phase affects
the chemical and physico-chemical equilibrium of the whole
system. Among these phases are to be reckoned not only
the differentiated parts of the bioplasm strictly defined (if
we can define it strictly) the macro- and micro-nuclei, nei-ve
fibers, muscle fibers, etc., but the material which supports
the cell structure, and what have been termed the meta-
plasmic constituents of the cell. These last comprise not
only the fat droplets, glycogen, starch grains, aleurone
grains, and the like, but other deposits not to be demon-
strated histologically. Tliey must be held, too — a point
wliich has not been sufficiently insisted upon — to comprise
the diverse substances of smaller molecular weight and
greater solubility, which are present in the more fluid phases
of the system, namely, the cell juices. It is important to re-
member that changes in any one of these constituent phases,
including the metaplastic phases, must affect the equilib-
rium of the whole cell system, and because of this necessary
equilibrium-relation it is difficult to say that any
one of the constituent phases, such as we find permanently
present in a living cell, even a metaplastic phase, is less
essential than any other to the 'life' of the cell, at least
when we view it from the point of view of metabolism." ^^

Or, again notice this : "For the dynamic chemical events
which happen within the cell, these colloid complexes yield
a special milieu, providing, as it were, special apparatus, and
an organized laboratory."

Some of the particularly important features of the "col-
loid complexes" which make them a "special milieu," i.e.,
a special environment, of so remarkable a character are:
The commingling in them of the solid and fluid, or "gel"
and "sol" conditions of the colloids ; the "surface effects" of
colloidal particles as the free surface energy, the osmotic
pressure, and perhaps the enzymic action, of such surfaces ;
the so-called adsorptive properties of solid colloids, that is,

118 The Unity of the Organism

the power the substances have, dependent upon temperature,
pressure, etc., to take up varying quantities of different sub-
stances, making them thus highly selective; and the ready
transformation of the substances back and forth from the
colloid to the crystalloid conditions to meet the needs of
the living cell.*

Such expressions as those quoted from Hopkins (and
others of similar purport could be quoted from other au-
tliors) it seems to me say merely this: The physical (in con-
tradistinction to the chemical) constitution of the living cell
is such as to enable it, as a complex unitary whole, to
accomplish the chemical transformations of substance and
energy which it is observed to accomplish, ^y its purely
physical properties, its spacial and energy magnitudes and
changes, the cell is primarily quantitative, while by its chem-
ical properties, its transfoniiation of substances and ener-
gies, it is primarily qualitative.

The physical principles implicated in organic phenomena
make of the cell an "organized laboratory," in Hopkins'
plirase, for bringing about ^Ulyncimic chemical eveuts,"'
events, that is, which are qualitatively transformative.

So our appeal as naturalists to physical chemistry for
help in interpreting tlie substances of which organisms are
composed is carrying us toward some such conception as to
tlieir individuation, apart from which we are obliged to con-
clude organic substance never exists, as that individuation
is dependent primarily on the chemical nature of the sub-
stance; while the continued existence of individuals and
their genetic repetition is dependent primarily on the phys-
ical nature of the substance.

This, I say, is the direction in which the evidence thus
far considered seems unmistakably to carry us. But we

* See especially The General Physical Chemistry of the Cells and
Tissues, by W. Pauli, in Physical Chemistry in the Sei'vice of Medicine,
translated by M. H. Fischer.

The Organism and its Chemistry

119

have not yet examined all tlie relevant evidence. For ex-
ample, what we have seen up to now does not go beyond the
cell in individuating the living substance. So a further stage
of our discussion will have to deal with the nature of the
cell and its place in the organic scheme.

REFERENCE INDEX

I.

2.
3.
4.

6.

7.

8.

9.
10.
11.
12.
13.
14.

Marshall 269 15.

Marshall 293 16.

Tangle 423; 327 17.

(a) Thierfelder ii. Stern 18.
370-385 19.

(b) Tangl u. Farkas. .624-638 20.

(c) Marshall 267-273 21.

Brooks 325 22.

Bavliss 19 23.

Hopkins 216 24.

Hopkins 217 25.

Deniker 109 26.

Hopf 240 27.

Beddard 254 28.

Wheeler 510 29.

Forel 46 30.

Fielde 1

Reichert iv

Reichert 144

Reichert 145

Reichert 326

Reichert 282

Reichert 139

Reichert 138

Arrhenius 295

Hertwig, O. ('12) 477

Marshall 6QQ

Marshall 366

Hardens 363

Taylor 343

Mathews 465

Bayliss 727

Hopkins 220

Chapter V
THE ORGANISM AND ITS PROTOPLASM

Protoplasm and Mystif^cation

NOT many words belonging to purely technical and de-
scriptive botany and zoology have become so much
involved as has "protoplasm" in obscure speculation on the
part of biologists themselves, and in more or less spurious
regard by both biologists and generally intelligent persons.
"The new Anthony studies the protean forms of life and at
the end is ravished by the sight of protoplasm. 'O bliss,'
he cries, and longs to be transformed into every species of
energy, *to be matter !' "

Though this is an undisguised bit of imaginative writing,
it undoubtedly expresses a feeling toward "the physical
basis of life" that in essence is no fiction. Many, perhaps
most, educated persons know its meaning in some degree
from personal experience. Whence this ravishment .^^ Justi-
fication for approacliing the protoplasm question from tliis
direction is found in the belief that the validity of what is
generally held to be strictly scientific observation and gen-
eralization is to some extent at stake.

Were Purkinje, Dujardin, von Mohl, Cohn, Schultze, and
the other discoverers of protoplasm thrown into any such
state of mind by what they saw? Not so far as any one
knows. Yet I do not for an instant believe these observers
were less sensitive to the deeper meanings of the phenomena
of organic beings than have been other persons, scientific
and non-scientific, who more recently have been affected much

120

The Organism and its Protoplasm 121

as St. Anthony was, on seeing or even hearing about proto-
plasm. Particularly may we believe Max Schultze, chief
among the pioneers in this realm, was not thus defective,
for we have explicit information that he was an artist as
w^ell as a scientist, and of a highly imaginative, sensitive
nature.^

Responsibility for the Mystification of Protoplasm

Great as was Huxley's service in enlightening the rank
and file of English-speaking people concerning matters bio-
logical,. I believe what he did for protoplasm in this way
by his renowned address, "On the Physical Basis of Life,"
he did partly at the cost of "making a Magic," as Kipling
would say, of protoplasm.

A soberly scientific discussion of protoplasm cannot pos-
sibly ignore the fact that in the light of the extensive exact
knowledge now in our possession, at least one excellent biol-
ogist has believed that it would be advantageous to give up
the word "protoplasm" altogether, so far as technical biol-
ogy is concerned," because at the present time it promotes
confusion rather than clearness of thought. And even those
who do not hold so extreme a view about the value of the
term, still admit that "on many sides the word is used in
different ways." For Max Schultze, to whose writings the
legitimate protoplasm doctrine probably owes more than to
any other one of the pioneers, the word had connected with
it a "quite definite conception." ^ Without taking grounds
one way or the other on the question of whether it is or
is not desirable to abandon the word, we will look at what
came to pass both as concerns concrete knowledge and in-
terpretation of the theory of protoplasm between 1861,
when Schultze wrote the phrase just quoted, and 1912,
when O. Hertwig last defended the right of the teiTn to exist
even though used in many different senses ; for by so doing

122 The Unity of the Organism

we shall come upon that which, to a large extent, has de-
termined the present writer's attitude toward protoplasm.

To begin with, there can be no doubt that, historically
considered, "protoplasm is a biological conception," as O.
Hertwig insists.^ Furthermore, equally certain is it that
when so considered it is a term of descriptive biology pure
and simple. The discoverers of protoplasm were engaged
in the enterprise of describing and comparing the minute
structure of animals and plants, no less avowedly than the
discoverers of the capillaries of the blood system were en-
gaged in the same enterprise. They were telling what they
saw under their microscopes and were drawing conclusions
from their observations. Even the titles of many of the
foundational memoirs of the protoplasm theory show this.

On the plant side, Corti (1772) was describing what he
saw in the interior of the living twigs of Chara; Meyen
(1827) what he could see in the fresh leaves of water-celery
{V allesnaria) ; Robert Brown (1831) what the living hairs
of the still higher plant Tradescantia revealed to him, and
so on. Similarly from the account left by Rosel V. Rosen-
hof (1755) of the examination of his "Proteus animalcule"
we know he had an amoeba under his microscope and was
studying it as he had numerous other organisms, low and
high, to find out how it was constituted. It was what seemed
to Dujardin (1855) the resemblance of the soft, living mate-
rial of the foraminifera examined by him, to the flesh of
liigher animals that made him propose the name sarcode for
this material. Finally, to mention no others of the many
whose observations contributed to the upbuilding of the
science of microscopic anatomy, it was Max Schultze's exam-
ination of the minute structure of a great range of animals
and animal tissues, from amoebae and the foraminiferae to
the muscles and retinas of the 'higher vertebrates, that fur-
nished the raw materials for his splendid inductions.

If we inquire how a strictly objective discovery concern-

The Orgaiiiam and its Pi'ofoplnsm 123

ing the structure of organic beings sliould have become
enveloped in so much sentimental, half-mystical interest, one
large element in the answer soon comes into view : it is due to
Huxley's address. Undoubtedly what contributed most,
historically, to the fame of this discourse was its populariza-
tion of the conception that life has, in deepest reality, a
physical basis. Both its good fame and bad fame have
rested largely on this.

I want to make it entirely clear that, important as this
aspect of the matter is, there is another aspect very dif-
ferent from this and almost as important, with which alone
we are concerned in this section. I refer to the conception,
not definitely expressed by the phrase, but obviously implied
in it as used both by Huxley and by nearly everybody since,
that "all life is one," and that the "seat" of it is the single
wonderful substance, protoplasm. Huxley's essay abounds
in sentences and phrases expressive of this notion: "Beast
and fowl, reptile and fish, mollusk, worm and polype, are all
composed of structural units of the same character, namely,
masses of protoplasm with a nucleus." ^ "With such qual-
ifications as arise out of the last-mentioned fact [the chlo-
rophyll function of green plants] it may be truly said that
the acts of all living things are fundamentally one." ^
"Hence it appears to be a matter of no great moment what
animal, or what plant, I lay under contribution for proto-
plasm [for food], and the fact speaks volumes for the
general identity of that substance in all living beings." "

Conception of Animal S arc ode and Plant Protoplasm as

''Identical Stuffs''

Since Huxley spoke (how far because he spoke it is im-
possible to say definitely) this notion has become a dogma,
having all the objectionableness of all dogma in science.
"Subsequently, Max Schultze and de Bary proved, after

124 The Umty of the Organism

most careful investigation, that the protoplasm and the
s arc ode of the lowest organisms are identical." ^ "However,
Max Schultze in particular . . . produced incontrovertible
evidence that the protoplasm of plants and animals and the
sarcode of the lowest organisms are identical stuffs." ^ "As
the culmination of a long period of work. Max Schultze, in
1861, placed the conception of the identity between animal
sarcode and vegetable protoplasm upon an unassailable
basis, and therefore he has received the title of 'the father
of biology.' " ^ "Protoplasm, the physical basis of life,
the living part of every living being, and essentially the
same in its general properties and functions in all. . . ." ^'^^

These quotations, picked up at random, will perhaps suf-
fice to illustrate the wide prevalence of the view. But though
widely held, acquiescence to it is by no means universal and
whole-hearted, judging from a considerable number of ex-
pressions that might be cited.

This not being the place to present in detail the facts and
arguments which make the conception of the absolute iden-
tity of all protoplasm untenable, I shall do no more than
put this question to those biologists who subscribe to the
creed : In the liglit of what we now know about the reactions
of the blood of animals of different genera and even species
to one another, and about the chemical composition of the
nitrogen-containing substances of tissues and elements in
different groups of organisms, if the protoplasm of a dog,
say, could be wholl}^ removed, and tliat of a fish or even a
tree could be substituted, would the dog continue to be the
same dog, and none the worse for the change? No biologist
untrammeled by speculative considerations will hesitate to
answer this negatively, unless, indeed, it seems too ridiculous
a question to deserve serious treatment. Yet if the "con-
ception of the identity between animal sarcode and vegetable
protoplasm" is warranted by what nature actually presents
to us, the answer would certainly have to be diametrically

The Organism and its Protoplasm 125

the opposite ; that is, it would liavc to be to the effect that
a dog would be strictly himself and as well off with a tree's
])rotoplasm as with his own sarcode.

But the particular point I want to bring out Is that, tak-
ing the utterances of not merely the father but the fathers
of modern biology at their maturest and best, one finds
that not only did they not teach the identity of protoplasm
in all living beings, but tluit what they did teach was some-
thing very different. Ferdinand Cohn, for example, said of
the protoplasm which he saw escaping through the cell-wall
of the alga studied by him, "if not identical" with animal
sarcode, it "must be at any rate in the highest degree anal-
ogous" to it. ^^

Max Scliultze''s Actual Teachings as to Protoplasm and

Sarcode

In 1861, after a great many trustworthy observations
had been made in widely separated portions of the organic
realm, of substances so closely resembling one another, came
Max Schultze with the essay which gained for him the widely
recognized title "the father of modern biology." Exactly
what did Schultze aim at in this essay .^ He was primarily
concerned with the nature of the cell and not of the jiroto-
plasm. The title chosen indicates this definitely enough :
"Concerning muscle corpuscles and that which has been
named a Cell." What he undertook was to dispose of the
then prevalent doctrine that the cell-wall is the most essen-
tial part of the cell, by proving that the body itself, not
the skin or membrane of the cell. Is the really important
thing; and partly by showing that even in cells having a dis-
tinct membrane, what is contained within it is similar to the
bodies of non-membranous cells and is the really active,
living part of the cell. His definition, "A cell is a little mass
of protoplasm In the interior of which lies a nucleus" ^^ epit-

126 The Unity of the Organism

omizes his results so far as concerns his understanding of
the nature of the cell. But while Schultze's central aim in
his essay was clearly to answer his own question, "Was is
das Wichtigste an einer Zelle?" the nature of that which is
the "Wichtigste" concerned him greatly although seconda-
rily; and for the topic now occupying us, the author's con-
clusions under this head are of the utmost interest.

(«) Cell Nucleus Distinct from Protoplasm But Both
Nucleus and Protoplasm Essential to Life of Cell

In the first place, it cannot be too strongly emphasized
that Schultze did not consider the cell nucleus to be proto-
plasm in any sense: "To the conception of a cell there be-
long two kinds [of things] a nucleus and protoplasm, and
both must be division products of corresponding parts of
another cell. Both constituents are equally important. A
disappearance of one, like that of the other, destroys the
conception of the cell." ^^

This unqualified recognition of nucleus and protoplasm as
"equally important" appears over and over again in the
essay, so even from this point of view it is obvious that
Schultze could not have subscribed to the conception that
"protoplasm is the physical basis of life." For him proto-
plasm could be no more this basis than the nucleus, and the
nucleus was not protoplasm. The expression which comes
nearer than anything else in the essay to the Huxleyan
notion reads: "The cell leads an exclusive (abgeschlossenes)
life, as one may say, the bearer of which is again preem-
inently the protoplasm, but there falls to the nucleus also
a role at least as significant although as yet not more defi-
nitely specifiable." ^*

This seeming ascription to the protoplasm of the place
of first importance in the life of the cell in no way contra-
dicts the conception of correlative essentiality of tlie nucleus-

The Organism unil its Proioplasm 127

But the most vital })oInt at wliicli the teachings of the
essay are contravened by the dogma that protoplasm is the
physical basis of life ; that is, that "all life is one" and that
its basis, protoplasm, is "essentially identical" in all living
beings, involves quite another matter than that of the rela-
tion between nucleus and protoplasm. That what Schultze
actually says comes far from implying such identity I shall
now point out. The crucial part of his discussion of the
relation between plant protoplasm and animal sarcode is
introduced by a brief reference to his studies, previously
published, on rhizopods. This reference he thinks important
as a starting point for the comparison, in that the rhizo-
pods furnish a solution to the "question of what in reality
the unfonned contractile substance of the Protozoa is."
He remarks that Sarcode, brought into prominence by Du-
jardin, had become discredited because given too wide and
indefinite an application. The term as used by Dujardin
was intended to apply to a "contractile substance which
can not be resolved into cells and which does not contain
other contractile form-elements, as fibers and so on." ^^ But,
Schultze contends, a substance of this sort is exactly what
we find the protoplasm of cells to be, and supports his con-
tention by instancing the contents of many plant and animal
cells, especially where, as in the cells of the hairs of Trades-
cantia, protoplasmic movements within the cell can be wit-
nessed. Concerning the substance of these cells, he says
there can hardly be a doubt that "we have to do here with
a contractile substance in the same sense as it constitutes
the body of many rhizopods." ^^ Since, then, Schultze rea-
sons, the term Sarcode was employed originally to designate
a substance which is now brought into the same category as
Protoplasm, "Sarcode" should be dropped.

128 The Unity of the Organism

(b) Recognized Common Attributes But Not Identity of

Protoplasm in All Organisms

It is clear that Schultze's central purpose was to com-
pare the contents of cells from widely different organisms
for the purpose of showing that as concerns some attributes
of these contents, that of contractility being foremost, the
substances agree with one another. We shall do well to be
attentive to the language in which this is expressed. As
to the protoplasmic movements within the hairs of Trades-
cantia and in the bodies of many rhizopods there can be no
doubt that we have to do with "contractile substance" "i?i
the same sense.^' For the point I wish to make I transfer
the emphasis from where the author placed it, namely on
"contractile substance," to "in the same sense." To affirm
or even to imply (neither of which the author's words do)
that the substances of two or more cells are the same in so
far as they are contractile, is very different from saying
that the substances are the "same" or "identical." And look
closely at another sentence: "The proofs for the relation-
ship of both substances have only multiplied by my own ob-
servations directed at this point." Note that a relation
between at least two substances, not a single substance, nor
yet two substances which are identical, is here talked about.

That there are other attributes than that of contractility
in which these substances agree is made sufficiently clear, and
it is on these attributes-in-common that the author bases
his proposal to attach to the word "proto))lasm" an "en-
tirely definite conception," and have it displace the word
"sarcode," to which, he says, no such conception has been
attached. But that the attributes-in-common possessed by
the protoplasm of different organisms comprehend all the
attributes of protoplasm, Schultze neither says nor implies.
On the contrary, several facts and arguments on which he
lays no little emphasis ought, I believe, to be interpreted as

The Organism and its Protoplasm 129

meaning that he conceived protoplasm to be essentially dif-
ferent in different organisms as concerns some of its at-
tributes. For example, after speaking of the differences
he had observed in two species of rhizopods of the same
genus, Gromia oviformls and G. Dujardinia, he says, "I
bring this forward only in order to point out in indubitable
cases of naked protoplasm differences again in movement,
consistency, and tendency to fuse with like substances with
which it comes into contact, upon which differences we come
again in the naked cells of the tissues of higher animals."
The immediate point Schultze was aiming to establish here
was the indi^^duality, in the sense of presers^ation of iden-
tity, of the protoplasmic mass which he was contending to be
the essential thing in the cell, without the presence of a
membrane or any sort of limiting outer la3'er to insure that
individuality ; so it is only secondarily that his argument
touches upon the attributes of differentiation of the proto-
plasm itself as between different cells. Nevertheless his in-
sistence in several connections on the differences, particu-
larly in consistency and resistance of the protoplasm, surely
bears strongly in this direction. I believe, then, enough has
been said to show that the conception of protoplasm held
by the "father of modern biology" gives no warrant for the
Huxleyan and more recent conception of the essential iden-
tity of the protoplasm in all organic beings.

Ernst Brucke''s Conception of the Cell as an Organism

Another essay recognized as constituting part of the
classical literature of modern biology is Ernst Briicke's
"Die Elementarorganismen." This essay is likewise particu-
larly important for our enterprise, though in a considerably
different way from the one just examined. Although
Briicke's labors lay so largely in the same field with those
of Schultze, and although he was familiar with his con-

130 The Unity of the Organism

frere's writings, significantly enough the theses he upheld in
this essay led him to regard somewhat lightly Schultze's
leading contention, namely, for the importance of the cell-
contents, protoplasm and nucleus, as against the cell-mem-
brane. That the cell should be regarded as an organism
was, as is well known, what Briicke undertook to show, and
his motive should be distinctly recognized. He was working
in the interest of observational and descriptive histology and
physiology. Nothing in this essay, at least, indicates that
he was particularly interested in the broader implications
of his main thesis, and there is much, as we shall presently
see, to show that he was decidedly wary of "ultimate ques-
tions."

Tlie very word "organism" implies organization, and
organization implies some thing organized ; something, that
is, composed of parts a number of which, at least, are in-
dispensable and correlated with one another. An organism,
then, or an organized thing, and a thing of ultimate sim-
plicity, are tenns not only contradictory but are mutually
annihilative of meaning. Briicke does not say this in just
this language, but his whole argument is a setting forth of
the idea in a concrete, particular case, namely that of the
cell. After calling attention to the similarity of the cells
to the organism in various attributes, as that of growth
by ingestion of foreign material, movement, change of form,
response to stimulation, and so on, and after reminding us
further of the fact that organisms are composed of parts
which we call organs and systems of the body, he says, "We
can hardly think otherwise than tliat in the cell also the
different activities proceed from differently constructed
parts." ^^

Going further with this idea, he writes : "We naturally
do not expect that the organs and systems repeat themselves
as we find them in the human organism taken in its entirety.
We know this is no more the case even in the lower animals.

Tlie Organism and its Protoplasm 131

\Vc know that witli reduction in dimensions nature changes
the means bj which the energies of the inorganic world are
made serviceable in the organism. But with the exception of
the differences conditioned by this fact, and with the ex-
ception of tlie less number of constituting parts, we have
no right to liold one of these smaller organisms as less
ingeniously constructed than one of another or greater di-
mensions, and this consciousness we ought to bring not only
to the investigation of the smallest animals, but likewise to
the investigation of plant and animal cells. We may always
see in the cell a small animal body, and ought never to
lose sight of the analogies which exist between it and the
smallest animal forms." ^^

Characteristic Organization in All Cells

But it is in connection with the problem of the more de-
tailed structure of all parts of the cell, membrane, nucleus,
and cell-body alike, that this investigator's conclusions and
attitude of mind are most fully revealed, his great point
being that there must be far more of organization in the
cell than microscopes reach. "What right have we to be-
lieve," he says, "that in our scheme we have exhausted the
organization of the cell.^ Is it a ground for such an as-
sumption that we can perceive no further details in the
relatively giant retinal image given us by our present high
magnifications? . . . Shall we conceal from ourselves the
fact that many circumstances limit the field of our mi-
croscopical determination?" ^^

In \'iew of the fact that later speculative biologists have
appealed to Briicke's contention that there must be cell or-
ganization beyond that revealed by the microscopes, in sup-
port of their fancied "ultimate biological units," it should
be emphatically pointed out that not only does Briicke's ar-
gument not give passive sanction to such hypotheses, but

132 The Unity of the Organism

rightly interpreted it opposes them. He does indeed main-
tain that molecular structure als known to the chemist
can not be the only kind which eludes observation. "These
molecules," he says, are "not merely building stones placed
one beside the other in a simple fashion, but are united to-
gether in an ingenious {kanstreich) living organization." ^'^

And referring back to the paragraph quoted, in which
the differences in structure between small and large or-
ganisms are dwelt upon, we find an unmistakable indica-
tion that the mode of conceiving, as one may say, which
Briicke would hold, might be legitimately applied to the
ultramicroscopic structure of org^yiisms : "We may always
see in the cell a small animal body and ought never to lose
sight of the analogies which exist between it and the smallest
animal forms." -^ That is, each living cell at any and every
moment has organization of its own beyond what we can see
with the microscope, the organization being analogous to
that which exists in the smaller animals. No vagaries here
about an organization in one cell (a germ cell) which rep-
resents the visible organization of some other cell-organism
developed from that cell.

In another passage Briicke sounds a warning about theo-
rizing in this domain of biology which, had it always been
heeded, would have prevented much wandering about in a
morass of speculation. "Desirable as it is," he says, "al-
ways to hold rigorously to immediate observation, equally
necessary is it not to close the spiritual eye to that which
is inaccessible to observation, so that we overprize the work
of our microscopical determinations and with the help of
final words {Schlagworter) — cell-membrane, cell-contents
and cell-nucleus, erect physiological doctrines which a fu-
ture generation may refuse recognition." ^^

To be sure, the author was aiming in this at doctrinal
perils considerably different from those of recent "repre-
sentative biological units," but the essence of bis warning

The Organism and its Protoplasm 133

is applicable in the one case as in the other. He would have
no pseudo-scientific explanations, whether hidden behind
'^ Schlagworter'" or entities of the pure imagination, given
a semblance of objective reality by being connected with
actual objects. One of the great merits of Briicke's attitude
toward the problem of the constituents of the living beings
which lie beyond the reach of direct observation should be
specially pointed out, though this is not the place to speak
of it in detail. From several of his statements, but par-
ticularly from that about the analogies between the cell and
the smallest animals, we may infer that he had a genuine
appreciation of the distinction there is between the concep-
tion that there must be some sort of organization beyond
what the microscope reveals, and a conception of what the
specific nature of that organization is in particular cases.
So a critical examination of Briicke's fundamental essay
reveals the fact that though starting from a quite different
standpoint from that of Max Schultze it contains as little
as does Schultze's essay to support belief in the identity
of protoplasm in all living things.

Results of Later Description and Classification of Cell

Substances

The question still to be considered is whether or not the
discoveries made since the pioneer era have furnished, by
the actual study of protoplasm, more support for the be-
lief in such identity. I do not believe any candidly critical
student will maintain that they have. On the contrary I
believe such a student will recognize that the indubitable
tendency of the evidence is toward the opposite conclusion ;
namely, that the protoplasm not only of all organisms, but
of many different parts of the same organism, is to some
extent different.

That the observational knowledge of the substances con-

134 The Unity of the Organum

stituting living organisms has been vastly increased since
Schultze and Briicke wrote, hardly needs affirmation. This
greatl}^ augmented store of knowledge may well be regarded
for a moment in the light of the circmiistances referred to
some pages back. One outcome of later work has been a
serious questioning of the scientific desirability of longer
retaining the word "protoplasm." To , be sure, this ques-
tion was not raised primaril^^ because of interpretations of
the substance of the cells of different organisms, but rather
because of interpretations placed upon different substances
in the same cell. Strasburger, who seems to have been the
first to depart from Schultze's sharp distinction between the
protoplasm of the cell and the nucleus, was led to this by
determinations made largely by himself, which had accu-
mulated during the two decades of research since Schultze
wrote, that the nucleus is by no means the simple, homo-
geneous thing it appeared to the earlier investigators, but
has itself an elaborate organization, portions of which re-
semble protoplasm in many respects.

Not without significance is the fact that beginning about
the same time the custom has grown up of using the term
plasm or plasma instead of protoplasm. It is not unusual
to regard these words as exactly synonymous, and to sup-
pose the only advantage in plasma is its brevity. Obviously
the term is more non-committal in meaning than is proto-
plasm, the idea of a ^^first formed substance" being undoubt-
edly very different from that of merely a ''formed sub-
stance." But Strasburger's proposal went further than
merely to name the whole cell substance protoplasm. He
proposed to replace it by cytoplasm for that part of the
cell to which alone Schultze had applied the word proto-
plasm, and to call the portion in tlie nucleus micleoplasm.
This last, being a mongrel word, was soon replaced by
haryoplasm.

In other words, the change in the scope and meaning of

The Organism and its Protoplasm 135

terms introduced the really more significant thing, namely,
that of a definite effort toward a scientific classification
of the constituents of the cell, this being based upon and
necessitated by tlie fuller and exacter descriptions of the
cell that had been reached.

This brings us to wliere we can formulate more closely
the question now before us : Do the descriptions fully agreed
upon at the present day, of the substances entering into
the constitution of living beings, warrant the belief that a
single substance, under whatever name, is the basis of life,
and is identical for all organisms? No one should fail to
notice the two parts of the question: (1) Is there a single
substance which is the basis of the whole life of any one
organism? (2) If this were answered affirmatively, would
that substance be identical for all organisms?

(a) Cytoplasm and Karyoplasm Differentiated Areas of a

Common Basic Substance

Several competent investigators in this department of
biology have summarized both the observational and the
interpretative knowledge now in our possession. A liberal
appeal to these summaries will furnish a direct and sure
answer to the first part of the question, and an indirect
though hardh' less sure answer to the second part. To be-
gin with, I quote from Wilson, the first point to be brought
out being that of the relation between the nucleus and the
rest of the cell. "Careful study of the nucleus," he says,
"during all its phases gives, however, reason to believe that
its structural basis is similar to that of the cell-body ; and
that during the course of cell-division, when the nuclear
membrane usually disappears, cytoplasm and karyoplasm
come into direct continuity. Even in the resting cell there
is good evidence that both the intranuclear and the extra-
nuclear material ma}^ be structurally continuous with the

136 The Unity of the Organism

nuclear membrane. . . . For these and other reasons the
terms 'nucleus' and 'cell-body' should probably be regarded
as only topographical expressions denoting two differen-
tiated areas in a common structural basis. The terms kary-
oplasm and cytoplasm possess, however, a specific signif-
icance owing to the fact that there is on the whole a definite
chemical contrast between the nuclear substance and that of
the cell-body. . . .

"Both morphologically and physiologically the differen-
tiation of the active cell-substance into nucleus and cell-body
must be regarded as a fundamental character of the cell
because of its universal . . . occurrence, and because there
is reason to believe that it is in some manner an expression
of the dual aspect of the fundamental process of metabolism,
consti-uctive and destructive, that lies at the basis of cell
hfe." 22

So far as I am able to make out, authorities are in essen-
tial agreement as concerns the directly observational part
of this statement touching the relation between nucleus and
cell-body. The general conclusion is that, keeping an eye
on the actual structure of the cell and ignoring for the
moment the system of naming applied to the different parts,
Schultze and Strasburger were both right ; Schultze in hold-
ing that there is something fundamental in the distinction
between nucleus and cell-body, and Strasburger in holding
tliat there is something fundamental in the kinship between
the two. Interpretatively, therefore, the question resolves
itself into one of naming and classifying what is observed,
and there can be no doubt, as Wilson and a majority of
recent authors liave recognized, not only of the convenience
but of the scientific soundness of using the term plasm for
the living substance of the cell as a whole, and then des-
ignating the kindred but yet different kinds of plasm by
the terms karyo plasm and cytoplasm.

The Organism and its Protoplasm 137

(b) Details of Cytoplasmic Structure

Concerning the details of structure of these two main
classes of cell material, Wilson writes: "As ordinarily seen
under moderate powers of the microscope, protoplasm ap-
pears as a more or less vague granular substance which
shows as a rule no definite structure. More precise exam-
ination under high powers, especially after treatment with
suitable fixing and stahiing reagents, often reveals a highly
complex structure in both nucleus and cytoplasm. Since
the fundamental activities of protoplasm are everywhere of
the same nature, investigators have naturally sought to
discover a corresponding fundamental morphological or-
ganization common to all forms of protoplasm and under-
lying all its special modifications. Up to the present time,
however, these attempts have not resulted in any con-
sensus of opinion as to whether such a common organization
exists. In many forms of protoplasm, both in life and
after fixation by reagents, the basis of the structure is a
more or less regular framework or meshwork, consisting of
at least two substances. One of these forms the substance
of the meshwork proper: the other, often called the grownd-
suhstance, (also cell-sap, enchylema, hyaloplasma, parami-
tome, interfilar substance, etc.), occupies the intervening
spaces. To these two elements must be added minute, deep-
ly-staining granides or 'microsomes' scattered along the
branches of the meshwork, sometimes quite irregularly, some-
times with such regularity that the meshwork seems to be
built of them. Besides the foregoing three elements, which
we may provisionally regard as constituting the active sub-
stance, the protoplasm almost invariably contains various
passive or metaplastic substance in the form of larger gran-
ules, drops of liquid, crystalloid bodies, and the like. These
bodies, which usually He in the spaces of the meshwork, are
often difficult to distinguish from the microsomes lying in

138 The Unity of the Organism

the meshwork proper — indeed, it is by no means certain
tliat any adequate ground of distinction exists." ^'"^

(c) Three Main Theories of the Structure of Protoplasm

Wilson then sets forth in general terms the three lead-
ing interpretational views of the nature of what is here
described ; that is, the well-known reticular or filar theory,
the alveolar theory, and the granular theory. It may not
be superfluous to state briefly what each of these theories
is. The reticular theory interprets what is seen in the
protoplasm in its simplest form, as a network of actual fi-
bers which branch and anastomose with one another so as
to make, according to the familiar comparison, something
like the network of a sponge, the spaces within the retic-
ulum being filled by the fluid or semi-fluid portions of the
protoplasm. This view holds that the granules, supposed
by the older observers to be essential constituents of the
protoplasm, are the angles where the threads join, the
threads seen end-on, and in some cases true granules at-
tached to the threads. The alveolar theor}', proposed and
defended with great detail of observation and argument by
O. Butschli, compares the protoplasm with foam rather
than with a sponge. It contends that protoplasm consists
of separate, closely crowded minute drops of a liquid alve-
olar substance suspended in a continuous interalveolar sub-
stance, likewise liquid, but of diff'erent nature. According
to this interpretation what are taken by the reticular
theory to be fibers are the walls of the alveoli, there being
in reality no fibers present. The granular theory holds
that granules of various sizes and nature are the fundamen-
tal constituents of protoplasm, the fluid and the semi-fluid
parts, as also the fibers whenever present, being of sec-
ondary significance.

The (Jrcjaifism cnuj its Protopinsjn 139

(d) ''No Unwersal Formula for Protoplasmic Structure'*

Finallj^ summing up his own conclusions regarding these
tliree theories, Wilson says: "]\Iy own long-continued stud-
ies on various forms of protoplasm have likewise led to the
conclusion that no universal formula for protoplasmic struc-
ture can be given. ... It is impossible to resist the evi-
dence that fibrillar and granular as well as alveolar struc-
tures are of wide occurrence ; and while each may be char-
acteristic of certain kinds of cells or of certain physiological
conditions, none is common to all forms of protoplasm. If
this position be well groimded, we must admit that the
attempt to find in visible protoplasmic structure any ade-
quate insight into its fundamental modes of physiological
activity has thus far proved fruitless. We must rather
seek the source of these activities in the ultramicroscopical
organization, accepting the probability that apparently
homogeneous protoplasm is a complex mixture of substances
which may assume various forms of visible structure accord-
ing to its modes of activity." -^

And so we have this excellent authority's answer to the
first part of the question above formulated : The knowledge
we now possess derived from observational studies on the
minute structure of organic beings does not warrant the be-
lief that there is a single substance which is the basis of the
whole life of any one organism.

But if the facts do not warrant such belief what possible
ground is there for the doctrine of the identity of proto-
plasm in all organic beings? Were there no other evidence
against it than this drawn from the microscopical morphol-
ogy of organisms, here alone is sufficient evidence to banish
the dogina completely and forever from scientific biology.
But as we see in other sections of this treatise, particularly
those on the organism and its chemical compounds, there
are even more compelling e^adences against the doctrine than
those here passed in review.

140 The Unity of the Organism

Preliminary Remarks on the Bearing of Physical Chemistry

on th£ Protoplasm Doctrine

The theorj^ of protoplasm as the living substance, as
though there were a single substance identical in all or-
ganisms and in all parts of the same organism, has passed
into a new and peculiarly subtle stage during the last two
or three decades. This has been one of the results of the
application which was sure to be made of physical chemistry
to biological phenomena.

An understanding of what is implied by this will be
facilitated by reflecting on some of the most obvious dif-
ferences between physics and chemistry, and on what phys-
ical chemistry as contrasted with chemistry pure and
simple is ; that is, chemistry as it was prior to the rise of
physical chemistry. But since we are invading a perilous
realm, one in which diverse and strenuously contested views
prevail, we must confine ourselves to what is most obvious.

That that vast series of transformations of natural sub-
stances which occur when two or more of the substances
come together under certain conditions, so profound that
the new substance is wholly different from the originals, are
real objective phenomena, and are the bases of the science
of chemistry, no one will gainsay however unqualifiedly he
may be committed to the theory that these phenomena be-
long to the domain of pliysics after all. The reality of the
transformations, and hence the reality of the discrete, in-
dividuated bodies or substances, both those entering into the
combinations and those arising from the combinations, is
what especially concerns us. Whether the combinations and
transformations are influenced by physical as contrasted
witli cliemical forces, and what names and classifications
shall be employed in dealing witli tlie phenomena, are of
very secondary importance to this discussion.

On the other hand, that there Is an almost if not quite

The Organism and its Protoplasm 141

equally vast series of phenomena presented by natural bod-
ies and substances which do not involve such combinations
and transformations and which are the basis of the great
science of modern physics, will also probably be accepted
without cavil. But tlie point to be specially noticed is that
since physics as tlius indicated is primarily concerned with
those attributes of bodies and substances which are common
to very great numbers of them, and are not only common to
them but while rendering the bodies subject to great change,
do not make them subject to complete transformation, the
discrete, the individuated bodies fall much into the back-
ground.

Physics is preeminently from its vei'y nature an individ-
ual-ignoring science. Concentrated as its attention is, on
the force of gravitation for example, or on the behavior of
light, and finding these manifested almost everywhere re-
gardless of how many kinds of bodies are concerned, it is
not surprising that the habit should be formed by persons
who devote themselves to studying these phenomena, of neg-
lecting almost entirely the bodies themselves which have
weight and emit and receive light. Then when this habitual
tendency to neglect the bodies finds encouragement by well-
reasoned hypotheses that the bodies are actually less im-
portant and real than certain essences or entities "behind"
them, the ignoring of the bodies passes easily from the realm
of habit to that of dogma, and such strange conceptions of
the "Province of Physics" as the following arise: "If further
we give the name thing to that with the objective existence
of which we are acquainted by our senses, then it follows
that in the physical universe there are only two classes of
things; to these the names Matter and Energy are given." ^^
That protoplasm, of just such a conceptual character as
we are pointing out in this chapter does not exist, would
obviously be acceptable to a physics holding such an unob-
jectificd, denatured conception of nature as that just

142 The Unifij of the Organism

quoted. If there are "only two classes of things" in the
universe, "flatter and Energy," it would follow that the
myriads of individual organisms which according to our
senses certainly seeTU to exisi^ are after all phantasms of
some sort, and those departments of science which deal with
the phantasmal individuals would have to concern them-
selves chiefly with "getting behind" the apparitions to the
two real things, the Matter and the Energy.

But even those physiologists and biologists who adopt the
physical-chemistry standpoint most unreservedly speak of
the matter of which organisms are composed as "living"
and so do not quite accept the restrictions upon them of
such a conception of the "province of ph3^sics" as that
formulated by physics itself in the quotation above given.
They seem to insist by implication that "living matter" is
a real thing, no less than are Matter and Energy. This is
very significant from our standpoint and will be exceedingly
important if finally physics, too, shall fully accept it. It
will be thus important because if biology is driven, as this
treatise holds it will be, to recognize that the individual or-
ganism, each and every one that exists or ever has existed,
is as real a thing as are any of its parts or substances, by
whatever criterion of reality science or philosophy can ap-
ply ; and if physics goes with biology in this, then will ob-
jective science as a whole be committed to a doctrine of the
universe vastly different from that which now dominates the
physico-mathematical sciences. Put into the briefest, most
concrete form possible, such a consummation would establish
the" so-called natural history, or descriptive, or "inexact"
(sic?) sciences in a place at least as secure and exalted as
that held througli the centuries in western civilization by
the mathematico-physical, the so-called exact sciences.

And we must not forget tlie important fact that physics
itself as conceived by some of its eminent devotees, occupies
no such all-inclusive, all-dominating and domineering place

The Organism and its Protoplasm 143

in the liicrarchj of the sciences as that implied by the quo-
tation given above. Thus : "Physics in the largest sense
of the word is the science of unorganized matter and the
phenomena which it manifests. These phenomena are called
physical phenomena. All the other sciences which occupy
themselves with matter, have to do with organized substance
(the biological sciences)." ^*^

The whole-hearted recognition by physics as thus con-
ceived, of matter in two fundamentally different conditions,
these giving rise to two coequal realms of science, places no
obstacles in the way of biology's bringing into clear view the
significance of individuals as natural phenomena. That
physical chemistry can be of enormous service in the inter-
pretation of living beings if only it docs not claim too much
for itself, if it recognizes physiologico-, or better bio-
chemistry, to be on a par with itself, we shall see to some
extent in later chapters.

Experimental Evidence of the Specificity of Protoplasms

Up to this point the burden of the facts and arguments
of this chapter has been in a sense negative. It has been in
opposition, merely, to the generalization that protoplasm
is one and the same thing in all organisms. Although rela-
tively few researches in microscopic comparative morphology
and embryology have been carried out with the avowed pur-
pose of discovering in how far each organism or group of
closely related organisms has its own fundamental sub-
stances, the few which have been made have yielded highly
significant results and open the gate to an alluring realm for
future exploration.

{a) Greater Fusibility Between Closely Related Species, as
in Tissue Mixtures and Grafts

The morphological investigations which will, perhaps, be
most crucial when carried far enough, are those on the fusi-

144 The Unity of the Organism

bilitj of naked protoplasm from different organisms — from
different individuals of the same and of different species.

The experiments of H. V. Wilson on the coalescence of
dissociated cells of sponges and hydroids particularly, have
blazed a seemingly very practicable manipulative path into
the subject. Wilson cuts portions of the animals into small
pieces, then squeezes these through bolting cloth. This
operation separates the tissues into small groups of cells,
and to some extent into completely isolated cells. These
cells, kept under favorable conditions, soon assemble together
into compact masses, and from the masses normal animals
frequently develop. Although Wilson has thus far been
chiefly occupied with showing that various animals are able
within their own species to rehabilitate themselves under
such conditions, he has not failed to raise the question of
how far coalescence and normal development may take place
when tissues of different species are mixed together. His
experiments under this head are far less extensive than those
on the commingling of cells from different individuals of the
same species, but are nevertheless highly instructive. In his
paper of 1907 his statement, "Unlike specific substances
(protoplasms of quite different species) do not tend to
fuse," ^^ is perhaps a somewhat more unqualified denial of
the fusibility of the protoplasms of different species ; or
stated affirmatively, a somewhat more unqualified assump-
tion of the specificity of the protoplasms of each species
than the observations presented by him in a later publication
justify.

But if this much of restriction upon his conclusions may
be necessary, there still remains evidence of the most con-
vincing sort in his results of the specific nature of the pro-
toplasm of different species. The only details he has so
far given of his negative results are contained in his report
on sponge culture to the Bureau of Fisheries. In this he
describes experiments on intermingling the tissues of Micro-

The Organism and its Protoplasm 145

ciona prolifera, witli those of Lissodendoryx carolinensis^
and M. prolifera with Stylotella heliophila. In both cases
the larger fragments were discarded, and only the cells and
small cell masses experimented with. These were thoroughly
mixed together in watch glasses by jets of water from a
pipette. "The mixture was spread evenl}^ over the bottom
of tile watch glass, and looked like a fine sediment." But
the cells of each species could be readily distinguished, those
of Lissodendoryx being greenish and those of Microciona
being briglit red (to speak of these two species). "Fusion
began, and the bottom w^as soon covered, no longer with a
continuous 'sediment' but with discrete small masses, some
red, some green. ... In general red mass fused with red
mass, and green mass with green mass. Nevertheless fusion
was also observed in some instances betw^een red and green
masses. . . . Such fusions, as the further history of the
watch glass showed, must have been temporary or the com-
bined masses soon died. For as fusion progressed and the
masses increased in size, the distinction between red and
green tissue became more evident." -^ The outcome was
that, young sponges of pure Microciona were developed but
none of Lissodendoryx, the development going no further
than the early fusion stages. Likewise in the mixture of
Microciona and Stylotella there was no fusion between the
cells of the two species nor was there a full development of
Stylotella sponges alone.

The point wherein these negative results are somewhat
less conclusive than might be wished is that neither in Lis-
sodendoryx nor Stylotella were full fledged young sponges
produced from the dissociated tissues even when these were
treated each species by itself. It may be said that a fusion
of two species could not be expected if one of them is in-
capable of fusion and development alone. Nor is this ob-
jection fully met by the fact that in one of the species at
least, Lissodendoryx, the early stages, that is the fusion

146 The Unity of the Organism

stages, do occur. To make the case quite satisfactory fail-
ure to fuse ought to be shown between species both of which
are able, and about equally able, to develop into typical
animals of their own species.

But the evidence of specificity of the protoplasm of the
different species indicated by the experiments is by no means
restricted to the nonfusibility of the cells of the several ani-
mals. Quite as conclusive is difference in behavior of the
various preparations. Although Wilson does not go into
this particularly, his experiences show that the tissues of
Microciona produce young sponges considerably more read-
ily than do those of the other species when treated in exactly
the same manner. As to the relative viability and develop-
ability of dissociated cells of Lissodendoryx and Stylotella
the descriptions are not full enough to enable one to decide.
A comparison of the species on the basis of quantitative
determinations of both the extent of development and the
conditions of the water under which the development takes
place would probably settle this and would be highly in-
structive.

Another investigator, Karl Miiller, reports that the dis-
sociated cells of individuals of different species are able to
fuse together but that the fusion masses "never regenerate
to small sponges." No details are given under this head,
but are promised in a later publication.

Obviously the fusibility or non-fusibility of isolated tis-
sues as brought out by experiments of this kind are phe-
nomena close of kin with those of the degree of compati-
bility of grafts in the ordinary sense with the "stock" upon
which they are grafted. It was mentioned in another con-
nection that we now have sufficient information about graft-
ing in animals to show that much the same rules hold here
as among plants.

Morgan reviews the work that has been done in animal
grafting, and sums up the results on the congeniality be-

The Organism and its Protoplasm 147

twecii different kinds as follows: "The general statement
may be made for both cases [grafting and fertilization] that
closely related species combine more readily than those far
a])art, i.e., the results are more successful for unions be-
tween closely 'related' forms than between distantly 'related'
forms. Certain exceptions exist, however, in both direc-
tions." ^^

But while the fusibility or non-fusibility of the tissues of
diff'erent animals as revealed by Wilson's methods are phe-
nomena closely related to the compatibility or non-compati-
bility of scion and stock in plant grafting, the former would
seem to be, so far as the methods can be emploj^ed, a con-
siderably better test of the specificity of the protoplasms
of different individuals and species. This is so because by
comminuting the animals, as Wilson does, and then thor-
oughly mixing the elements, every part and kind of substance
of the one may be supposed to be brought into contact with
every part and kind of substance of the other, whereas in
grafting only a relatively small portion of the scion can
actually touch the stock, and generally speaking only in
such manner that the corresponding kinds of substance i.e.,
corresponding tissues, come together. From this it may well
be, that there is really more specificity of substances in the
ordinary graft than might at first thought be inferred from
the perfection of the union. Actual fusion may occur only
between some substances of each party to the union, and
the general life and activities of the graft may be kept up
through its ordinary metabolic processes, it, however, using
as food to some extent, substances received from its host,
instead of wholly from the outside world.

Indeed some such interpretation as this appears to be
necessitated by the strict maintenance of type of both
graft and host. From this standpoint a successfully grafted
individual plant or animal might be defined as a partnership
in which each partner while maintaining most of its own

148 The Unity of the Organism

former individuality still supplies to the others certain es-
sential food substances from its own body and activities es-
sential to the other. The relation between the two organ-
isms which are grafted together seems similar in important
respects to the relation between two organisms living to-
gether symbiotically. In fact, a graft combination might
be spoken of as an artificial symbiosis. On the whole, then,
the morphologico-physiological study of the ability of or-
ganisms to fuse together bodily points unmistakably to the
belief that different kinds of organisms must contain in their
make-up certain fundamental substances that are different
as well as certain others that are very much alike if not
quite identical. In other words such studies furnish no
warrant for the conception of a physical basis of life identi-
cal in all living beings.

{h) Protoplasms, Not Protoplasm, Must Be the Form of the

Protoplasmic Conception

Studies of this kind show that if the term protoplasm is
to have any scientific usefulness it must be used in the plural
— protoplasms — and so must be subject to the practices
and principles of biological description and classification in
the same way that all other biological entities are, and the
great and ever-increasing munber of elements now known
with more or less definiteness as entering into the makeup
of living substance must, I believe, be looked at in this light
by all departments of biology as w^ell as by natural history.
Protoplasms are the substances of which individual or-
ganisms are composed, so the protoplasms as well as the
organisms must be individuated.

To set forth the facts and reasonings upon which such a
conception of protoplasm must rest is one of the foremost
objects of several of the discussions in this treatise. Those
on the organism and its chemistry, and the organism and its
cells, are especially dedicated to this end.

The Organism and its Protoplasm

149

REFERENCE INDEX

1. Locy 273 16.

2. Hertwig, O. ('95) 12 17.

3. Schultze 17 18.

4. Hertwig, O. ('12) 12 19.

5. Huxley ('68) 140 20.

6. Huxley ('68) 138 21.

7. Huxley ('68) 148 22.

8. Hertwig, O. ('95) 7 23.

9. Hertwig, O. ('12) 8 24.

1 0. Needham 88 25.

11. Geddes 829

12. Schultze 11

13. Schultze 23 28.

14. Schultze 11 29.

15. Schultze 16

Schultze ir

Briickc 387

Briicke 383

Brucke 386

Briicke 387

Brucke 385

22

23

27

1

26. Chwolson 1-2

27.

Wilson, E. B.

Wilson, E. B.

Wilson, E. . B.

Watson

('00).
('00) .
('00).

Wilson, H. V.
Wilson, H. V.

('07)
('10).

257
14

Morgan ('07) 298

Chapter VI

THE ORGANISM AND ITS CELLS

What the Cell-Theory Is, Viewed Historically and

Substantiiyelfj

(a) Importance and General Character of the Theory

THE cell-thcorj seems to some biologists second to the
evolution theory alone in its importance to biological
science. This may be too high an appraisement ; but beyond
question it is and ever will be one of the most influential
generalizations yet reached by the science.

(h) Various Forms of the Theory as Currently Held

The views of tlie cell incident to our general standpoint
necessitate a critical consideration of the theory. What,
exactly, is included in it ? Does it contain more than one
crucial idea? If so are all equally well grounded in observa-
tion? Clearly it has differed considerably in both scope and
specific meanings at different times and for different authors.
The formulation of it by Theodor Schwann, generally re-
garded as its founder, undoubtedl}^ left it open to a con-
siderable range of interpretation. Schwann says, "The
development of the proposition that there exists one gen-
eral principle for the formation of all organic productions,
and that this principle is the formation of cells as well as
the conclusion which may be drawn from this proposition,
may be comprised under the term cell-theory, using it in
its more extended signification, while, in a more limited

150

The Organism and Its Cells 151

sense, by the theory of cells we understand whatever may
be inferred from this proposition with respect to the powers
from which these phenomena result." ^

Two meanings, a broader and a narrower, are thus ex-
pressly indicated ; and the permissive phrase "whatever may
be inferred" attached to the more restricted one, points a
way to diversification of interpreting it that was sure to be
followed.

In view of the comprehensiveness of the theory as thus
initially conceived, it is surprising to find Virchow, one of the
earliest and most distinguished promoters of it, speaking
of it as pertaining to the mode of origin of cells. "This
description of the first development of cells out of free
blastema, according to which the nucleus was regarded as
preceding the formation of the cell, and playing the part of
a real cell- former (cytoblast), is the one which is usually
conciseU' designated by the name cell-theory (more ac-
curately theory of free-cell-formation)." ^

O. Hertwig's statement of the theory is as follows : "Plants
and animals, so dissimilar in external appearance, agree in
the foundation of their anatomical structure ; for both are
composed of similar elementary units mostly visible by the
aid of the microscope onl3^ According to an old theory,
now abandoned, these units are called cells, so that the doc-
trine that animals and plants consist in a similar way of
such smallest particles is designated the cell-theory." ^

But Hertwig's treatment of the cell in his earlier volume
Die Zelle, and in his later more comprehensive work,
Allgemeine BioJogie, (4th ed.), surely adds much to the
theor}' that is not hinted at in this brief definition.

The characterization of the theory by E. B. Wilson more
adequately expresses its scope as practically understood and
used by many recent biologists, including Hertwig himself.
"In its broader outlines," writes Wilson, "the nature of this
organization is now accurately determined; and the *cell-

152 The Unity of the Organism

theory,' by which it is formulated, is, therefore, no longer
of an inferential or hypothetical character, but a generalized
statement of observed fact which may be outhned as fol-
lows": — [only the baldest essentials of the outline are here
given]. (1) "In all higher forms of life, whether plants or
animals, the body may be resolved into a vast host of minute
structural units known as cells, out of which, directly or
indirectly, every part is built." (2) "Essentially the cell is a
minute mass of protoplasm," this substance being "uni-
versally recognized as the immediate substratum of all vital
activity." (3) All the cells of each individual organism are
descended by cell division from preceding cells and finally
from one single cell, the fertilized egg-cell. (4) This fer-
tilized egg-cell, which is the beginning of each individual
organism, is produced by the fusion of two cells one of
which comes from the mother, the other from the father
of the individual in question, so that "the ultimate prob-
lems of sex, fertilization, inheritance, and development are
shown to be cell-problems.^^ *

The tout ensemble of meaning and of importance of the
theory for Wilson are forced home in the very first sentence
of his excellent book : "During the half-century that has
elapsed since the enunciation of the cell-theory by Schleiden
and Schwann, in 1838-39, it has become ever more clearl}'^
apparent that the key to all ultimate biological problems
must, in last analysis, be sought in the cell." ^

A concise formulation of the theory with the expansive
meaning given it by Wilson is furnished by Locy in Biology
and its Makers. "A statement of the cell-theory at the
present time, then, must include these four conceptions:
the cell as a unit of structure, the cell as a unit of physio-
logical activity, the cell as embracing all hereditary quali-
ties within its substance, and the cell in the historical de-
velopment of the organism." ^

This expanded form of the theory of cells, held implicitly

The Organism and Its Cells 153

rather than explicitly, has brought it to pass that many
biologists seem to do most of their scientific thinking in
terms of cells. The multiform activities of "cell-life," as
a common expression has it, appear to be the final thought-
goal of such biologists. But the theory is not by any means
allowed so broad a scope by all biologists. This finds illus-
tration in the article on the theory furnished to the Dic-
tionary of Philosophy and Psychology by C. Lloyd Morgan
and E. S. Goodrich. As understood by these authorities,
the theory is, "The doctrine tliat all organisms are composed
either of individual cells (unicellular organisms) or of a
compound aggregate of cells (the higher plants and animals)
with certain cell-products ; and that every cell, no matter
how differentiated in structure or function, is derived from
a preceding cell." ^

A few good authorities, for example, Driesch, even go so
far in restricting the cell-theory to this aspect of it, and in
standing so confidently on its factual nature as to deny
that there really is now a cell-theory at all. The cellular
composition of all organisms (the unicellulars of course
excepted) is, he says, "a simple fact of observation, and I
therefore cannot agree with the common habit of giving to
this plain fact the title of cell-theory. There is nothing
theoretical in it." ^ The examination of definitions has
gone far enough to bring out several points of prime moment
for our enterprise : The cell-theory has been in the past,
and still is, understood quite differently by different biolo-
gists. In the narrower signification given it by such au-
thorities as Morgan and Goodrich, it is held to the strict
bounds of a generalization of observations on the minuter
make-up of both adult and all developmental stages of plants
and animals. Such observations, vast in range and num-
ber, have thus far found no exception to the rule that each
plant and animal body can be resolved into very small units
and products thereof, all the units in each organism being

154 The Unity of the Organism

derived by division from preceding units. These units have
so much in common both structurally and functionally that
the same name may be applied to them all. The name fixed
upon, though a bad misfit because of serious errors of obser-
vation and interpretation on the part of several early inves-
tigators, is cell.

When held down to these narrower limits, the theory
contains no express reference to heredity ; it makes no claim
to "embracing all the hereditary qualities in its substance."
Still less does it contain even by implication the notion
that the "key to all ultimate biological problems must, in
last analysis, be sought in the cell."

(c) Statement of Theory Justified by Present State of

Knowledge

I may now state categorically my view of the cell-
theory : If accepted in the broad signification given it by Wil-
son and many others, it must be recognized as consisting of
two very distinct parts. First, there is the part which ex-
presses in the generalization, no longer questioned by any
one, the cellular constitution of all organisms and the origin
of individual cells. And second, there is the vaguely hypo-
thetical part about the cells "embracing in their substance
all hereditary qualities," and for this and other reasons be-
ing the "ke}^ of all ultimate biological problems." If our dis-
cussion of "The organism and its cells" accomplishes its
aims, it will remove the vagueness of this second part of
the cell-theory, and in doing so, while questioning in no
manner any established truth which it contains, will reveal
the inadequacy of some of its central conceptions.

"The whole of an organism is as essential to the inter-
pretation of its parts as the parts are to the interpretation
of the whole." So runs the first of our fundamental prop-
ositions. Let us substitute "cells" for "parts" in this and
examine it. The organism is as essential to the interpre-

21ie Organism and Its Cells 155

tation of its cells, as the cells are to the interpretation of
the organism. A brief excursion into the liistory of the
cell-theory is essential to the discussion.

It is well known that the early workmen on the cell-
theory had quite erroneous notions of the nature of cells.
The error has, unfortunately, left its conspicuous and in-
eradicable mark on biology in the term cell. This name
was chosen from the circumstance that the first studies were
made on grown plants where the cell-wall is the most easily
observable part of the cell, so that the ctlls frequently ap-
pear like vesicles either quite empty or containing a clear
fluid or semi-fluid. Cells were closed chambers the walls of
which were the main thing, according to tliese pioneering
views. For a long time the nature, structural and func-
tional, of the contents of these chambers played only a
subordinate part. Gradually, however, from widely scat-
tered observations, partly on the simplest unicellular or-
ganisms, partly on the contents of certain simple plant cells,
and partly on the tissues of higher animals, it dawned upon
biologists that the material within the cell-wall is the main
thing, and that this material is much the same in all cells,
whether plant or animal, of low or high degree. The pro-
toplasm of Purkinje and Von Mohl, the sarcode of Dujardin,
the "cell sap" of Corti and Treviranus, and the "plant
nmcilage" of Schleiden, were all brought together because
of their close resemblance and designated by a single name.
On account of the seeming simplicity of this material and
tlie undoubted dependence of life phenomena upon it, pro-
toplasm is the designation now almost universally applied
to it. To Max Schultze, writing in 1861, belongs the credit
more than to any other one man, of comprehending the
nature of cells as we now understand them, and the terminol-
ogy in which Oscar Hertwig expresses Schultze's achieve- ■
ment is of prime significance. Although Schultze retained
the name cell, naturalized in anatomy by Schleiden and

156 The Unity of the Organism

Schwann, he "defines it," Hertwig says, "as a bit of proto-
plasm endowed with life, in which lies a nucleus." '"^

Almost simultaneously with this insight by Schultze, Carl
Briicke, contemplating cells from the standpoint of their
complex structure as well as from that of their ensemble of
life activities, advanced to the conception of the cell as an
organism^.

The language in which Briicke expresses himself on this
point is of sufficient interest to warrant quoting: "We
must ascribe to the living cell, in addition to the molecular
structure of the organic compounds which it contains, still
another and a differently constituted structure, and it is
this which we designate as organization.^^ ^^ And in another
connection he introduces the phrase, now firmly established
in biology, elementary organism, as a designation for the
cell.

One of the securest aspects of the cell-theory was reached
only when the conception organism was applied to the cell.
Both historically and logically, the organism is made to do
duty in interj^retvtig tlie cell. Whatever validity the con-
ception cell has in the modern cell-theory, is due in large
measure to whatever validity the conception organism has.
But the conception organism was well established in biology
long before the conception cell was; hence the justification
of the statement that historically the organism interprets
the cell. Organism as an idea is prior and contributary to
cell as an idea. That logically also the cell is partly in-
terpreted by the organism is seen in the fact that observers
agree in ascribing to the cell the most distinctive attributes
of the organism : namely those of metabolism, reproduction,
response to stimuli, etc.

Our birds-eye view of the cell-theory enabled us to see
that if it be held in the broad sense in which it is con-
ceived by many but not by all biologists, it consists of two
parts: — one a firmly established generalization of observed

The Organisvi and Its Cells 157

facts, the other a vaguely stated hypothesis. We further
saw tliat the secure generalization has two quite distinct
parts, the one stating that higher organisms arc made up
of cells, the other stating certain cardinal facts about
the cell itself. But later examination fixed attention on the
fact that the theory as now lield regards the cell itself as an
organism. In other words, the two essential components
of that part of the theory which is solidly grounded interpret
each other : By showing how the organism is made up, the
cells interpret the organism ; and by showing what the cell
is in its fundamental attributes, the organism interprets the
cell. The cell is a "key" to the nature of the organism, but
not so in "last analysis" for, at least in equal measure, is
the organism a "key" to the cell. Or, if the idea of heredity
be introduced into the cell-theory, not more than half the
truth is contained in the statement that the cell "embraces
all hereditary qualities in its substance," for we have seen
that one of the corner-stones of the modern conception of
the cell, as laid down by Schultze and Briicke, is that
the attributes of the organism belong to it also, not indeed
merely hidden "in its substance," but patent and observable.
If we restrict attention to the germ-cells and apply to
them the idea of hereditary qualities embraced in their sub-
stance, we are still bound, as consistent evolutionists, to ask
how the germ-cells came by these qualities. No answer is
forthcoming to this inquiry which does not essentially involve
the fact that the germ-cells received the qualities from the
])arent organisms. The interpretative relation between the
organism and its cells is one of strict reciprocality whether
the germ-cells or soma-cells be regarded, even in the broad
general terms of the cell-theory. The problem of the or-
ganism and its cells is the general form of the old special
problem of the hen and the egg. Which came first, runs the
familiar conundrum, the hen or the egg? Expressed in
scjeptjfic terms, the questiop is, which interprets or explains

158 The Unity of the Organism

the other, tlic parent organism or the germ-cells? If the
cell-theory be taken in the broad sense above considered,
the aspect of it which we are holding to be erroneously
hypothetical, would answer that the germ-cells interpret the
parents. According to our standpoint, on the other hand,
this hypothesis is inadequate in that it tells at least no more
than half the truth. The parents interpret the germ-cells
quite as truly as the germ-cells interpret the parents. They
follow each other in a casually related, regularly alternating
series; and biology has no inductive ground for supposing
that either term came first in any ultimate sense.

Certai/n Inadequacies of the Cell-Theory

Having now seen that, in the general development and
formulation of the cell-theory, it is literally true that the
organism has interpreted the cell as much as the cell has
interpreted the organism, we must see something of how
this works out in detail.

The impossibility of fully explaining an organism in terms
of its constituent cells seems to have been felt earlier and
more poignantly by students of the normal development
of individuals than by any other class of biologists. De
Bary's epigrammatic statement, already quoted, "The plant
forms cells; the cell does not form plants (Die Pflanze bildet
Zellen, nicht die Zelle hildet- Pflanzen)^^ was induced primar-
ily by observations of his own and others on developing
plants. Here it is easily demonstrable that the form of
the growing tip is often assumed before the mass divides
up into cells. In other words, the- formation of cells is
certainly in these cases a secondary even though an essential
phenomenon.^ ^

(a) As Tested by Embryonic Development

On the side of animal development, C\ O. Whitman was
the first to produce arguments, both comprclicnsive and ir-

The Organism and Its Cells 159

refutable, against the doctrine of cell hegemony, though Carl
Rauber, Adam Sedgwick, (). Hertwig and a few others had
already become more or less positive dissenters from the
prevailing view. Whitman's studies on the initial embryonal
stages of bony fishes appears to have strongly impressed
upon him the subordination of the cells to the general needs
of the developing fish. "That the forms assumed by the
embryo in successive stages are not dependent on cell-division,
may be demonstrated in almost any ogg. Watch the ex-
pansion of the blastoderm in the pelagic teleost egg^ the
formation of the germ-ring, and especially the axial con-
centration of material, which is so beautifully illustrated in
these eggs. Such developmental processes are, if I mistake
not, clearly indicative of some sort of organization." ^^ And
approaching the problem from a slightly different angle,
he says : "May we not go further, and say that an organism
is an organism from the egg onward, quite independently
of the number of cells present? In that case, continuity of
organization would be the essential thing, while division into
cell-territories might be a matter of quite secondary im-
portance." ^^

It was the domination of cell division by forces other than
those belonging to the cells taken independently that especi-
ally held his interest. "The more carefully we compare the
cleavage in different eggs, the more clear it becomes that the
test of organization in the egg does not lie in its mode of
cleavage, but in subtile formative processes. The plastic
forces heed no cell-boundaries, but mould the germ-mass re-
gardless of the way it is cut up into cells." ^* And he
clearly saw that to fly from cells to nuclei, there to seek
final explanatory refuge, as Sedgwack particularly had pro-
posed, was no more satisfactory than to stay with the
cells.

"The essence of organization," he says, "can no more
lie in the number of nuclei than in the number of cells. The

160 Tl e Unity of the Organism

structure whicli we see in a cell-mosaic is something super-
added to organization, not itself the foundation of organi-
zation." Then follows this pregnant sentence : "Compara-
tive embryology reminds us at every turn that the organism
doaninates cell formation, using for the same purpose one,
several, or many cells, massing its material and directing
its movements, and shaping its organs, as if cells did not
exist, or as if they existed only in complete subordination to
its will, if I may so speak." ^^ After sketching the rise and
fall of that puzzling structure in many vertebrate embryos
known as Kupfter's vesicle. Whitman writes : "This re-
markable reproduction of a form-phase that is to last only
a few hours and then pass away without leaving a visible
trace of its existence, cannot be explained as due to cell-
formation nor as the result of indiindiuil action or inter-
action on the part of the cells. The embryonic mass acts
rather as a unit^ tending always to assume the form peculiar
to the state of development reached by its essential 'archi-
tectonic elements,' (Briicke), elements that are no less real
because, like the atom and molecule, they are too minute to
be seen by the aid of our present microscopes. That cells
as such do not participate in this formative act, is shown
by the mode of development of the vesicle and by the absence
of cells in its ventral and lateral wall." ^^

We have now examined Whitman's position far enough
for our present point; that, namely, of showing the strength
of his conviction that cells taken individually furnish no
adequate explanation of the normally developing individual
organism. The evidence he presents to this end never has
been nor, I am persuaded, can ever be overpowered. On the
other hand, any one who will study, as Whitman himself
says, "more faithfully the living embryo during its forma-
tion" ^"^ will find abundance of further evidence to the same
effect. So far — and this is a very long way — Whitman was
crystal clear. Further than this he was unable to break away

The Organism and Its Cells 161

from the old elenieiitalist form of reasoning.

Tlie name of E. B. Wilson was coupled with that of Whit-
man in my general introductory remarks on the appearance
in modern biology of the conception of the organism as a
whole. We will now examine in some detail this authority's
views concerning the cell in development. Discussing the so-
called Mosaic theory of development in 1893 Wilson said,
"I will here point out one all-important point which is
definitely established by tlie work of Driesch and other ex-
perimentalists, and which is accepted by all opponents of
the mosaic theory, namely, that the cell cannot be regarded
as an isolated and independent unit. The only unity is that
of the entire organism, and as long as its cells remain in
continuity they are to be regarded not as morphological
individuals, but as specialized centres of action into which
the living body resolves itself, and by means of which the
physiological division of labor is effected." ^^

After referring to Schwann's having drawn "the con-
clusion that the life of the organism is essentially a com-
posite ; that each cell has its independent life ; and that the
whole organism subsists only by means of the reciprocal
action of the single elementary parts," Wilson says : "It is,
however, becoming more and more clearly apparent that this
conception expresses only a part of the truth, and that
Schwann went too far in denying the influence of the or-
ganism upon the local activities of the cells. It would, of
course, be absurd to maintain that the whole can consist
of more than the sum of the parts. Yet, as far as growth
and development are concerned, it has now been clearly
demonstrated that only in a limited sense can the cells be
regarded as co-operating units. They are rather local
centres of a formative power pervading the growing mass
as a whole, and the physiological autonomy of the individual
cell falls into the background. Broadly viewed, therefore,
the life of the multicellular organism is to be conceived as a

162 The Unity of the Organism

whole, and the apparently composite character which it may
exhibit is owing to a secondary distribution of its energies
among local centres of action." ^^

Our only object in this section is to place before the
reader as much as practicable of the views of biologists that
the organism and not the cells of which it is composed is
the main thing in development. It would consequently be
out of place to go into a critical examination of this lan-
guage. It will, however, be permissible by way of intimation
of what will be involved in the discussion, to ask how the view
that "the life of the multicellular organism is to be con-
ceived as a whole," can be made to tally with the view ex-
pressed in the first sentence of The Cell, already quoted,
that "the key to all ultimate biological problems must, in
the last analysis, be sought in the cell." ^

Wilson's authority is deservedly so great in all these
matters that his utterances will be taken as one of the
main centres around which our examination of the cell theory
will hover. On this account, I quote somewhat more at
length than would be essential to show merely his general
position. In the chapter, "Cell-division and Development,"
he writes : "It remains to inquire more critically into the
nature of the correlation between growth and cell-division.
In the growing tissues, the direction of the division-planes
in the individual cells evidently stands in a definite relation
with the axes of growth in the body, as is especially clear
in the case of rapidly elongating structures (apical buds,
teloblasts, and the like), where the division-planes are pre-
dominantly transverse to the axis of elongation. Which of
these is the primary factor, the direction of general growth
or the direction of the division-planes.'^ This question is a
difficult one to answer, for the two phenomena are often too
closely related to be disentangled. As far as the plants are
concerned, however, it has been conclusively shown by Hof-
mcister, De Bary, and Sachs that the growth of the mass

The Organism and Its Cells 163

is the primary f Mctor ; for the characteristic mode of growth
is often shown by the growing mass before it splits up into
cells, and the form of cell-division ada})ts itself to that of
the mass : "Die Pflanze bildet Zellen, nicht die Zelle bildet
Pflanzen.' jNIuch of the recent work in normal and experi-
mental embryology, as well as that on regeneration, indi-
cates tliat the same is true, in princi])le, of animal growth.
. . . Still more recently this view has been almost demon-
strated through some remarkable experiments on regenera-
tion, which show that definitelj^ formed material, in some
cases even the adult tissues, may be d^^'ectly moulded into
new structures." ^^

I go no farther here in the examination of Wilson's biolog-
ical philosophy than to point out that, in spite of his clear
perception, as indicated by these quotations, that the organ-
ism as a whole plays a determining part in the development
of its constituent elements, his latest statements show that he
is succeeding all too well in obeying the ancient injunction:
"Let not thy right hand know what thy left hand doeth."
Presumably his left hand still clings to the "whole mass
as a moulding power of the parts." But his right hand
seems now more confident than ever of finding the "key to
all ultimate biological problems" in the cells, or maybe in
the chromosomes.

In a lecture published in 1913, speaking of the inter-
esting phenomenon of "criss-cross heredity" in the short
and iong-winged flies lately studied by Morgan, where the
sons are like their mothers and the daughters are like their
fathers, Wilson savs: "This case, and many others of similar
type, may be completely explained through our knowledge
of the relation of the chromosomes to sex. . . . All the facts
revealed by experiment are very simply and completely ac-
counted for by the simple assumption that the x-chromosome
is responsible not only for sex, but also for the short-winged
character." ^^ Our critical examination of this whole mat-

164 The Unity of the Organism

ter, when we come to it, will lead us to see that the essence
of Wilson's criticism of Schwann relative to cells, quoted
above, will now have to be applied to himself relative to
chromosomes : "This conception expresses only part of the
truth, and Schwann went too far in denying the influence
of the totality of the organism upon the local activities of
the cells," said Wilson in 1900. Now we shall have to say
that Wilson goes too far in denying, by implication, the
influence of the totality of the organism in determining sex;
for the assumption that the x-chromosome is "responsible
for sex," and that the facts are "simply and completely ac-
counted for" by this assumption surely involves this impli-
cation.

Driesch's views touching the relation of the organism to
its constituent elements generally are very important, and
will have to be considered under several heads. We have
already referred to his proposal to purge the cell- theory of
all that is hypothetical in it. Continuing the previous quota-
tion, we have this : " . . . attempts to conceive the organ-
ism as a mere aggregate of cells have proved to be wrong.
It is the whole that uses the cells, ... or that mav not
use them." ^- His much discussed theory of "equipotential
morphogenic system" had its inception, as is well known, in
his study of the blastomeres in early embryonic development.
At present, I go no further than to point out that while it
seems certain to Driesch that the "organism as a whole"
is essentially implicated in some fashion in producing organic
structure, it also seems certain to him that he knows nothing-
significant about the nature of that implication. He says:
"So all we know about the proper stimuli of restrictions is
far from resting on any valid grounds at all ; let us not
forget that we are here on the uncertain ground of what
may be called the newest and most up-to-date branch of
the physiology of form. No doubt there will be something
discovered some day, and the idea of the 'whole' in organi-

The Organism and Its Cells 1(15

zation will probably play some part in it. But in what man-
ner that will happen we are quite unable to predict." ^^

I conclude this inventory of expressed recognitions by
competent observers that the organism dominates its cells
in embryogenesis, with two modes of formulating this recog-
nition that are specially significant. They are expressions
of the unity or oneness of the individual organism in time;
and of its unity or oneness in space.

E. G. Conklin has expressed the first truth with com-
mendable decisiveness and simplicity: "Furthermore, from
its earliest to its latest stage an individual is one and the
same organism ; the egg of a frog is a frog in an early stage
of development and the characteristics of the adult frog
develo]! out of the egg, but are not transmitted through it
by some 'bearers of heredity.' " ^^ This proposition is so
nearly self-evident that it would not need insisting upon
but for its having been obscured by sophistical discussions
of whether development is "predetermined" or "epigenetic."
Huxley stated it in essence when he declared it to be "certain
that the germ is not merely a body in which life is dormant
or potential, but that it is itself simply a detached portion
of the substance of a pre-existing living body."

Nageli put it in still more concrete temis when he af-
firmed that the hen's egg differs from the frog's egg as
much as the grown-up hen differs from the grown-up frog ;
that the species is no less certainly contained in the egg
than in the adult. However this speculator befogged the
truth with his fanciful idioplasm. The best expression of
tlie spacial unity of the developing organism with which I
am acquainted is that by F. R. Lillie : "The traditional
view, held by many embryologists at the present day, is that
the physiological unity arises in the course of embryonic
development by the secondary adaptation of originally in-
dependent parts to one another. But this explanation has,
in my opinion, become untenable, and nmst be replaced by

166 The Unity of the Organism

tlie view that there are certain properties of the whole, con-
stituting a principle of unity of organization, that are part
of the original inheritance, and tJms continuous through
the cycles of the generations and do not arise anew in
each.'' '"

For the present I do no more than remind the reader that
the itahcs here are Lillie's, not mine ; and that his clear and
empliaticallj expressed conclusion does not rest alone on the
experiments presented in the paper quoted from, but had
been, in essentials, reached by him through earlier studies
on normally developing animals.

Several of the few biologists who have taken a positive
stand against the dogma of the all-sufficiency of the Cell in
biology have deplored the well-nigh universal custom of
early indoctrinating young students with that part of the
cell-theory which I have characterized as vaguely hypothe-
tical. Adam Sedgwick in particular concentrated his fire
on this aspect of the matter. There can be no doubt that
many if not most recent elementary text-books are unwitting
sinners in this. On the outmost threshold of the temple
of biological science, the student is made to feel, by the
priests within, that the head should be bowed, the knee bent
and the voice subdued when certain things, some difficultly
visible, some wholly invisible, things situated deep in the
interiors of the plants and the animals to be studied, are
mentioned. Among these minute objects of adoration, the
Cell holds a commanding place. "Every scientific animal
and plant anatomy must, consequently, take its starting
point in the doctrine of the Cell." ^^* No matter how long
a shelf of elementary text-books on botany and zoology one
examines, he will rarely fail to find something akin to this
explicit statement in R. Hertwig's excellent Lehrhuch der
Zoologie.

According to this the anatomy of Vesalius, Wm. Harvey,
John Hunter and George Cuvier, and others who lived and

The Organism and Its Cells 1G7

wrought before there was any cell-theory, are unscientific.
But not quite all writers of guides for the young see the mat-
ter this way. B. Hatschek may be mentioned as one excep-
tion. In his Lchrbuch he writes: "If therefore we raise the
question why one cell body undergoes this, another that
transformation, we shall indicate as a chief cause the rela-
tion of the cells first of all to their neighbor cells, and then
to the totality of the body." For the moment we will be
satisfied with this recognition that in the relation of the
cells to the totality of the body as well as to one another,
resides a cause of differentiation of the cells in the com-
pleted organism, and will not be querulous over the state-
ment that this relation stands "first of all" as a cause.

I believe enough has now been brought forward on the
pros and cons of the cell-theory of development to establish
two things : Those biologists who by reason of their own
researches, either through unaided observation or through
observation assisted by experiment, are most deserving of
being heard on the subject are persuaded, first, that not-
withstanding the fact that the developing and developed
organism is wholly produced through the multiplication and
differentiation of cells, these cells are not an adequate ex-
planation of embryogeny ; and, second, that the organism
as a totality must enter as an essential element into any
adequate explanation of the phenomenon.

(6) As Tested by Isolated Cells and Tissues

Before Lillie's contention that the traditional explanation
of the developing embryo has "become untenable and must
be replaced by the view that there are certain properties
of the whole, constituting a principle of unity of organiza-
tion, that are part of the original inheritance,^^ can gain
much influence on biological thinking, it will have to be
examined from many directions.

168 The Unity of the Organism

What, on cursory view, looks more like confirmation of
the theory of cells as wholly independent elements whose
cooperation explains the organism, than any facts recently
brought to hght, are some of the results of recent researches
on isolated tissues — "tissue cultures," as they are frequently
called. The German phrase, ueherlehende Gemebe, — sur-
viving tissues — for these is very apt.

Although the work of Alexis Carrel in this realm has at-
tracted much interest and attention even on the part of
the general public, it is recognized by biologists, including
Dr. Carrel, that R. G. Harrison not only initiated the
methods employed, but also reached highly important results
by applying them. The specific purposes and results of
Harrison's researches, and his general attitude to^yard prob-
lems of individual development, are of prime moment for
our discussion. His central aim was to end the perennial
debate over the mode of origin of nerve fibers in vertebrate
embryos, and the persistence, technical skill, and cogency
of reasoning with which he worked at the problem until he
advanced its solution sharply beyond the point reached by
any one else, are admirable.

According to the view attributed to Wilhelm His, the
axis cylinders of the nerve fibers of the central nervous
system are outgrowths of the ganglionic cells, their con-
nection with the end organs being secondary. The other
view, less generally held, originally advanced by the physi-
ologist Victor Hensen, is that the fibers are differentiations
within protoplasmic strands which have connected the cen-
tral and periplieral cells from the very time when the cells
themselves were formed, their character as nerve fibers being
taken on only when, through the activities of the growing
embryo, conducting paths are needed.

Harrison's earlier attempts to terminate the controversy
by transplanting limb-buds, under various conditions, from
one frog tadpole to another, had led him to believe strongly

The Organism and Its Cells 1G9

in the first mentioned view, though the methods of experi-
mentation employed were not such as to make it possible
for him to see the actual outgrowth of the fibers. He there-
fore tried to find a way of keeping sufficiently small isolated
bits of the embryonal neural tube to enable him to observe
the growths under the microscope if they actually occur.

A summary of his results stated in his own words is :
"Pieces of undifferentiated embryonic tissue, when isolated
under aseptic precautions in clotted lymph, will live for
weeks and undergo at least the initial stages of normal his-
tological differentiation : cells from the axial mesoderm
give rise to striated muscle fibers ; epidermal cells form a
cuticular border; typical cliromatophores and a mesenchyme-
like tissue are formed from pieces containing portions of the
neural tube and axial mesoderm ; the walls of the neural
tube and the primordia of the cranial ganglia give rise to
long hyaline filaments closely resembling embryonic nerve
fibers.

"Tissues grown in lymph function characteristically, as
is seen in the movement of cilia and the contraction of muscle
fibers when left in organic continuity with fragments of the
neural tube." . . . "The experiments show that neuroblasts
are competent to form primitive nerve fibers within a foreign
unorganized medium simply by the amoeboid outgrowth of
their protoplasm. By eliminating from the periphery all
formed structures which have heretofore been supposed to
transform themselves into nerve fibers and leaving only
the neuroblasts in the field, it is demonstrated that the lat-
ter are the sole elements essential to the formation of nerves.
The concepts of both Hensen and Held are rendered un-
tenable." -^

Thus a developmental point of capital importance which
had been debated at length and with considerable spirit as
long as investigation was conducted upon the organism in
its entire state, was solved by separating from the rest a few

170 The Unity of the Organism

cells and finding that when thus isolated they, were able to
develop much as they do normally within the organism.
Surely no more conclusive proof that the cells of an organ-
ism have a large measure of independent life could be asked.
Harrison epitomizes this aspect of his results in a very clear-
cut paragraph : "The energy of outgrowth is immanent in
the nerve cell, and the initial direction of outgrowth is
already determined within the cell before the outgrowth
actually begins. The formation of the fiber is therefore an
act of self differentiation within Roux's definition." ^^

Do not such discoveries favor unquestionably the view
that, in Wilson's way of saying it, "the key to all ultimate
biological problems must, in last analysis, be sought in the
cell?" Some authors, as. for example Oppel, answer with a
very positive yes^ but I have found nothing in Harrison's
writings to enable one to be sure what he would do were he
to answer this question by choosing between an unqualified
yes and an unqualified no.

However, discussing the general question of the relative
trustworthiness and value of experimental studies of the
sort devised by him, and those of the sort by which prob-
lems of histogenesis are ordinarily prosecuted, he has ex-
pressed views which bear strongly on the question, and
which we present in his own language:

"Why, then, should we, in morphology, be still so domin-
ated by the conception of the object as it occurs in nature,
the organism as a whole, which to many seems to be a sort
of fetish not to be touched lest it show its displeasure by
leading the offender astray.^ There is no real ground for
maintaining this attitude. On the contrary we should en-
deavor to extend our experimental analysis wherever pos-
sible, recognizing that through stud}^ of the abnormal, which
consists merely of those combinations of conditions and
effects tliat do not ordinarily occur in nature, we have the
means of reaching an understanding of the normal, and that

The Orgnnism and Its Cells 171

it is necessary to investigate the properties of the constit-
uent parts of organisms before we can hope to under-
stand them in their entirety. Because of our limited knowl-
edge, we are for the present setting ourselves an impossible
task if we expect to determine with certainty by means of
a few experiments exactly the combination of factors in-
volved in the normal ontogeny of any particular structure.
In fact we can never 'explain' the processes of normal de-
velopment with more than a certain degree of probability,
until we succeed in synthesizing organisms from simple
known constituents or construct working models that show
all of the essential activities of organisms — achievements
from wliich we still are very far removed. Syntheses may
possibly be made, however, at different stages of the analysis
with components of greater or less complexity. Thus it may
be possible to extend the remarkable experiments of H. V.
Wilson." -'

The manifest worth and practicability of the manipula-
tive methods introduced b}^ Harrison assured their quick
adoption by other workers, and already a considerable litera-
ture has come into being dealing with "surviving tissues."
Owing, it seems, largely to the fact that Dr. Carrel has vig-
orously and skillfully applied the methods in the interest of
surgery, he has attained wider distinction in connection with
the researches than has any one else, tliough several other
biologists and physicians have increased knowledge substan-
tially by the new instrument of discovery.

The remarkable viability of tissues removed from their
native setting in the organism and kept under artificial con-
ditions is well brought out in a recent paper by A. H.
Ebeling. This investigator made cultures of fragments of
the heart of chick embryos seven to eighteen days old, a
few of which lived and flourished nearly a year. "The ex-
periments show," said Ebeling, "that connective tissue can
be kept in a condition of active growth outside of the organ-

172 The Unity of the Organism

ism for more than eleven months, that its mass increases
considerably, and its power of proliferation, after such long
period, is more active than at the beginning of its life in
vitro/' ^^ In one culture, fragments of the heart pulsated
after 104 days. The evidence is now conclusive that various
tissues of numerous animals are able to live and grow and
perform something of their characteristic activities for a
long time after being separated in small fragments from the
organism at various stages of its development.

Another striking attribute proved for the cells of young
embryos is their mobility. Harrison dwells on the cxten-
siveness and significance of this, and all the other investi-
gators are impressed with it. The wandering about and
the putting out of protoplasmic processes by cells of various
sorts, notably by connective tissue and nerve cells, are men-
tioned by all writers. Burrows' account of the behavior
of the growing nerve fibers is particularly full and well
illustrated, and many of the facts are so significant that I
quote at some length from his description : "Growth of
the nerve cells is evident by filaments of various sizes. . . .
The slender filaments are composed of a hyaline homogeneous
protoplasm, while in the coarser bundles the homogeneous
character is altered by the appearance of delicate, longi-
tudinal striations. The latter bundles break up into many
fine filamentous branches. . . . At the end of each of these
growing filaments and branches is the characteristic thick-
ened amoeboid swelling. . . . This is an oval or round swell-
ing of the filament from which protrude many actively mov-
ing delicate pseudopodia. The growth of a fiber consists
in the great prolongation and enlargement of one of these
pseudo])odia with a gradual moving outward of the end
knob along the pseudopod. The growth may be so rapid
that the end knob may entirely disappear, to reappear far-
ther out along the new grown part. . . . During this time
(48 to 72 hours) they may . . . reach a length of from one

The Organism and Its Cells 173

to two niillimetcrs. . . . The activity of such fibers is noted
at the amoeboid end and consists in a constant retraction
and new formation of pseudopodia. All observations on
the movement of the growing fiber suggest an active force
within it causing its extension into the medium." ^^

Describing the activities still farther in connection with
the degeneration of some of the nerves, the author con-
tinues: '^The changes in the nerves are mainly at the end.
Here there is periodic thickening, followed by a slow reduc-
tion in size until the entire nerve has retracted into the
tissue in a manner similar to the retraction of the pseu-
dopodia of an amoeba. These phenomena of extension and
retraction may go on alternately in the same fiber. . . .
The retraction is checked after a time and growth again
proceeds in a different direction for a while when the pro-
cess is again repeated." ^^

This primitive amoeboid activity of the cells is by far
the most common and readily accomplishable. The testi-
mony of all observers is at one on this point. But this
activity is by no means the only kind. Contraction of muscle
fibers was seen by Harrison, as mentioned in the quotation
already given ; a number of other investigators have con-
firmed and extended the observations. Burrows, for instance,
has shown that muscle cells from the embryonic chick heart
may contract rhythmically in cultures. He writes : "The
muscular elements grow much less frequently and cellular
outgrowths from them were observed in only about three
per cent, of the experiments. The outgrowths take place
from the myotomes and the heart, and appear in the form
of short chains of striated cells. The striated cells contract
rhythmically along with the portion of the heart from which
tliey arise." ^^

Holmes has made the suggestive observation that although
completely isolated, partly differentiated muscle cells of a
newt may remain functionally active for eight months.

174 The Unity of the Organism

"they had not changed their form, nor had they under-
gone any marked changes in structure." This result is the
more interesting in that muscle cells of similar sort but
contained in a })iece of larva instead of being isolated, con-
tinued to differentiate.

A number of important questions touching the independ-
ent life of embryonal muscle cells are awaiting; further study,
but enough has been done to leave no doubt that, broadly
speaking, they possess a considerable degree of such inde-
pendence.

Not only are cells able to continue their physical activi-
ties, but in some cases they are also able to go on with
their chemical activities, after being separated from the
organism. The evidence is conclusive, then, that once formed,
a number of kinds of tissue cells may survive for a long
period after removal from the organism and may continue
to perform more or less faithfully their wonted activities.
Can new cells also be produced under the new and unusual
conditions? Undoubtedly. While to a large extent the
changes described by all observers in surviving fragments
are due to the wandering out and wandering about of cells
already in existence, cell multiplication has been clearly
seen by too many good experimenters to leave any doubt
on the main point. The large increase in mass of the frag-
ments described by all those who have 'kept the same cul-
tures alive and active for a long time would be conclusive
even if cell-division itself had not been seen.

Carrel and Burrows were apparently the first to witness
directly cell division. "A culture contains emigrated as well
as proliferated cells. The proliferated elements consist of
connective tissue and epithelial cells, the former predomin-
ating." ^"^ This is explicit though wanting in detail. But
other observers have been sufficiently explicit. As long ago
as 1906, H. Deeljen described with considerable particularity
the division of the polynucleate leucocytes of human blood

The Organism and Its Cells 175

when kept under proper conditions in microscopic prepara-
tions. And more recently Oppel, applying the new methods,
has described, figured, and discussed at length mitotic divi-
sions of cells isolated from various tissues of the cat.

When we pass from the question of the independent life
of individual cells to that of the independence of organs,
or organized groups of cells, the prospect changes consider-
ably. Harrison, in one of his earliest publications, says :
"While the cell aggregates, which make up the different
organs and organ complexes of the embryo do not undergo
normal transformation in form, owing no doubt in part to
the abnormal conditions of mechanical tension . . . the in-
dividual tissue elements do differentiate characteristic-
ally." ^'^ Without raising the question as to how "charac-
teristically" the individual elements can differentiate while
the cell aggregates "do not undergo normal transforma-
tion," the assertion that the aggregates do not transform
into organs is sufficient for the point being made.

Carrel and Burrow^s have described "tubular formations"
in cultures of both the kidney and the thyroid gland of the
chick. The growth of kidney tubules is affirmed with special
particularity. The authors write: "At several points, tubu-
lar formations were observed which extended themselves a
considerable distance toward the middle of the plasma. Their
ends were rounded, their lumina open, and their walls formed
of cells which had the appearance of epithelial cells. These
formations resembled renal tubules." ^^

The production of these structures is surely interesting,
but more interesting is the question raised by the last sen-
tence : are the formations actually renal tubules, or do they
only resemble them? That no organization of cells info
normal organs takes place in these '"'cultures'''' is attested
by all who have pursued these investigations, so the state-
ment by Carrel and Burrows that the formations resemble
kidney tubules is to be taken as literally true, and to be

176 The Uniti/ of the Organism

understood to imply that the resemblance is not sufficiently
close to make them indeed such tubules.

On the matter of organ production by tissues separated
from the body, Burrows has given us a decisive statement.
"Such growing cells," he says, "from an isolated piece of
tissue liave at no time shown evidence of grouping in a form
comparable to organ formation in the body." ^^

Some experimenters appear to have clearly seen the im-
portance of this limitation of power of the tissues, and on
this account have taken rather strong grounds against call-
ing the preparations "cultures." J. Jolly in particular
has his eyes wide open toward the phenomena, though pos-
sibly some details of his criticisms are overwrought. He
says, "In certain tissues m mtro it appears possible for cel-
lular multiplication to continue for some time, that much is
true; but between tliis last effort of certain cells and a
'culture' — a development continued and progressive — there
is a gap, which may be filled up some day. For the present,
it is an abuse of language to attach the name 'cultures' to
the results obtained." ^^ And the author thinks true de-
velopment of kidney tubules is not proved by Carrel and
Burrows.

Denial of development in a strict sense is made also by
A. Dilgcr: "On the basis of this critique and of his own
investigations, the author must emphatically deny that in
the case of cultures of fragments of the mature organs of
warm-blooded animals any genuine growth takes place in
the sense of an organic formation. In this essential the
author would adopt the view of Jolly, that the Carrel-Bur-
rows experiment indeed demonstrates a survival and physio-
logical functioning of tissue fragments, but has nothing to
do with their growth." ^^

It may be un})rofitable to spend time on the question of
what name should be aj^plied to these vmique preparations,
further than to insist that the name settled upon shall not

The Organism and Its Cells 177

give a false impression of their true nature. If they are
to be called "cultures," then tlie word must be understood
to have a somewliat different meaning from what it has
in ordinary biological technology, where the production of
true organisms is always contemplated. Indeed the distinction
is at least partly recognized by Carrel and Burrows, for in
one of their publications they say: "Since the tissues, in
their development, must adapt themselves to the morpholog-
ical plan of the organism, their growth must be constantly
regulated by some iniknown factor. This regulation may be
caused by certain chemical compounds contained in the
blood and the interstitial lymph. . . . Therefore, it may be
assumed tliat the power of growth is kept under constant
restraint, that every organ is compelled to follow the mor-
phological plan of the organism, and normal plasma is far
from being the optimal medium for the culture of normal
cells." 4"^

Now that we are learning so much about the part played
by chemical messengers, or hormones, in normalizing growth
(see Chapter 18, in Part II of this book), the conception
that "every organ is compelled to follow the morphological
plan of the organism" is gaining intelligibility.

This statement goes, by unmistakable inference at least,
to the very heart of the matter. Even were it demonstrated
that embryonal cells and organs are capable of developing
into perfectly normal adult parts when isolated from the
embryos, this would prove that these cells and organs are
capable of independent life in an ontogenic sense only. It
would not prove them so independent in a full sense, that
is, in a phylogenic as well as an ontogenic sense.

The very fact that the adult organs into which they
developed could be pronounced normal would mean that their
development was, in Carrel and Burrows' language, "com-
pelled to follow the morphological plan of the organism."
In other words, the development would be guided by heredity

178

The Unitij of the Organism

just as certainly as though the parts had not been isolated.
And so we are able to see what is implied in Harrison's
remark quoted above, "we can never 'explain' the processes
of normal development with more than a reasonable degree
of probability until we succeed in synthesizing organisms."
If the condition thus placed on explanation of development
is really necessary, such explanation will never be forth-
coming, since to synthesize organisms would be to synthesize
them endowed with their hereditary attributes and powers —
in other words, with their ancestral attributes and powers.
But in order to synthesize them with such attributes and
powers it would be necessary to synthesize not only the
organisms, but also their ancestors — a rather difficult task.

REFERENCE INDEX

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5.

6.

7.

8.

9.
10.
11.
19.
13.
14.
15.
16.
17.
18.
19.
20.

Locy . .
Virchow

249
36

Hertwig, O. ('12) 3

Wilson, E. B. ('00) 3

Wilson, E. B. ('00) 1

Eocy 252

Morgan and Goodrich. , I, 169

Driesch 27

Hertwig, O. ('12) 8

Briicke 386

Wilson, E. B. ('00) 393

Whitman 110

Whitman Ill

Whitman 109

Whitman 119

Whitman 121

Whitman 120

Wilson, E. B. ('93) 8

Wilson, E. B. ('00) 58

Wilson, E. B. ('00) 393

21

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23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.

Wilson, E
Driesch .

Driesch

Conklin ('08)

Lillie, F. R..

Hertwig,

Harrison

Harrison

Harrison

Ebeling

Burrows

Burrows

Burrows

B. ('13)

R. ('95)

('10) ...

('10) ..

('12) ...

('11)

('11)

('10)

Carrel and Burrows ('12)

Harrison ('06)

Carrel and Burrows ('12)
Carrel and Burrows ('12)

Jolly

Dilger

Carrel and Burrows ('11)

821

28
117

90
251

47
841
843
184
273

72

74

2058

416

140

298

78
473
317
562

I

Chapter VII

THE CELL-THKORY NOT SUFFICIENT FOR
EXPLAINING THE ORGANISM

N the preceding chapter the cell- theory was shown to
be inadequate as a complete explanation of the organism
when tested by studies of embryonic development and by
experiments on isolated cells and tissues. We now proceed
to consider other phases of the theory which still further
show its limitations.

More General Iiiadequdcy of the Cell-Tlwory

(rt) As Tested hy the Regeneration and Restitution of

Mutilated Organisms

Few topics of research have a more instructive bearing
on the hypothetical portion of the cell-doctrine than has
that of regeneration, taking the word in its general meaning.
Attention may be called first to the far greater inclination
of investigators to neglect cells as such when studying the
re-development of organisms that have been deprived of
some of their parts than when dealing with their development
from the germ.

Such problems as those of cleavage, of molecular be-
havior, and of cell-lineage, which stand out so conspicuously
in most researches on ordinary embr^^onic development, par-
ticularly those concerning themselves primarily with early
stages, are for the most part conspicuous by their absence
in studies on the rehabilitation of mutilated organisms.

Undoubtedly one reason, perhaps the chief reason, for

179

180 The Unitii of the OrganisTn

this is that regenerative processes so frequently involve con-
siderable masses of more or less differentiated tissues rather
than individual cells. A sort of mass action or mass per-
formance takes place with little or no regard to the indi-
vidualized activities of the constituent clementij, whatever
they may be, cells, nuclei, centrosomes, chromosomes or what
not. The most palpable instances of this mass performance
are afforded by those restorative processes in which cell
division plays no part, or but a subordinate part. These
processes are accomplished by the activity of cells already
in existence, by the re-disposing of old cells, rather than
by the production of new ones. Thus Rand describes how
the "cells of the earthworm epidermis are seen to execute
an extensive movement from their original position to an
adjoining surface not previously occupied by epidermis." ^
This movement, Rand shows, is not a passive one due to
pressure or pull by extraneous forces, but is inherent in tlic
cells themselves, and "must be occasioned by an agency
external to the cell, namely, by some factor of the con-
ditions resulting from the injury." Rand looked carefully
for dividing cells in the region of the wound but could find
no indication whatever of these. To the mode of regenera-
tion, "in which a part is transformed directly into a new
organism, or part of an organism without proliferation at
the cut-surface," Morgan has given the name Trior phallaons,
and sets it over against regeneration accomplished through
proliferation, which he calls epimor pilosis.- All investi-
gators now recognize the importance of this distinction.

While cells occupy only a retired place in much of both
the purely descriptive and the speculative writings on re-
generation, it would be wrong to infer that tlie broader
biological conceptions based on the facts of regeneration
have really ignored the cell-theory to tlie extent that at
first sight seems to be the case. As a matter of fact, it turns
out that in many of the discussions of regeneration which

Cell-Theory not Sufficient for Explaining Organisjn 181

on their face are little concerned about cells, there lies an
abiding faitJi in the cell as the "key to all ultimate biological
problems," those of regeneration with the rest. An illum-
inating instance of this came out some thirty years ago,
before the period in which regeneration was the "firing line"
for elementalist biology. I refer to Vochting's attempt to
explain a great range of phenomena in plants by the polarity
of the plant's cells. This investigator's speculations were
based quite as much on his observations on grafting as on
regeneration, lie having studied this subject along with re-
generation and normal development for the purpose of gain-
ing light on development in general and on still larger
biological questions, rather than for ordinary liorticultural
purposes. In observing the result of grafting pieces of
roots on branches and of branches on roots, of reversing
the ends of grafted pieces, and of manipulating the grafts
in several other ways, he was greatly impressed by the
persistence with which the grafted pieces maintain their
characters. The resemblance in several respects of these
phenomena in organisms to those of the magnet led him
to make the utmost possible of the resemblance.

^Morgan's summary of Vochting's speculation so far as
this concerns the cells may be quoted : "The properties of
the tissue-complex rest, in last analysis, on that of the
cells ; the properties of the whole being only the sum total
of the properties of its elements, so that we may say that
every living cell of the root is polarized, not only longitudi-
nally, but also radially ; each has a different apical and
root pole, a different anterior and posterior pole, and also
right and left polar relations." ^

The conception of polarity in plants and animals, which
has had a conspicuous place in later hypotheses of the pro-
duction and regulation of form, has by no means been re-
stricted to discussions in which cells have occupied the
center of interest ; so this is not the place to present it

18S The Umty of the Organism

in all its aspects. For the setting forth of facts and
opinions drawn from studies on regeneration, to see how
these bear on the cell-doctrine, it is enough to say that
these views of Vochting seem not to have met with much
favor among biologists even as a "working hypothesis."
Morgan has shown conclusively the general objection to
them, and the language in which he expresses himself is
noteworthy : "Exception may be taken, I believe, to parts
of Vochting's conclusions, especially in the light of the re-
cent experiments in grafting in animals. It is by no means
to be granted without further demonstration that the proper-
ties of the whole organism are only the sum-total of the
action of the individual cells. If, as seems to be the case,
the cells are organically united into a whole, the properties
of this whole may be very different from the sum of the
properties of the individual cells, just as the properties of
sugar are entirel^^ different from the sum of the properties
of carbon, hydrogen and oxygen." ^

(/;) As Tested hij the Principle of Aggregation

By the "principle of aggregation" I mean the principle
according to which, though a real unity of the organism
is recognized, that unity is held to be secondary and not
primary. This princi})le would be, as touching the cellular
constitution of the organism, diametrically opposed to such
a principle as that formulated by Lillie and quoted in the
previous chapter, namely that there are properties of the
organism which are "part of tlie original inheritance, and
thus continuous through the cycles of the generations and
do not arise anew in each."

Ap})eal to this principle in behalf of the cell-doctrine seems
to go back to Schwann, but to have received its earliest full
expression by Virchow and Haeckel in the "cell state"
conception. More recently the discovery of that close co-
partnership between organisms of different species known as

Cell-Theory not Sufficient for Kxplaining Organism 183

symbiosis has seemed to some biologists to furnish a type of
secondary association which is both sufficiently unitary and
sufficiently separatist, as regards the ultimate elements, to be
available for the explanation of all biotic organization.

The influence of this aggregative conception of the organ-
ism cannot be said to have been very great, so our examina-
tion of it need not be extensive. We will here consider
only the most plausible form of it, that namely which in-
vokes the principle of symbiosis. S. J. Holmes has worked
out a theory of this type more fully than any one else, so
far as I know ; so his paper, entitled The Problem of Form
Regulation, will serve as the basis of our remarks.

After speaking of the organism as a self-regulating
mechanism in which the whole is kept in functional equilib-
rium by the parts being "held in check" in some way, he
writes : "If we suppose that the various cells constituting
the body have each a different kind of metabolism, and that
the products of each cell are in some way utilized by the
neighboring cells, so that each derives an advantage from
the particular association in which it occurs, we may un-
derstand, in a measure, how this check may be brought
about. This supposed relation is realized in a simple scale
by the cases of s>^mbiosis that occur between plants and
animals and between the algae and fungi of lichens. . . .
There is reason to believe that the same fundamental prin-
ciple which serves to explain the regulation of a simple
symbiotic community of animal and plant cells will apply
to highly developed organisms as well. We may regard the
body of a highly complex organism as a sort of symbiotic
community." '^

Although Holmes nowhere says explicitly that cells are
regarded as the vital units of his hypothetical organism,
yet most of his discussion clearly implies this. Thus, he
first considers the simple case of an organism consisting of
"two kinds of cells" ; then afterwards of one made of a

184 The Unity of the Organism

"number of differentiated cells." From this the vital units
assumed seem undoubtedly to be cells. It is significant,
though, that at times in referring to the "balance," and
"equilibrium," and "interdependence" so manifest in all liv-
ing beings, he speaks of "parts," "elements" and so forth ;
that is, things which might be something other than cells :
"By virtue of this dependence it is, to speak figuratively, to
the interest of each part to play its normal role in the
corporate life." And again, "The supposition that every
higher organism is a s^^mbiotic community on a vast scale
composed of innumerable different elements." ^

Indeed, taking the whole discussion together, it seems as
though the teinn cell as sometimes used does not have the
specific meaning attached to it in modern histology and
cytolog}", but stands in a general way for anything, real
or imaginary, within the organism to which some measure
of independent life is ascribed. Thus, pointing out wherein
his theory differs from Roux's Struggle for Existence
among the Parts of an organism, he says : "The whole
process of development . . . may occur, according to our
theory, without the elimination of vital units of any kind,
whether they be biophors, determinants, or individualities
of a higher order, such as cells or organs. We have con-
ceived the parts of an organism to be engaged in a struggle
for existence, but, as the parts are mutually dependent, the
struggle leads to an adjustment to a norm instead of the
elimination of some parts and the survival of others." ^

What are the "parts" here.'^ Are they biophors, and so
forth? Are some of them individualities of a higher order,
as organs? Are all of them "vital units?" What relation
do they hold to the "cells" talked about and diagrammati-
cally figured, as constituting the hypothetical organism?
Exactly how Holmes would answer these queries can not
be made out from his discussion, yet from our standpoint
they are fundamental questions. But it must be remarked

Cell-Theory not Sufficient -for Explaining Organism 185

that if Holmes uses "cells" in the ordinary sense, his specula-
tion is distinctly a backward step from the conceptions
presented by Roux in his Struggle of the Parts, who, so
far as the constitution of the organism is concerned, frankly
recognizes several orders of parts, and concerns himself very
little or not at all with vital units. For instance, he dis-
cusses the struggle of the Molecules, of the Cells, of the
Tissues, and of the Organs.

It seems worth while to call attention to this because
while professedly adopting Roux's conceptions to a con-
siderable extent. Holmes believes he has improved upon his
forerunner in staking less than the latter does on the
eliminative aspect of the struggle theory. In this I agree
with Holmes, but must at the same time maintain, as above
indicated, that in attempting to conceive the struggle in
the terms of cells, regarding these as vital units in an ulti-
mate sense, he falls considerably behind Roux in speculative
soundness and very far behind him in *the methodological
usefulness of his speculation.

The objection to the aggregative conception of the organ-
ism, no matter under what form it presents itself, is so
conclusive that little time need be taken in presenting it:
There is not an atom of etidence that is really in its favor.
Even the facts which at first sight seem most favorable
to it, namely those of symbiosis on which Holmes chiefly
relies, are found when considered a little more closely, to
oppose it. No symbiotic combination known, even that be-
tween the alga and the fungus to make the lichen, ever
occurs as one organism in the sense that any true organism
is one. The symbiotic, or partnership organism, if organism
it can justly be called at all, never begins its individual life
as a single reproductive cell, either as a spore or as a zygote,
i. e., a fertilized ovum, but each species has to reproduce
itself, just as though the association did not occur. As a
matter of fact, in nearl}'^ all known cases of symbiosis one

186 The Unifij of the Organism

of the members to the partnership actually enters the other
and lives upon it at some stage of the game, so the "living
together*' is really a sort of parasitism. The taxonomic
identitj^ of the "consortia," as the partners are sometimes
called, is lost. Concerning the most famous symbiosis known,
that of the lichens, a class of plants which owes its very
existence as a botanical group to the intimate association
that has been contracted between plants of two other such
groups, fungi and algae, we read, "Strictly speaking, both
fungi and algae should be classified in their respective orders ;
but the lichens exhibit among themselves such an agreement
in their structure and mode of life, and have been so
evolved as consortia, that it is more convenient to treat
them as a separate class. . . . From the s3^mbiosis entered
into by a lichen fungus with an alga, a dual organism re-
sults with a distinctive thallus, of which the form (influenced
by the mode of nutrition of the independently assimilating
alga) differs greatly from that of other non-s3nTibiotic
Eumycetes." ^

As a purely imaginary construction one might, perhaps,
picture an organism produced in this fashion which would
not be "dual," as these authors express it, but monal, that
is, (in organism in the usual zoological and botanical sense.
But since such an organism would be a work of the imagina-
tion, pure and simple, with all observational evidence weigh-
ing against its real existence, this particular form of the ag-
grcgational conception of the organism can not be held to
have any scientific value, especially" if the aggregants or con-
sortia be imagined to be cells.

(c) As tested by the Specificity and Metaplasy of

Differentiated Cells

The question now before us is, how far are cells which are
wholly or largely differentiated into tissues bound, willy nilly,
to continue to be just those tissues, and to produce as they

Cell-Theory not Sufficient for Explaining Organism 187

proliferate, other tissues of exactly the same kind. Nothing
concerning the minute structure of organic heings is better
established than that in general tissue cells are "true to
kind" ; that is, once a muscle or nerve or gland cell, always a
muscle or nerve or gland cell, not only in the particular cell's
own existence but in its progeny also. Clearly this must be
so. Were it not, the organism would really not be an organ-
ism at all; it would be a riot of cells differentiated and un-
differentiated.

So obviously and widely true is this that some biologists
have believed it deserves crystallization into a phrase com-
parable to omne viimm ex livo. Accordingly we have Vir-
chow's omjiis cellula e ccllula transformed by L. Bard into
omnis cellula e cellttZa ejusdem natural. But were this for-
mulation rigidly true, and were the tissue elements absolutely
unmodifiable in their individual lives, the aduTt organism, at
least, would certainly be held in the grip, figuratively speak-
ing, of its cells, and the fact might be taken as evidence of the
weightiest kind in support of the theory that the cells are the
key to all organic phenomena.

^luch truth as there unquestionably is in this aphoristic
statement, researches of later years have produced conclusive
proof that it can stand only after receiving important modi-
fication.

Looking at the problem of the deviation of the cells of an
organism from type in a broad way, though without presum-
ing: to make the classification and discussion exhaustive, we
find that three rather well defined classes of such deviations
have been observed. There are (1) cases in which tissues are
induced to undergo radical and more or less permanent
transformation by coming into close and long-continued
contact wuth new or differently applied influences of the
external world; (2) cases in which the replacement of lost
parts of an organism is effected through either the direct
transformation of tissue of one sort belonging to an intact

188 The Umty of the Organism

part of the organism into other tissues of the newly added
parts, or through the derivation of tissues of the renewed
parts from tissues of another sort in tlie old parts by the
latter's first returning to something like an embryonic con-
dition ; (3) cases of transformation of tissues in certain
pathological growths.

Under the first head one of the oldest and most frequently
cited examples is that of the transformation of the soft
mucosa cells lining the vagina into pavement-like cells, when
inversion of that organ occurs. A particularly clear and
interesting example of cell transformation which may be
properly ranged in the same class has recently been reported
b}' Harms. This investigator transplanted pieces of the
thumb pad of the sexually active male frog {Rana fusca)
from one individual to another individual. After about two
months he found that complete union of the grafted piece
had been effected, and that the epithelial cells of the graft
were in a normal condition. The glands, however, peculiar
to the epidermis of these pads showed signs of retrogres-
sive change. In the course of another month or so the
glands had undergone complete transformation into a solid,
wellnigh structureless mass, and the cells of the epithelium
immediately surrounding them had reformed and rearranged
themselves into well-defined encapsulating layers, constitut-
ing what Harms designates as a "metaplastically stratified
epitlielium." This case appears to be, as the author re-
marks, one which "shows all phases of tissue transformation
in a way not open to objection." Tliis case is considerably
different from those previously cited in that the influences
operative in bringing about the tissue changes are more in-
timately connected with the cliemico-vital processes of the
organism, and are less purely mechanical than in the other
cases. Harms does not neglect this aspect of the matter,
but a consideration of it would be out of place here.

Under the second head, one of the most striking and at

Cell-Theory jiot Sufficient for Explaining Organism 189

tlie same time best authenticated instances of transfonination
of tissues accompanying the rej)laccment of lost parts has
been described by Nusbaum and Oxncr. The results of tlieir
researches significant for our present needs are sunmiarily
stated in the translation which follows: ""From what has
been said above, we see that in the regeneration of the an-
terior part of Linens lacteus, which has been robbed of the
entire old alimentary canal, the formation of new tissues
takes place heterogenetically in the highest measure ; tha^^
is, it proceeds in such a w-ay that the new tissues arise from
an entirely strange old tissue from which they arc never
produced under normal conditions. We saw, that is to say,
that the epithelium of the entire new alimentary tract, a
tissue endodermal j)ar excellence, is formed in regeneration
by wander-cells which arise from tlie parenchyma and con-
nective tissue, therefore from a material originally wholly
mesodermal." ^ The elaborate description and illustration
with which they present their observations leaves little to be
desired for making the case trustworthy, even had it not
been confirmed by other workers. Fortunately, however, C.
Dawydoff, a Russian zoologist, working on the same species
at the same time but wholly independently, reached results
identical in every essential particular.

Dawydoff's categorical statement touching the main point
is as follows : "The newly-arisen alimentary canal of Lin^us
lacteus is formed from mesoderm. It is differentiated from
the parenchyma and the walls of the lateral vessels." ^ A
very brief description of the experiment perfonned by these
investigators will suffice to make the crucial part of the
results clear. The nemertean has a long section of body
in front of the mouth, consequently into which no part of
the intestinal canal extends. From this it follows that if
the animal be cut in tw^o anterior to the mouth, the front
piece will be wholly devoid of digestive organs. Notwithstand-
ing this it was found that these gutless, mouthless pieces

190 The Unity of the Organism

would not only continue to live, but would develop into com-
plete worms, the new alimentary tract being formed, as the
quotations show, from the internal tissues of the severed
piece ; that is, from tissues which in the normal worm have
nothing to do with the digestive organs.

The demonstration of this ability of organisms to press
into service certain of their parts to replace other parts
that have been lost, even though the parts implicated are
normally quite different, structurally, functionally and de-
velopmentally, is undoubtedly one of the most important re-
sults of the researches on animal regeneration that were so
eagerly pursued a few years ago. A goodl}^ number of in-
stances of this in widely separated sections of the animal
kingdom have been established beyond cavil.

Nusbaum has performed the useful office of summarizing
these on the basis of the kinds of tissues involved, as fol-
lows:

"1. Formation of muscle elements from epithelial tissues
of ectodermal orioin.

"'2. Formation of connective tissue elements from epi-
thelial tissue of ectodermal origin.

'"3. Formation of muscle elements from differentiated
parenchyma cells of mesodermal origin (from connective
tissue).

"■i. Formation of nerve elements from differentiated epi-
thelial tissues of mesodermal origin." ^^

Suitunari/ of Examination of Inadequacy of Cell-Theory

We have now passed under review several large and quite
distinct groups of knowledge pertaining to those biotic ob-
jects called cells, all of this knowledge favoring the inter-
pretation of these bodies as differentiated parts or members
of the larg-er bodies to which thcv bcloufr. Thev come into
existence one after another as a consequence of the growth

Cell-Theory not Siijjicicnt for ExplainiiKj Organism 191

and differentiation of tJie (organism, and In sti-ict sul)ordina-
tion to its needs. In a word, we are led to see tliat cells
must be regarded as organs of tlie organism just as muscles
and glands and liearts and eyes and feet are so regarded.
They undoubtedly constitute a class of organs rather sharp-
ly set off" from all other classes, but this should not be
permitted to obscure the equally important fact of their
always presenting those attributes which are most general
to all organs, namely those of origination by the growth
and differentiation of the organism, and of being function-
ally subservient to the organism.

Nor should we, while taking note of the attributes of
cells which range them under the general category organs,
neglect to note also the attributes which make them a class
by themselves within that category, namely their similarity
in foiTn, constitution and size, for the whole organic world,
and of still more importance, their office as the implements
or tools by w^hich tlie organism performs the physical
changes and chemical transformations of the materials it
uses.

Advance Toward the Organismal Standpoint Through Con-
ception of the Cell Reached hy Biochemistry Pursued
in Accordance with the Principles of
Physical Chemistry

This last statement turns us back to the concluding sen-
tences of the chapter on The Organism and Its Chemistry.

Our explorations in that field discovered, it will be re-
called, that biochemistry, prosecuted in accordance with the
principles of ph^^sical chemistry, is being led to conceive
the cell as a "highly diff'erentiated system," or an "organ-
ized laboratory" consisting largely of "colloidal complexes"
which constitute, "as it were, a special aj^paratus for per-
forming dynamic chemical events."

192 The Unity of the Organism

Into the details of the physico-chemical conception of the
cell we do not enter again here. Miserably inadequate as
our presentation of the subject was in the previous chapter,
it must suffice for this discussion.

By way of making the conception still more concrete
and vivid, and of emphasizing its importance from the or-
ganismal standpoint I quote Hopkins a little further: "On
ultimate analysis we can scarcely speak at all of living mat-
ter in the cell ; at any rate, we cannot, Avithout gross mis-
use of terms, speak of the cell life as being associated with
any one particular type of molecule. Its life is the ex-
pression of a particular dynamic equilibrium which obtains
in a pol>'phasic system. Certain of the phases may be sep-
arated, mechanically or otherwise, as when we squeeze out
the cell juices, and find that chemical processes still go on
in them ; but 'life,' as we instinctively define it, is a property
of the cell as a whole, because it depends upon the organi-
sation of processes, upon the equilibrium displayed by the
totality of the coexisting phases." ^^

Let us now bring closely alongside these and the pre-
viously quoted statements about the nature of the cell as
seen b}' physical chemistry, statements about its nature as
seen by natural history, these latter statements having been
examined in the preceding chapter. Take this from E. B.
Wilson, for example : "The real unity is that of the entire
organism and as long as its cells remain in continuity they
are to be regarded not as morphological individuals, but
as specialized centers of action into which the living body
resolves itself and by means of which tlie physiological
division of labor is effected."

And this from Whitman : "Comparative embryology re-
minds us at every turn that the organism dominates cell
formation, using for the same purpose one, several, or many
cells, massing its material and directing its movements, and
shaping its organs, as if the cells did not exist, or as if they

Cell-Theory not Sufficient for Explaining Organism 193

existed only in complete subordination to its will, if one
may so speak."

And this from Lillie : "The traditional view, held by many
embryologists at the present day, is that the physiological
unity arises in the course of embryonic development of the
secondary adaptation of originally independent parts to
one another. But this explanation has, in my opinion, be-
come untenable, and must be replaced by the view that
there are certain properties of the w^hole, constituting a
principle of unity of organization, that are part of the
original inheritance, and thus continuous through the cycles
of the generations and do not arise anew in each."

And finally this statement by Conklin of the often ex-
pressed perception that the germ-cell and the adult organ-
ism which develops from it are one and the same individual:
"Furthermore, from its earliest to its latest stage an indi-
vidual is one and the same organism ; the ^gg of a frog is a
frog in an early stage of development."

Recognizing in these four statements a sort of concen-
trated solution of the evidence of our whole discussion of
the cell-theory, that the cells of multicellular organisms are
really organs of the organisms ; that they are not inde-
pendent, ultimate life units but on the contrary exist be-
cause of and in subordination to the organism, how escape
seeing that in such general physico-chemical presentations
of the nature of living substance as those quoted from Hop-
kins whenever the term cell occurs the term organism really
ought to be used? The compulsion to such substitution is
especially direct and compelling from the perception, as
expressed by Conklin, that a frog, for instance, is one and
the same organism whether in the one-celled stage, that is,
existing as a cell, or in the many-celled stage.

But bringing the language of natural history into juxta-
position with that of biochemistry, as we are here doing,
accomplishes more than merely to reveal the necessity for

194 The Unity of the Organism

»

substituting organism for cell in the statements of biochem-
istry. It reveals important details of the general truth that
the organism and not the cell is what physical chemistry is
in reality carrying biochemistry toward. For instance, com-
pare Hopkins' assertion that it is impossible to attribute
cell life to "any one particular type of molecule" with Lil-
lie's that the traditional view according to which cells are
"originally independent parts" and only secondarily be-
come incorporated into the "physiological unity," must be
replaced by the conception that there are "certain proper-
ties of the whole" which constitute a "principle of unity"
that are part of the "original inheritance" of the organism.
The parity here suggested between the natural historian's
objection to conceiving "life" as a phenomenon of "the
Cell," as though on ultimate analysis there were only one
kind of cell, and the modern biochemist's objection to con-
ceiving "life" as a phenomenon of "one particular type of
molecule" should be examined a bit closer. What Hopkins
has in mind in taking a stand against "a particular type of
molecule" as the explanation of life is the "ultimate physio-
logical unit" theory which has cropped up under so many
nomenclatorial garbs in later years, but has reached its
most plausible form, perhaps, in the biogen conception, ably
defended by Verworn.

To this conception, no matter what guise it assumes,
physical chemistry brings the insurmountable objection, so
far as the living cell is concerned, that "life" in the very
simplest expression of it known to observational science, is
yet a great complex of structures and activities which con-
stitute a system. It is a space-occupying, shape-presenting,
self-equilibrating complex. Its very existence is a phenom-
enon of multiplex dynamic unity, the parts of which though
constituting the whole are yet subordinate to the whole.
Hence the modern biochemist's assertion that we cannot
properly speak of the living molecules in the cell> but must

Cell-Theory not Sufficient for Explaining Orqanism 195

tliink of the life of the cell as a property of the cell as a
whole. And hence, too, the natural historian's perception
that he must, in turn, and by the very same general
principles wjiich ouide the physical chemist, insist that life
is a property of the orf^anism as a whole. In Whitman's
expressive language, the "organism dominates cell forma-
tion," exactly as, by imi)lication, Hopkins' language jus-
tifies us in asserting that the cell dominates the "molecules"
of the living substances of which it is constituted.

Likewise the "morphological \)\di\\ of the organism" men-
tioned by Carrel and Burrows as something to which the
tissues "must adapt themselves in their development" (see
quotation in section on tissue cultures) is really the counter-
part in natural history language of the cell as an "organized
laboratory" in biochemical language. And the "unknown
factor" which Carrel and Burrows assume must be added
to the "morphological plan of the organism" to explain the
compulsory adaptation of the differentiating tissues, is sup-
plied by physical chemistry so far as the cell is concerned,
in the dynamical, the self-equilibrating system of phases
recognized as constituting the cell.

But when the perception is reached, as it is through our
examination, that in reality the term "organism" should
take the place of "cell" in biochemical language, the organ-
ism no longer appears as a morphological entity merely, but
as a dynamical, a physiological entity as well, and the "un-
known factor" is sup])lied in the organism-as-a-whole. Once
such a conception of life becomes as clear as it is inevitable,
a seemingly overwhelming difficulty looms up in the fact
that "the organism" as natural history is compelled to deal
with it is infinite in number, theoretically if not practically.
For nothing is more patent than that individual organisms
are the primary material of natural history, and no gen-
eralization of natural history is better grounded than that
no two individuals are quite alike. From which it results

196 The Unity of the Organism

that no individual can be fully understood, fully interpreted,
without itself being made a subject of investigation. No
generalization about organism ])ropcr can be counted on
to apply fully to all organisms ! It is probable that an
ill-defined sense of this difficulty (that of the unreachable-
ness of the whole of living nature by any recognized uni-
versal principle or law) accounts for the turning back of so
many able biologists after they have gone far on the natural
history road. For example, E. B. Wilson's failure to accept
the consequences of his own conclusion, "the real unity is
that of the entire organism," is very likely explicable in
this way. To one who has been so indoctrinated with the
metaphysics which grows naturally out of modern mathe-
matical physics as to make him accept the pronoun'cement
that there are "only two real things in the universe. Matter
and Force," a course of discovery and reasoning which
makes every individual organism, no matter how small and
insignificant, a "real thing" seems preposterous even though
true. But the fact that the conception as modern biology
reaches it is largely due to physics itself through its influ-
ence upon chemistry and biochemistry, ought to contribute
much to the reconciliation of science generally to the con-
ception.

The full meaning of such an exaltation — for exaltation
it undoubtedly amounts to — of the individual can be com-
passed only by a painstaking examination of very many
biological facts and hypotheses and dogmas, this examina-
tion ranging over the whole vast realm of living nature.
Indeed, the final and most convincing evidence for the essen-
tial truth of the conception will be reached only when man
himself and the highest provinces of his nature have been
brought into the examination. By the mode of treatment
adopted in this work we shall not have sounded the deepest
depth explored in it until the end of the last chapters shall

Cell-Theory not Sufficient for Explaining Organism 197

have been reached, those on The Psychic Integration of the
-Organism.

REFERENCE INDEX

1. Rand 48 7. Strasburger et al 417

2. Morgan, T. H. ('01) 23 8. Nusbaiirn and Oxner ... 303

3. Morgan, T. H. ('01 ) . . . . 177 9. Dawydoff 6

4. Holmes, S. J 278 10. Niisbaiim 16

5. Holmes, S. J 279 11. Hopkins 220

6. Holmes, S. J 304

Chapter VIII
FURTHER EXAMINATION OF THE CELL-THEORY

OO pervasive have been the efforts to interpret organic
^^development in accordance with the cell-theory that to
examine them exhaustively is impossible. All one can do
is to choose some of the most prominent and assume that
if the criticism succeeds with these major efforts it could
succeed with the minor ones.

The Mosaic Theory

Two diametrically opposed interpretations of the early
developmental states of the organism have figured largely
in later biological theorizing. According to the first, the
constituent cells of the earliest cleavage stages hold the re-
lation to one another of the stones in a mosaic work ; ac-
cording to the second, each cell is "totipotent," that is, sup-
posedly capable of producing the entire organism.

What the Mosaic Theory Is

What the phrase "mosaic work" means when applied to
an embiryo may be stated in the words of Roux himself, the
discoverer of the phenomena on which the conception rests.

"Mosaic work" designates those "developmental phenom-
ena through which in many eggs, those of the frog for in-
stance, eacli of the two or four first cleavage cells (or the
complex of descendants of these) develop hy thevuehyes
alone into the corresponding body j^art, for example into

198

Further Examination of the Cell-Theory 199

half embryos and so forth, consequently without the forma-
tive cooperation of other parts, so are fashioned independ-
ently, like the stones of a mosaic picture. This takes place
through the 'self-differentiation' of separate cleavage cells
or later separate organ-foundation or in fact artificially de-
limited parts, and is possible only in 'typical' development
since 'atypical' development must proceed with far reaching
formative regulation." ^ And along with this definition of
mosaic work the definition of the mosaic theory should be
noticed. "The mosaic theory is the theory which explains
or at least makes intelligible the 'mosaic work.' It rests
upon the assumption of different qualities in the separate
cells (cell body or also cell nucleus) or organ-foundations
etc. capable of 'self-differentiation'."

Obviously, were it generally true that the cells of an or-
ganism are as distinct as the individual stones in a mosaic,
not only as to their form and structure, but also as to their
activities, including their powers of differentiation, this fact
would go far toward a demonstration that cells really are
the "key to all ultimate biological problems" and the central
thesis of biological elementalism, namely, that the final ex-
planation of all organic phenomena lies in the elements con-
stituting organic bodies, would have found an almost im-
pregnable stronghold. On this account the mosaic theory
has been far more eagerly defended and combatted than its
merits as a strict scientific hypothesis warrant. For this
reason too, it will be profitable for us to devote somewhat
more attention to it than we could otherwise afford.

The central facts on which the mosaic theory rests are
familiar to all students of embryology. Roux killed one of
the two cells of frog eggs when they were in the two-cell
stage of development, by pricking it with a heated needle.
In some cases the other cell remaining uninjured developed
into a half-embryo of somewhat such character as one would
get were he to split a nonnally developed embryo lengthwise

SOO The Unity of the Organism

in the dorso-ventral plane of the body. He then killed three
of the four cells of embryos in the four-celled stage, and in
a few instances got something from the remaining cell quite
like a quarter embryo. On these observations Roux based
the somewhat bold hypothesis that "the development of the
frog's gastrula and of the embryo immediately following the
gastrula-stage is, after the second cleavage-period, a mosaic
work of at least four vertical self-developing (or differen-
tiating) parts." To this, however, was added the shelter-
ing statement, "how far this mosaic work is changed by a
change in position of material in the later development, can-
not be determined."

So striking a series of experiments and so far-reaching
an hypothesis were naturally not permitted to stand long
without re-examination. O. Hertwig was the first to try the
experiment again. His results were quite different from
Roux's. He got no hemi-embryos at all, but on the contrary
a number of whole embryos, more or less badly deformed in
various ways. It should be borne in mind that Roux's
method of killing the cells did not remove the injured cells.
These remained in full or slightly diminished mass, but
wholly inert, as originally supposed, when the operation was
entirely successful. Hertwig, on the contrary, believed that
usually the life of the pierced cells was not entirely de-
stroyed, but that whether quite dead or not, they exerted
an important influence on the developing part, and he
hazarded the opinion that could one of the two cells be
entirely removed, the other would produce a complete em-
bryo though of reduced size.

After much discussion between Roux and Hertwig and
others who came into the field, it was shown by Morgan that
"when the black pole of the uninjured blastomere remained
up, the blastomere developed in all cases observed into a
half -embryo. Conversely, those eggs in which the white pole
was turned upward, formed, in most cases, whole embryos

Further Examination of the Cell-Theory 201

of half-size.^^ It thus seems that the mosaic hypothesis for
the frog is partly true. Under some circumstances tlie
cells seem more or less like the stones in a mosaic, under
other circumstances however they do not. Later work, par-
ticularly by Roux, Curt Ziegler, Morgan and Ellen Torelle,
has in general confirmed this much modified form of the
hypothesis in the case of the frog. It has at the same time
shown how much more complicated the whole matter is than
Roux's original simple statement would lead one to suppose.
But the frog is not the only animal in which the cells of
the early embryo present something of the mosaic character.
C. Chun discovered that one of the cells of the two-celled
stage of a Ctenophore would develop as a half-embryo if
isolated from its mate. Driesch and Morgan confirmed this
discovery in general, but pointed out certain details of
structure of the resulting organisms which make the latter
depart quite fundamentally from half-organisms in a strict
sense. For instance, a true ectoderm covered over the side
that would be the cut surface were two half-animals to be
produced by halving a whole one with a knife. Further,
some of the internal organs, notably the endodermal pockets,
were not merely what they would be in a half-animal, but
were as much like those of a whole animal. The normal
animal has four, so a typical half-animal would have two,
but the half-animals produced from isolated blastomeres
had three. Several later investigations on ctenophore eggs
have been carried out, the upshot of all being that with
very decided reservations the cells of the young embryos
of these animals may be looked upon as the "stones in a
mosaic work." A few other kinds of animals, for example
the mollusc llyanassa ohsoleta show something of the same
sort of developmental capacity.'*^

SOS The Unity of the Organism.

A Modicum of Truth in the Mosaic Theory

It is, then, fully established that in some animals the
cells of the early embryos are so specified or individualized
that each develops to a considerable extent in its own way,
that is, more or less independently of its neighbor cells,
and hence may be crudely compared to the stones in a
mosaic work — crudely, we must insist, since stones as mem-
bers of a mosaic work do not develop at all.

The Theory of Totipotence

This theory is the other side of the shield, the side which
looks as though the cells of the early embryo are "totipo-
tent," that is, as though each cell were able to produce the
whole organism instead of only a pre-ordained portion of it.
Chieftainship, both experimental and speculative, in this
theory of developing embryos is universally accorded to
Hans Driesch. The discoveries by him which had such per-
vasive influence on biological thinking for more than two
decades were first published in 1891. His recent popular
account of his work in The Science and Philosophy of the
Organism, will best serve our present need.

Experimental Facts on Which the Theory Rests

Three years after the publication of Roux's experiments
on the frog's egg, above referred to, Driesch tried essen-
tially the same experiment, but on a different animal and
by a different method. He writes : "It was known from
the cytological researches of the brothers Hertwig and
Boveri that the eggs of the common sea-urchin Echinus
microtuherculatus are able to stand well all sorts of rough
treatment, and that, in particular, when broken into pieces
by shaking, their fragments will survive and continue to

Further Examination of the Cell-Theory S03

segment. ... I shook the germs rather violently during
the two-cell stage, and in several instances I succeeded in
killing one of the blastomercs, while the other one was not
damaged, or in separating the two blastomeres from one
another.

"Let us now follow tlie development of the isolated sur-
viving cell. It went through cleavage just as it would have
done in contact with its sister-cell, and there occurred cleav-
age stages which were just half of the normal ones The
stage, for instance, which corresponded to the normal six-
teen-cell stage . . . showed two micromeres, two macromeres
and four cells of medium size, exactly as if a normal sixteen-
cell stage had been cut in two ; and the form of the whole was
tliat of a hemisj^here. So far there was no divergence from
Roux's results. . . .

"I now noticed on the evening of the first day of the ex-
periment, when the half-germ was composed of about two
hundred elements, that the margin of the hemispherical germ
bent together a little, as if it were about to form a whole
sphere of smaller size, and, indeed the next morning a whole
diminutive blastula was swimming about. I was so much
convinced that I should get Roux's morpliological result in
all its features that, even in spite of this whole blastula, I
now expected that the next morning would reveal to me the
half-organisation of my subject once more. . . . But things
turned out as they were bound to do and not as I had
expected ; there was a typically whole gastrula on my dish
the next morning, differing only by its small size from a
normal one; and this small hut xehole gastrula was followed
by a whole and typical small pluteus-larva.

"That was just the opposite of Roux's result; one of the
first two blastomeres had undergone a half-cleavage as in
liis case, but then it had become a whole organism by a sim-
ple process of rearrangement of its material, without any-
thing that resembled regeneration, in the sense of a comple-

S04 The Unity of the Organism

tion by budding from a wound." ^

Driesch went on with his sea-urchin eggs, as Roux had
with the frog-eggs, to see what cells would do if separated
in the four-cell stage. He found that such cells could also
give rise to whole larvae, Taut of correspondingly diminished
size. So far then, as the sea-urchin is concerned, taking
the facts at their face value, the cells of the very young
embryos were proved to be diametrically the opposite in
their relation to the complex as a whole, from the individual
stones of a mosaic work.

Driesch's methods of treating developing eggs were soon
much resorted to by other investigators, with the general
outcome that numerous animals in widely separated parts
of the animal kingdom were proved to have much the same
developmental ability as the sea-urchin. Wilson found that
the cells of Amphioxus embryos separated in the two- and
four-cell stage would develop from the very he ginning after
isolation like whole eggs of reduced size. It will be recalled
that the sea-urchin cells separated by Driesch developed
at the beginning like half-eggs, and only changed over to
the whole-embryo in the blastula stage. So Wilson's dis-
covery removed Amphioxus still farther from the mosaic
type of development than the sea-urchin had been removed
by Driesch.

The Italian zoologist, Raffaello Zoja, increased knowl-
edge of whole-animal production from a portion of the cells
of the young embryo, by showing that in the hydroid Clytia
ftazidula, not only one of the blastomeres from the two-cell
stage, but one from the four- and eight- and even the six-
teen-cell stage, will develop to complete organisms of dimin-
ished size, the half and the fourth at least, of the whole egg,
being capable of going on with the development until the
adult animal, perfect except as to size, is reached.

In view of the fact that the egg of the frog, a representa-
tive of one of the two main sections of the Amphibia (the

Further Examination of the Cell-Theory 205

anura), served as the starting point for the mosaic theory,
it is particularly interesting to know that the Qgg of Triton,
which represents the other section (the urodela), falls in
with the sea-urchin, Amphioxus, and hydroids, as concerns
the developmental abiHty of tlie separated cells of the two-
cell stage. For this information we are indebted first of all
to Amedeo Herlitzka.

This power of devclo])ing whole animals from portions of
the Qgg has been proved to exist in several other groups,
but enougli detail has now been adduced to show conclu-
sively that the mosaic conception of the organism contains
only a modicum of truth. The observations here briefly set
forth, with others of like import, led Wilson to declare : "In
its original form the mosaic theory has, I believe, received
its deatli-blow." "•

Going still farther, Wilson said in the same discourse,
"I will here point out one all-important point which is defi-
nitely established by the work of Driesch and other experi-
mentalists, and which is accepted by all opponents of the
mosaic theory, namely, that the cell cannot be regarded as
an isolated and independent unit. The only real unity is
that of the entire organism, and as long as its cells remain
in continuity they are to be regarded, not as morphological
individuals, but as specialized centres of action into which
the living body resolves itself, and by means of which the
physiological division of labor is effected." *^

It was these discoveries, antithetic to those which led to
the mosaic theory, that begot in Driesch's mind the concep-
tions of "totipotence," "prospective significance," and the
"harmonic equipotential system."

The formal definition of "totipotence," and of "prospec-
tive significance" may be given here since they concern pri-
marily the cells of the embryo. "Totipotence [is the pos-
session by] a part of the germ as yet not at all or but
slightly 'specified' of a form-producing power similar to that

206 The Unitij of the Organism

of the entire ^gg. It is therefore the power [of such a part]
to develop the entire organism." ^

The meaning of "prosi^ective significance" is that "each
blastomere is a function of its position in the whole." ^

The extreme form of Driesch's view is set forth in his
lucid and often quoted statement that the early cells of
the sea-urchin embryo are "composed of an indifferent ma-
terial, so that they may be thrown about at will, like balls
in a pile, without the least impairment of their power of
development." ^

Balancing the Account Beti&een the Mosaic and Totipotence

Theories

Every one, it would appear, must then admit that, so far
as concerns the part of the cell- theory which would see in
the cell the "key" to all development, these discoveries by
Roux and Driesch neutralize each other. If the cells of
the frog's egg seem in their individual capacities to produce
each its particular part of the organism, those of the sea-
urchin's egg seem, with equal positiveness, to do nothing of
the sort, but on the contrary to be entirely subject to the
needs of the future organism. This, I say, is manifestly the
effect which the original discoveries of Roux and Driesch
have upon each other. But later researches have undoubt-
edly proved that more animals resemble the sea-urchin than
the frog so far as the developmental attribute is concerned.
And the case of Triton, the near relative of the frog should
be particularly remembered. "There is no necessity," says
Herlitzka, "for a predisposition of various parts of the
isolated blastomere (or of the egg) to give origin to de-
terminate organs." ^"

It is quite impossible and unnecessary to follow all the
details of the Rouxian and Drieschian views of the relation
of cells to the organism in development ; but we must notice

Further Examination of the Cell-Theory 207

in a general way the course pursued by Roux relative to the
observations by other biologists and by himself which are
clearly hostile to the mosaic theory. To meet the fact that
under some conditions, even in the frog, not a half-embryo
but a smaller whole embryo develops from the isolated blas-
tomeres, he advanced the notion of "postgeneration." By
this he means the '''supplementary restoration, completely
or incompletely, of a half- or quarter-embryo, or other
'Partial-product' formed in consequence of the destruction
of a part of the cgg.^^ ^^

By coupling this idea with an earlier speculation of his
about the nature of the cell nucleus, he tried to make the
nucleus, instead of the cell, the really responsible element
in the mosaic, at least in those cases in which the whole cell
clearly does not conform to the mosaic conception.

Provision for retreat to the nucleus upon occasion, is
made in his definition of mosaic theory already quoted.^ It
will be recalled that the theory rests on the "assumption
of different qualities in the individual cells (cell body or
cell nucleus, etc.) capable of self differentiation."

Alongside this modification of the original mosaic theory
made by transferring the role of building stones from the
cells to the nuclei, it is instructive to place what is in effect
another modification of an opposite nature invented by G.
Born, in connection with his extensive experiments on graft-
ing together the larvae of various amphibians. Born found
that larvae, not only of different species, but even of diifer-
ent genera and families, could be made to unite to some
extent, the union between the more closely related species
being in general the easiest to accomplish and the most per-
manent, but that in any case each component of the grafted
specimen maintained its specific attributes uninfluenced by
the individual with which it was united. In other words,
animal grafts, so far as these experiments went, follow the
well known rules of plant grafts. The maintenance of iden-

208 The Unity of the Organism

tity of the parts, Born interprets as supporting the mosaic
theory. He says : "From our beginning stage on, the de-
velopment rests essentially upon self-differentiation of the
particular (einzelnen) parts a correlative influence of the
neighborhood (Nachbarshaft) as of the whole cannot be
recognized — neither negative nor positive ; the development
therefore corresponds throughout from our beginning stage
on to the mosaic theory of Roux. The organ-forming germ
regions are parceled out (His)." ^^

That an individual plant or animal made up of parts of
the bodies of two or more other plants or animals grown
together, each constituent maintaining its identity wholly
unmodified by the other parts, has as much resemblance
to a mosaic picture as can well be imagined for any living
being, must be granted. No one should, however, fail to
see the difference between a mosaic of this sort and one of
the sort conceived on the basis of the developmental facts
which were the starting point of Roux's theory. In the first
place "mosaic pictures" of the kind produced by grafting
are genuinely man-made affairs. They never occur in na-
ture. A "mosaic theory" contributes nothing substantial
to their interpretation. Indeed it is difficult to see that
there is room here for any such tlieory. Such a composite
creature undoubtedly resembles somewhat a mosaic picture
and that would seem to be all there is to it. But undoubted-
ly such a creature also differs very much from a mosaic pic-
ture. For one thing, the creatures are alive and mosaic
pictures are not. However, I have no wish to make all that
might be made against the mosaic theory because of its higli
degree of artificiality. The main purpose in bringing for-
ward Born's work and ideas at this point is to direct atten-
tion to his proposal touching what might be called the
scientific aspect of the mosaic theory. The organ-forming
germ areas (organbildende Keimbezirke) of His to which
Born refers, and which unquestionably played a large part

Further Examination of the Cell-Theory 209

ill Roux's original theory, are surely features of the earliest
stages of ontogeny, even of tlie unsegmented ^gg- A passage
from His's Unsere Korperform quoted by Wilson makes this
clear. "The material of the genn is already present in the
flat germ-disc, but is not yet morphologically marked off
and hence not directly recognizable. But by following the
development backwards we may determine the location of
everj' such germ, even at a period when the morphological
differentiation is incomplete or before it occurs ; logically,
indeed, we must extend this process back to the fertilized or
even the unfertilized Qgg. According to this principle, the
germ-disc contains the organ-germs spread out in a flat
plate, and conversely, every point on the germ-disc reap-
pears in a later organ. I call this the principle of organ-
forming germ-regions.^* ^^

But notice now that the organ-forming germ-regions
which were Born's "beginning stages" in his grafted larvae,
were by no means "germ-regions" of the unfertilized or even
fertilized ^gg. They were parts of larvae, i.e., of individual
animals well advanced in development. The pieces in his
mosaic works were not single cells or parts of cells but great
groups of cells, many of them already considerably differ-
entiated from one another, but yet so correlated in their
activities as to enable the grafted parts of the animal to
maintain their specific identity.

A fundamental question, then, raised by the mosaic theory
as formulated to-day is. What is an organ-forming germ
area.? or, more briefly. What is germinal material.'^ Is it
the material of each of the first two, or in some instances
four blastomeres as indicated by the frog's ^gg? Is it
nuclear material as conceived by Roux's modification of his
original theory? Or is it in accordance with Born's idea,
the material of any group of cells no matter how large the
group and how many kinds of cells in it, so long as the
group is able to develop true to the kind of organism to

210 The Unity of the Organism

which it pertains? A critical examination of both the orig-
inal theory and the modifications of it, in the light of the
questions just raised will, I believe, discover that the modi-
fications have in reality destroyed whatever of scientific
value the original theory may have had. There can be no ob-
jection to comparing a living being with a mosaic picture on
the basis of the fact that the former is composed of a great
number and variety of living particles called cells, just as
the mosaic picture is composed of a great number of par-
ticles of stone, but the comparison has at best but little
scientific value, and at worst may be very harmful. The
little scientific value in the comparison is purely subjective
and logical; it concerns the problem of the unity in spite
of the composite qualitj^ of both organism and picture as
objects of perception.

The harmfulncss of which the comparison is capable lies
in the wholly fallacious inferences that may be drawn as
to the mode of origin of the objects compared. The funda-
mental difference between them is that while all the myriad
cells of the organism arise by the repeated auto-division of
one cell, the fertilized ovum, the picture is composed of
pieces of stone cut one by one from rocks which had noth-
ing to do with it, until the pieces were assembled and put in
order to produce it, by men, beings again originally quite in-
dependent of the picture. The undivided egg-cell would then
have to be compared to one such stone block, and a moun-
tain of trouble looms up. In the first place, we know for an
absolute certainty that there is no one block of the pic-
ture from which all the others are produced either by divi-
sion or in any other way ; and in the second place, while
any particular stone block of the picture is nearly or quite
homogeneous so far as the general design of the picture is
concerned, and represents only a small piece in the design,
the undivided egg-cell is itself the whole organism in one
stage of its growth, and contains within itself a consider-

Further Examination of the Cell-Theory 211

able dcsif^-n, or composition ; so much, that is, as is distinc-
tive of the organism in this period of its Hfe.

Nor can Ave let Born's modification of the theory off
without looking at it from another and quite different angle.
The larvae and portions of larvae entering into the graft ,
complexes have, he shows, no correlative influence on one
another, nor is there any influence of the whole on the parts,
and therefore the whole is a mosaic work. But how about
the cellular and tissue elements composing the larvae and
part's of larva? within the complex? May we look upon these
elements also as comparable to stones in a mosaic picture.'^
Is not the fact that the portions of an organism entering
into a graft-complex maintain their specific If not individual
identity, peculiarly strong evidence of correlative influence
of the elements of these portions upon one another.^ The
organized and organizing power of living beings hardly
manifests itself in any way more strikingly than in the
fidelity of grafts to their own kind whether In plants or
animals. But the very essence of organization and organ-
izing power is, as everybody recognizes, correlative in-
fluence or activity. A mosaic picture Is about as near an
antithesis to an organization as can be found. So while
we may willingly grant that an organism made up of parts
of other organisms grafted together resembles to some ex-
tent a mosaic work, we must at the same time recognize
that when looked at in Its real nature it not only does not
support, but really refutes the mosaic theory if that theory
is held to any definite and significant meaning.

The ^^Promorphology"' of Germ-Cells

Although a critical examination of the mosaic theory
found it to be of exceedingly little value at its best, and
downright noxious at its worst, yet we were led to recognize
a measure of foreordlnatlon in each gf the first two cells

212 The Unity of the Organism

of the dividing egg, as in that of the ctcnophore, and under
some circumstances, the frog. Even before division begins,
this intimation of specific structure of the Qgg arrests our
attention. Our standpoint makes organization important
wherever found and of whatever grade.

(«) Facts of Immediate Ohservation on Which the

Conception Rests

The truth is we now know that the undivided egg-cell
stage, in the individual life histories of animals so far as
they have been carefully studied, is already rather highly
organized and to a considerable extent specificaUy organ-
ized with reference to the kind of organism which the egg-
cell represents. Otherwise stated, we know that a thorough-
going account of the life history of any organism must in-
clude its structure and function in and before the undivided
egg-cell stage, as well as its structure and function after
cell-division begins. The science of germ-cell structure and
function previous to the egg-cell division is known to embry-
ologists as promorphology and prophysiology.

The inductive evidence in support of the conceptions of
promorphology and prophysiology is altogether too volu-
minous and complicated to be fully presented in a work
like this ; but the matter is so important that the reader
must not be left in doubt about its conclusiveness.

I call attention first to an aspect of the evidence which
though well known in a general way, is rarely if ever given
the consideration which in my opinion it merits. Reference
is made to the fact that many species of animals, even be-
longing to the same genus in numerous cases, have been
distinguished from one another in all their stages of de-
velopment down to the undivided egg-stage. Investigation
has gone so far in this direction as to make it probable that
ftU species whatever might be thus distinguished were thQ

Further Examination of the Cell-Theory SU^

examinations sufficiently searching.

Tlie most extensive studies in this field have pertained to
groups of animals whose economic or ecological relations
to man are such as to render it important to recognize the
different stages of their lives. Thus in the interest of the
great marine fishing industries of northern Europe, elab-
orate investigations have been undertaken for identifying
the eggs and embryos of numerous species of fishes. Worthy
of special consideration is the partnership work by Fr.
Heincke and E. Ehrenbaum.

After asserting the indispensability of exact specific de-
termination of floating eggs and young fishes as a basis for
any reliable deductions concerning the distribution of the
eggs, the authors say that the possibility of such deter-
mination can be affirmed only conditionally ; and their re-
search had for its object to show in general how far the
identifications can be made, and in particular to ascertain
the extent to which size is distinctive of the different species.
Agreeing with seemingly all zoologists who have attended to
the matter, they say that the oil drops and pigmentation
occurring in so many floating eggs furnish important dis-
tinguishing marks. The time of escape of the embryo from
the Qgg membrane seems also to be distinctive for many
species. Concerning pigment, they affirm that in the ad-
vanced embryonal stages, nearly all fish species can be rec-
ognized with great certainty. Included in the elaborate
study is a "table for determining the floating fish eggs in
the German North Sea." ^^ This is a "key" in the ordinary
sense of the taxonomist and deals with some thirty species
belonging to about twenty genera. The attributes used
chiefly in constructing this key are found in the oil drops,
pigment spots, and size of the eggs.

Mosquitoes are another group of animals which have
drawn considerable attention to their early developmental
stages because of their importance to man; and here again

Si 4 The Vnity of the Orgnmsm

"keys" for the identification of the species are frequently
given for the larv^ae as well as for the adults. I have seen
no work on the subject in which the eggs are treated in this
diagnostic way, but in the ''Report of the Nem Jersey State
Agricultural Eocperiment Station upon the Mosquitoes oc-
curring within the State, their Habits, Life History, etc.""
by Dr. John B. Smith, we read, ''Dr. Dupree tells me that
he has found good characters in both eggs and larvse; but
that they are observable only with the compound micro-
scope." ^^

The truth arrived at in other connections from more
theoretical considerations, that the fertilized agg from which
an individual animal develops is that individual in the one-
cell stage of its life, comes most vividly to view in just these
purely practical studies. Thus in one of the many reports
by Fr. Heincke on the food fishes of the North Sea, the
author says : "The first condition for a right understanding
of the habits and habitats of the food-fishes of the sea, and
in general, of the production of the sea as regards useful
fishes, is an exact knowledge of the occurrence and dis-
tribution of these food-fishes at all the various stages of
their life, from the egg on to the adult mature form.'* ^^

Facts of the sort here set forth have seemed to most biol-
ogists too trivial to deserve consideration in theoretical
discussions, and so far as they have been studied, this lias
been done for the most part either incidentally, or, as in
the cases here adverted to, for practical ends.

(/>) Grounds for Believing Minute Observable Specific
Differences Betxeeen Germ-Cells Important

No matter how minute and superficial may be the at-
tributes which distinguish the egg-cell stages of species,
if these attributes are indubitable and constant they differen-
tiate the species in that stage of the individuals* lives, and

Further ExnmiTiation of the CcU-Theory 215

so from the strictly logical standpoint have the same order
of importance as have smaller discriminative attributes of
any other stage in the individual life ; furthermore, from all
that modern research is bringing to light on the correlation
of attributes, to assume that these minute differences are
really as detached and insignificant as they seem is biologi-
cally quite unwarranted.

To illustrate, what careful biologist would dare affirm,
having due regard for what we now know about the chemical
interaction of the parts of an organism, that the difference
in the size and distribution of the oil globules, let us say,
of the eggs of two species of fish, stops with just that dif-
ference? We are certain, are we not, that the formation of
these globules is connected in some way with the metab-
olism of the ^gg^^ And this means that the truly living
substance and vital processes of the egg are involved. So
it becomes not only possible but highly probable that oil-
drop differences between the eggs are indices of far more
deep-seated differences.

And we must not fail to note that in addition to the
probability of important correlations among these seem-
ingly trivial morphological details through the metabolism
(i.e., through the chemical processes) of the cell, correla-
tions through the physical processes are also to be pre-
sumed in accordance with the conceptions of the cell justi-
fied by physical chemistry. The reader should recall the
quotations from Hopkins on the conception of the cell as a
system in equilibrium. But an additional statement from
the same author will be especially germane at this point.
Speaking of certain metaplasmic constituents of the cell,
Hopkins writes : "These last comprise not only the fat
droplets, glycogen, starch grains, aleurone grains, and the
like, but other deposits not to be demonstrated histologi-
cally. They must be held, too, — a point which has not
been sufficient!}^ insisted upon, to comprise the diverse sub-

216 The Unity of the Organism

stances of smaller molecular weight and greater solubility
which are present in the more fluid phases of the system —
namely, the cell juices. It is important to remember that
change in any one of these constituent phases, including
the metaplasmic phases, must affect the equilibrium of the
whole cell system, and because of this necessary equilibrium-
relation it is difficult to say that any one of the constituent
phases, such as we found permanently present in a living
cell, even a metaplasmic phase, is less essential than any
other to the 'life' of the cell, at least when we view it from
the point of view of metabolism." ^^

Biology will sooner or later surely have to take seriously
in hand this matter of the differences between organic spe-
cies in all the stages of the lives of the individuals repre-
senting those species, the germ-cell stages with the rest.
There is urgent need for the extension of ordinary taxono-
mic investigations to the entire ontogenetic series of organ-
isms, the germ-cell stages included. Such work as that
by Dr. Th. Mortensen on the comparative larval stages of
echinoderms is in this direction and should be far more
widely prosecuted than heretofore.

The classical systematic studies of Gustav Retzius on
the spermatozoa of the animal kingdom are on the whole
the most complete we have in this field; but it must be re-
membered that the differential attributes of species at this
level are likely to have somewhat less correlational sig-
nificance than similar attributes of the eggs, for the reason
that the sperm-cells are more highly differentiated for their
special environment and habits and offices. We may confi-
dently predict extensive researches in the future on the
taxonomy of germ-cells according to the frankl}'^ descrip-
tive standpoint, and on the promorphology of germ-cells
according to the morphological standpoint.

The term promorphology has usually been restricted to
a very different use from that to which I have here put it.

Further Examination of the Cell-Theory 217

namely, to structural features of the ovum which influence
the early stages of cell-division, and the shape, size, struc-
ture and so forth, of the "blastomeres," i.e., the product
of the early egg-cell divisions. These phenomena have been
considered more significant than the differences between
eggs of different species above referred to, and have been
investigated by embryologists rather than by systematists ;
and it is to a large extent on evidence from this source that
the fact that the '''^gg is not one being and the embryo
another and the adult a third, but the Qgg of a human being
is a human being in tlie one-celled stage of development" ^'^
has gained theoretical interest.

Several of the most thoughtful embryologists who have
investigated the earliest stages of numerous animals by the
best modern methods have expressed views more or less
like this, and so are in accord with zoologists who have
been led to the comparative investigation of eggs by prac-
tical considerations.

A quotation from E. B. Wilson will serve well as a start-
ing place for our inquiry as to what promorphology is in
this restricted sense. "It is a remarkable fact," writes
Wilson, "that in a very large number of cases a precise
relation exists between the cleavage products and the adult
parts to which they give rise; and this relation may often
be traced back to the beginning of development, so that
from the first division onward we are able to predict the
exact future of every individual cell. In this regard the
cleavage of the ovum often goes forward with a wonderful
clocklike precision, giving the impression of a strictly or-
dered series in which every division plays a definite role
and has a fixed relation to all that precedes and follows it.
But more than this, the apparent predetennination of the
embryo may often be traced still further back to the regions
of the undivided and even unfertilized ovum." ^^

This preordination of the future animal in the egg before

218 Tlic Unity of the Organism

the beginning of development, strictly understood, about
reaches its zcnitli among the insects. According to W. M.
Wheeler, a Frencli investigator, P. Hallez, states the mat-
ter thus with reference to the cockroach, water-beetle, and
locust : "The egg-cell possesses the same orientation as the
maternal organism that produces it : it has a cephalic pole
and a caudal pole, a right side and a left side, a dorsal
aspect and a ventral aspect ; and these different aspects
of the egg-cell coincide with the corresponding aspects of
the embryo." -" "My obserAations," Wheeler says, "based
on some thirty different insects, accord perfectly with those
of Hallez ;" and lie adds as details that the head end of
the future embryo is usually marked by the micropyle and
that the dorsal and ventral sides are foreshadowed by a
slight flexure of the elongated Qgg in its longitundinal axis,
the concave surface of the oigg corresponding finally to the
dorsal side of the embryo. To understand more specifically
the meaning of this for the point under consideration, it
is necessary to have in mind that such insect eggs as
Wheeler is talking about are largely yolk, so far as bulk
is concerned, and that the very young embryo arising from
division of the protoplasmic part of the Qgg occupies but a
relatively small portion of its whole surface. This small
embryonal patch or blastoderm, after it begins to elongate
and to show traces of the jointed body of the adult insect,
is called the germ-band. "The practical value of Hallez'
law," Wheeler says, "was shown in studying the Xiphidmm
[a locust] ^gg\ all the movements of the germ-band could
be at once referred to the axis of the mature embryo. When
the eggs of other insects are oriented in the same manner,
it is seen that the germ-band invariably arises on the ven-
tral surface of the yolk with its procephaleum directed to-
wards the cephalic, and its tail toward the caudal pole.
No matter what positions it may subsequently assume, it
always returns to its original position before hatching." ^^

Further Examination of the Cell-Theorij 219

This statement about the movements of the germ-band has
reference to the fact that the actively developing part of
the Qgg makes a series of remarkable journeys, as one
might say, within and upon the rest of tlie egg, wliich con-
sists mostly of yolk. In other words the topography and
orientation of the very young insect are so far and so firmly
established before cell multiplication begins that the details
of cell splitting and cell movement and arrangement have
seemingly little or no Influence in determining these rela-
tions, but on the contrary, tliough going on for a time
quite independently of such relations, are finally brought
into conformity with them.

In another group of animals, those to wliich "pill bugs"
and "sow bugs" belong, the eggs, like those of insects, con-
tain a great quantity of yolk but the protoplasm is sharply
separated into two portions, the one superficial and non-
nucleated for a time, the other deeply imbedded in the yolk
and nucleated. Only the centrally situated nucleated por-
tion undergoes division at first. This division is so thor-
oughgoing that the resulting cells, the blastomeres, become
widely separated from one another and scattered through
the yolky part of the ^gg. Later these scattered blasto-
meres migrate into the surface patch of protoplasm and
uniting with it form the blastoderm, the forerunner of the
embryo proper. Investigating this mode of development,
J. P. McMurrich emphasizes the fact that all details
of cell-formation and migration and final arrangement have
reference to structural peculiarities some of which are pres-
ent before cell multiplication begins, while others pertain
only to the later embryo. Both the direction taken by the
spindle of the dividing nuclei, and the aggregation of the
blastomeres in the surface layer of protoplasm are, says
McMurrich, "simply precocious preparations for a differen-
tiation which will later become pronounced ; they refer to the
final form of the embryo, and are instances of Sachs' law

220 The Unity of the Organism

that growth determines division and not division growth." ^^
And the author continues : "Each stage of the development
appears to stand in relation not only to what has preceded
it, but to what will succeed it, and is a link in a chain one
end of which is lost in the obscurity of the past while the
other stretches into the future." And still further: "We
must, I believe, recognize the fact so forcibly discussed by
Dr. Whitman in his lecture on the Inadequacy of the Cell-
Theory of Development and so clearly shown by centro-
lecitlial ova, that in embryological development the differ-
entiation which occurs is a differentiation of the entire or-
ganism and not of the constituent parts or cells of which
it is composed ; physiologicall}^, if not morphologically,
every organism is a syncytium, and future theories of
heredity must take this into consideration."

I will do no more in the way of comment than to call
attention to the fact that the phrase "in embryological
development the differentiation which occurs is a differentia-
tion of the entire organism and not of the constituent parts
or cells," is one Avay of expressing specifically my general
proposition that the organism is an explanation of its parts
or cells.

While the element alist may admit himself compelled to
grant that in animals having eggs of the type dealt with
by Hallez, Wheeler and McMurrich, i.e., eggs of the insect
type, the organism seems as mucli a causal explanation of
the cells as the cells are a causal explanation of the organ-
ism, he will be likely to say tliat eggs of this type are rather
the exception than the rule, taking the whole animal king-
dom into account, and hence that the cases cited do not
justify a sweeping generalization of the sort I am trying
to establish as to the causal power of tlie wliole over the
parts in organic development.

We nmst consequently consider liow tills matter stands
with animals generally. Attention may first be called to

Further Examination of the Cell-Theory 221

Wilson's statciiient already quoted, that "it is a remarkable
fact that in a very large number of cases a precise relation
exists between the cleavage-products and the adult parts
to which they give rise." ^'^ The frog's egg, one of the
earliest and most persistently studied of all eggs, was long
ago discovered to have certain features about it, even before
cell-multiplication set in, that are adumbrative of the struc-
tural relations of tlie future embryo and adult. This was
partly recognized, as Wilson points out, by Karl Ernst Von
Baer, the "father of Embryology" ; and the fact that the
first division plane of this egg corresponds with the plane of
symmetry of the adult frog was discovered more than a
lialf century ago by George Newport.

Another group of animals in which promorphology in
this restricted sense is quite as conspicuous as in the groups
already mentioned is the mollusca. Especially note-
worthy are molluscs of the octopus kind. A research in
this field well known and much admired among embryologists
is by S. Watase on the common squid. Wilson epitomizes
Watase's results touching this matter as follows : "Here
the form of the new-laid egg, before cleavage begins, dis-
tinctly foreshadows that of the embryonic body, and forms
as it were a mould in which the whole development is cast." "^

Watase's own statements are peculiarly instructive since,
as is well known to biologists, he has been an extremist on
what we might call the aggregative theory of the multi-
cellular organism. The fact of a definite organization of
the squid in the one-celled stage of its life he fully recog-
nizes. This organization is, he says, such "that the plane
of the first cleavage furrow may coincide with the plane of
the median axis of the embryo, and the sundering of the
protoplasmic material may take place into right and left,
according to the pre-existing organization of the egg at the
time of cleavage ; and in another case the first cleavage may
roughly correspond to the differentiation of the ectoderm and

S2S The Unity of the Organism

endoderm, also according to the prc-organized constitution
of the protoplasmic materials of the ovum." '^^ How is this
organization of the squid before cell multiplication begins
to be explained in accordance with the conception that
the creature's cells are more fundamental than the creature
itself and are the cause of the creature? Watase's radical
elementalism made it almost obligatory upon him to try to
answer the above question. Something of the difficulty which
the protozoan colony theory of the higher organism has to
face in such cases as this, he seems to have felt, and his way
of meeting it certainly has the merit of being ingenious.
"Even if we admit," he says, "that the unicellular ovum
irrespective of its stages of growth, represents actually the
condition of the ancestral protozoan, a highly differentiated
axial symmetry of a certain metazoan ovum cannot be said
to be an aberrant feature unrepresented in the ancestral
protozoa, so long as the existing forms of the protozoa
often show such a high degree of differentiation in that par-
ticular respect." ^^ As though the high degree of axial
differentiation in some protozoan imagined to be the far-
away ancestor of a squid were an explanation of the axial
differentiation of a squid in its unicellular stage ! It is
hardly possible for speculation to soar on less restrained
wings than this and maintain its claim to being scientific.

So much by way of illustration of animal groups in which
the promorphology consists in a considerable measure of
observable differentiation while the individual animal is yet
in the one-celled state, or, in other words, of animals in
which the individual development has gone some distance in
the Qgg before cell multiplication begins.

(c) Re-flections on a Promorphology of Germ-Cells Beyond

the Limits of Visibility

To make the generalization that the egg is an individual
animal in the one-celled stage of its life, we have now to

Further Exavdnation of the Cell-Thcorij 223

consider those animals in wliicli the egg- does not observably
foreshadoAV the adult by any such axial or other differen-
tiations as do those we have just been considering. Eggs
of this sort, of which tliose of the sea-urchin and amphioxus
are examples, are preeminently the ones called totipotent
by Driesch. Reference to what was set forth in our dis-
cussion of totii:)otence will bring before the reader the fact
that eggs of this kind look to be quite devoid of organiza-
tion forecastive of the adult stage, but yet are so profoundly
stamped in some way with the nature of the species that
not only the undivided egg-cell may develop into an adult
animal, but each of the first two or four or in some cases
even eight blastomeres, may develop into complete animals
if the blastomeres be entirely separated from one another.
All analogy of observable structure and development war-
rants us in believing two things as to the promorphology of
these eggs ; first, that there is some sort of organization
characteristic of the species to which the particular animal
belongs beyond the limits of our present knowledge, and
second, that we have little or no means of predicting what
that organization is. This second point is of much im-
portance from its involvement of embryological specula-
tions on the nature of the germ. The fundamental fact
lost sight of in almost all these speculations is that the
transformations and metamorphoses characteristic of all
organic development are in their very essence unforeseeable.
The history of biology, and especially of comparative em-
bryology, is absolutely conclusive on this point. Over and
over again has it happened that certain developmental
stages in the life cycle of animals have been discovered be-
fore the complete seines of stages were known, and that these
stages were so different from the adult stages that the pre-
dictions made as to the species to which the stages belonged
were entirely wrong. The larva of Balanoglossus is a fa-
mous instance of this in the history of zoology. This larva

224 The Unity of the Organism

resembles the larva of eiichinoderms so much that its dis-
coverer believed it to belong to this group and for a long
time zoologists accepted this view, the truth about it com-
ing out only when the transformation of the larva into the
adult was actually observed. For non-zoological readers
it may be stated that Balanoglossus is a worm-like creature
about as unlike a sea-urchin or a starfish as can be im-
agined. The truth is, it is only by ohservational compara-
tive studies that embryologists are able to predict at all
either the earlier or the later unobserved stages, pertaining
to the developmental career of an animal.

If speculation on the nature of germ-cells had followed
consistently these familia.r and universal principles, the
literature of biology w^ould be unburdened to-day of a vast
load of useless writings. Let any biologist ordinarily prac-
ticed in the methods of embryology ask himself candidly
what he would expect to find in the living fertilized Qgg of a
starfish, for instance, were some manufacturer of micro-
scopes to furnish him with an instrument that would mag-
nify with good definition to a million diameters. Can he
consistently suppose he would see something "carrying" all
the innumerable characters of the adult starfish.'^ Why has
he any more right to suppose he would recognize the char-
acters of the adult in the germ-cell than that he can recog-
nize them in the larva just before metamorphosis, or in any
other stage? Yet what embryologlst has ever talked about
the characters of the adult starfish being "carried" by ele-
ments of the larva? What we are justified in believing on
the basis of the inductive evidence in our possession is that
such a microscope would enable us to recognize many struc-
tural features peculiar to the particular species of starfish
at that particular stage of the individual's life, and that as
development proceeded these egg-stage features or char-
acters would disappear and other characters distinctive
of the embryonal stage, the larval stage, and so on, would

Further Examination of the Cell-Theory 225

appear in regular succession till the adult stage with its
distinctive characters were reached. The great point to be
emphasized is that if we are guided strictly by the observa-
tional and rational methods by which all our knowledge of
organic development has been built up, we see that the ef-
fort to conceive germ-cell promorphology or prophysiology
in terms of representative units succeeds only in so far as
we deceive ourselves into believing that we know what we
do not know, and probably never can know, about the struc-
ture and functions of the germ, and b}^ thus deceiving our-
selves, believe ourselves relieved of the necessity of endeavor-
ing to leani what the actual structure and function of the
germ is.

The metaphysical promorphology and prophysiology of
the germ which, culminating in the "determinants" of Weis-
mann, have befuddled the thinking of many biologists, hold
exactly the same place in the logic of biology that phlogis-
ton held for well nigh a century in the logic of chemistry.
There is surely something in the wood that is a cause of
the flame, so why not say the characters of the flame are
"carried" in the wood by units capable of doing that sort
of thing? And how easy and complete the explanation of
flame would be on that basis ! For minds of such cast as
tliat of Joseph Priestley (about the last ardent defender of
phlogiston) and as those of Weismann and his disciples,
explanations of this sort appear to have great fascination.

It is probably implied, if not definitely contended, by
some present-day geneticists, that the methods of analysis
employed by them, those, namely, of experimental breeding,
the application of Mendelian principles of inheritance, and
the correlation of these with chromosomal studies, are a
refutation of the conceptions above set forth. As a matter
of fact, though, the results of genetical analysis, so far as
they are objective and not purely speculative^ are entirely
confirmatory of the conceptions.

226

The Unity of the Organism

REFERENCE INDEX

Roux
Roux

('12)
('12)

262
142

1.

2.

3.

4.

5.

6.

7.

8.

9.
10.
11.
12, Born 613

Crampton ('96) 1-26

Driesch ('07) 60

Wilson, E. B. ('93) 5

Wilson, E. B. ('93) 8

Roux ('12) 409

Driesch ('94) 12

Driesch ('93) 25

Herlitzka 653

Roux ('12) 311

13. Wilson, E. B. ('00) .... 398

14. Heincke and Ehrenbaum 294

15. Smith 160

16. Heincke 1

17. Hopkins 220

18. Conklin ('15) 102

19. Wilson, E. B. ('00) 378

20. Wheeler, ('93) 67

21. McMurrich ('94) 142

22. Wilson, E. B. ('00) 382

23. Watase 280

Chapter IX
ORGANISISIS CONSISTING OF ONE CELL

A. ADULT FORM AND STllUCTURE

Remarks on the Conception of the Cell as ari Element ary

Organism

WE saw early in the chapter on The Organism and its
Cells that the cell may be advantageously looked upon
as an "elementary organism." The warrantableness of thus
regarding it as set forth by Carl Briicke, who first clearly
reached the perception, should be recalled. This conception is
warranted, Briicke said, by the fact that the cell possesses
an organization of another sort than that pertaining to its
molecular structure. While we may not subscribe to the
implication of his doctrine that the cell has an organization
wholly independent of its molecular structure, yet we must
endorse his conception that it has a structure genuinely
unique as contrasted witli tluit of any non-living body; and
must reckon the perception of this fact as a forward step
of first rate importance in biology.

While we are now to devote a cha})ter to an inquiry into
that peculiar structure of the cell which justifies us in view-
ing it as an elementary organism^ we should recognize that
this discussion falls properly under the general head of
cell-theory taken in the comprehensive sense indicated in
chapter six. As there defined the cell-theory concerns itself
with the structure of the cell as well as with the participa-
tion of cells in the make-up of multicellular organisms. It

227

228 The Unity of the Organism

is only for the didactic purpose of making' this part of the
theory stand out in tlie discussion witli a prominence pro-
portionate to its importance that we give it independent
titular recognition. So our present discussion will intersect
at various points the discussion of the Cell-Theory specifi-
cally. The first intersection is at the place where we brought
out the fact that the conception "organism" is historically
jjrior to "cell," and hence, that in reaching the conception
of the cell as an elementary organism, Briicke and those who
followed him have literally used the organism to explain the
cell. We must now push this idea further in both its logical
and its factual aspects.

First as to the logic of it. When we state that the cell
is an elementary organism, we are speaking in the technical
language of logic, recognizing the cell as a species of the
genus organism. An elementary organism is obviously one
kind of organism, the implication being unescapable that
there are other kinds ; one other kind implied being a not-
elementary, that is, a more complex kind. Organism is a
broader and higher category than elementary organism, an-
other designation for cell. From the natural history stand-
point, then, Haldane's efforts to raise organism to the
dignity of a category in the Kantian sense are superfluous,
this having already been done in the real sense through the
establishment by Briicke and the acceptance by biologists
generally of elementary organism as a defining designation
for cell. This aspect of the logic of the cell-theory is of so
much practical importance that it is desirable to state it
more definitely if possible.

The term cell now universally accepted in biological ter-
minology is a general name applicable to a vast class of
natural objects, the name having become fully established
and defined after years of patient examination and descrip-
tion by many investigators, extending to the whole range
of objects brought under the designation. If one reflects

Organisms Covsistijuj of One Cell 229

on all this he will sec a vast difference of meaning in the
word cell when used in the two assertions: "this object un-
der the microscope is a cell," and such generalizations as
"the key to all ultimate biological problems must be sought
in the cell." In the first case the term performs the com-
paratively simple office of a name for a particular object,
endowed, as one might say, with great ability to make in-
telligible certain phenomena of living beings.

Undoubtedly the name stands for an idea in both cases,
and undoubtedly too, the ideas in the two cases must have
something in common, but equally certain is it that there
are important elements of difference in the two ideas. Of
the elements in common, one, we know very well, relates to
certain structural features, cytoplasm, nucleus, and so on,
experimentally settled upon as essential to any object en-
titled to be called a cell. Another is the conception that all
bodies so entitled arc a kind of organism, i.e., elementary
organism, this conception being based on the observation
that great numbers of cells are, in the language of O. Hert-
wig, "endowed with the attributes of life." Now notice:
by virtue of what is the cell conceived to be the key to all
biological problems.'^ Surely not in the mere presence in it
of bodies that may be called nucleus, cytoplasm, and so
forth, but rather because it is endowed with the attributes
of life, is an organism, even though of an elementary char-
acter. In other words, since typical cells are universally
admitted to be very simple in structure as contrasted with
those bodies to which the term organism was first applied,
and since it is now only one among such bodies, and that an
elementary and simple one, to assert that it is the "key to
all biological phenomena" is a logical contradiction, if by
being the "key" it is implied that the cell is an ultimate ex-
planation of such phenomena, for with such an implication
the assertion is virtually tliat part of a thing is greater than
the whole of it.

2S0 The Unity of the Organism

Comparison of the Structure of Organisms Consisting of a
Single Cell with That of Organisms Consisting

of Many Cells

This chapter will be concerned primarily with the factual
side of the structure of the cell viewed as a species of or-
ganism, and will confine itself to the structure of the cell
in organisms indubitably such in the strict sense, even
though they ordinarily consist of but a single cell.

The narrowing influence of elementalism in biology finds
striking illustration in the application of the cell-doctrine
to unicellular organisms, that is, to the protozoa and the
protophyta, or collectively, the protista. In fact, if one
wishes to bring before him in the clearest possible fashion
the contrast between what a great province of living nature
is when seen as it actually is and when seen through the
medium of elementalist theory let him compare some of the
great modern objective treatises on the protozoa, like Brady's
report on the Foraminifera and Haeckel's on the Radio-
laria, in the Zoology of the Challenger Expedition, or
Haecker's Tiefsee Radiolarien, in Wisse7ischaftliche Ergeh-
nisse der dewtschen Tief see-Expedition, with the statements
one finds in ordinary text books of zoology concerning the
same organisms. Hardl}^ anything could be more mislead-
ing than the almost universal practice in elementary teach-
ing of introducing beginners to the protozoa by showing,
very superficially, an amoeba and emphasizing its simplicity,
and then keeping it in the foreground of the learner's
thought as an exemplification of the doctrine that the pro-
tozoa are "extremely simple" animals, that they are undif-
ferentiated into organs and tissues^ — tliat in fact they are
hardly "true animals" at all. In even so advanced and usu-
ally excellent a work as Lang's Lehrhuch der vergleichenden
Anatomie we are told that the metazoa or "true animals"
{echte Tiere) are "set over against the protozoa or pro-

op.f.

ador.fn.-
o. odor lip...

o.pr-, • I

■circMcs.nng,

bcLl,-,

dxllsk.-.
ant.cilr:--
djtt.

/

FIGURE 1. DTPLODINTU^r ( AFTER SHARP ).

ador.m., adoral membranelles. an., anus. ant. oil. r., anterior ciliary
roots, ant.c.v., anterior contractile vacuole, bd.l., boundary layer
(ectoplasmic). cir.oes.r., circumesophageal ring. caec, caecum,
cut., cuticle, c.v.r., region about contractile vacuole. D., dorsal side
of body, d.disk, dorsal disk. d. furrow, dorsal furrow, d.m.str.,
dorsal motor strand, d.m., dorsal membranelles. ect., ectoplasm,
ent., entoplasm. fd.v., food vacuoles, i.ador.lip, inner adoral lip.
i.d.lip, inner dorsal lij). L., left side of body, l.sk.a., left skeletal
area, mac, macroiuicleus. mic, micronucleus. m.m., motor mass
(motorium). o.odor.fur., outer adoral furrow, o.ador.lip, outer
adoral lip. o.d.fur., outer dorsal furrow, o.d.lip, outer dorsal lip.
oes., oesophagus or cytopharynx. oes.f., oesophageal fibers, oes.-
retr.str., oesophageal retractor strands, op., operculum, op.f., op-
ercular fibers, or., oral opening, mouth, or cytostome. or.cil., oral
cilia, or, disk., oral disk, post.cil.r., posterior ciliary roots, post.c.v.,
posterior contractile vacuole. R., right side of the body, rect., rec-
tum, rect.f., rectal fil)ers. r.sk.a., right skeletal area, sk.lam., skel-
etal laminae, susp.f., suspensory fibers, V, ventral side of body,
v.sk.a., ventral skeletal area, n.m., nuclear membrane.

231

^S2

The Unity of llie Organism

tista," ^ the implication being that the protozoa are not
"time animals." "Organless organisms" is an appellation
one not infrequently finds applied to protozoa.

(«) Comparison of Certain CUiates and Metazoans

By way of introduction to the commentary I wish to make
on this mode of thinking, I ask the reader to compare the
pictures, figures 1 and S, keeping the idea of cell as much

cnt.cav.*

ms

FIGURE 2. HYDRA (aFTER PARKER AND PARKER).

ect., ectoderm. end., endoderm. ent.oav., enteric cavity. mth.,
mouth. hyp., hypostonie. msgl., mesogloea. ntc, nematocysts.
psd., pseiidopods. fl., tiagella. bd., buds, spy., spermary. ovy.,
ovary, ov., ovum.

FIGURE 4

FIGURE 3

FIGURE 4. STEXOSTOMA I.EUCOPS ( AFTER OTt).

c, cilia, c.p., ciliated pits, cu., cuticula.

b., brain, com., brain

commissure, d.o., dish-shaped organs, m., month, ph., pharynx,
ph.c, pharyngeal cells, e.c, epithelial cells, in., intestine, w.v.t.,
water vascular tube, r., rods, p., parenchyme. o.vv., external open-
ing of water vascular tube.

FIGURE 3. STYI.OXYCIIIA MYTILUS (fROM IIARTOG, AFTER LAXg).

a.c, abdominal cirrhi. an., anus discharging the shell of a Diatom,
c.c, caudal cirrhi. c.p., dorsal cirrhi. cv., contractile vacuole, e.,
part of its replenishing canal, f.c, frontal cirrhi. f.v., food vac-
uoles, g., internal undulating membrane. 1., lip. m., mouth or
pharynx, mc, marginal cirrhi. N., X., lobes of meganucleus. n, n,
micronuclei. o., anterior end. per., adoral membranellae. poc,
preoral cilia, p.om., preoral undulating membrane, s.h., sense hairs.

233

SS4 The Unity of the Organism

in the background of consciousness as though he had before
him for comparison a cat and a hen, for instance. Do the
figures give the impression that one presents a very simple
animal wliile the other represents a very complex one?
Which, may well be asked, is the very simple one? Does
one give the impression that it represents an organless ani-
mal, while the other represents an animal with organs?
Does one seem organized while the other is unorganized?
Does one look like a true animal while the other is an un-
true or pseudo-animal? Yet there is now unanimity among
zoologists that the creature represented by figure 1 is a
protozoan, while that represented by figure 2 is a metazoan.
The protozoan sliown is a species of Ciliate which inhabits
the stomach of the ox. Its techincal name is Diplodinium
ecaudatum. The figure is from R. G. Sharp. Figure 2
is of the common fresh water hydra.

Or compare in detail a Stylonychia, a protozoan, with a
Stenostoma, a worm. For the former, the description and
figure of Stylonychia mytilus, figure 3, given by Hartog in
the Cambridge Natural History will serve our purpose well.
A good description of a Stenostoma, figure 4, is furnished
by Ott. A rough and ready way of estimating the degree
of complexity of the two animals is to notice the number of
named parts or organs in the two descriptions, presumably
intended to be about equally thorough.

The activities of these two species have also been well
studied, so they can be compared from this as well as from
the anatomical standpoint. To any one who has watched
both creatures somewhat attentively in their normal lives,
the great animation and diversity of movement of the pro-
tozoan as contrasted with that of the metazoan are striking
enough. Concerning the general character of the movements
of Stylonychia, Hartog writes, "It moves through the water
either by continuous swimming or by jerks, and can either
crawl steadily over the surface of a solid or an air surface

Organisms Consisting of Ojie Cell 235

such as an air bubble, or advance by springs, which recall
those of a hunting spider." - The rapid movement ahead,
running against obstacles, backing off, clianging directions,
and turning around, remind one of the performances of an
ant under similar surroundings, flennings' statement that
they are "usually found running about on the bottom, or
on the surface of objects in the water," ^ is no more a figure
of speech than would be a similar remark about a rabbit.*

FIGURE 5. STYLOXYCHIA MYTILUS ( AFTER Pt'tTER).

With reference to their food habits, Maupas's characteriza-
tion of them as "hunter ciliates," is truly descriptive.

By contrast the movements of Stenostoma are slow and
simple indeed. In it locomotion is accomplished almost en-
tirely by surface cilia, and the well-nigh complete absence
of differentiation among these, as contrasted with the high
degree of differentiation and specialization of the cilia of
Stylonychia, may be taken as a reliable index to the dif-
ference in locomotor activities of the two creatures.

(h) Comparison of a Radiolarian and a Jelly-fish

Carrying the comparison of unicellular, "simple" or "un-
true" animals, with multicellular, "complex," "true," ani-
mals still farther, we will take up a Radiolarian for brief
consideration. Non-technical readers are particularly urged
to look througli tlie volume of 140 quarto plates which il-
lustrate Haeckel's great Challenger Report on tliis group.

* Jenninpjs copies this din gram from Piitter showing a Sfylonyrhia
"creeping- along tlie surface," uiiich sliows well the "belly" and the
"back" sides of the creature and the way in which it uses its cilia as legs.

S36 The Unity of the Organism

Nearly all large libraries have sets of the reports of this
famous exploring expedition.

So astounding was the wealth of life both as to number
of species and elaborateness of structure of the individuals
described and depicted in this report, that many zoologists
who had been properly impressed in their formal training
with the doctrine of the simplicity and minuteness of the
protozoa, were disposed for a long time to accept the re-
port with some "grains of salt" — -to suspect that many of
the specially remarkable species were, partly at least, crea-
tures of the lively imaginations of Haeckel and liis artist.
But later researclies, particularly those of V. Haecker, al-
ready mentioned, on the same animals collected on the cruise
of the Valdkia, of the German Deep-Sea Expedition, have
driven away all shadows of doubt about the essential truth-
fulness of Haeckel's narrations. Indeed, we now know, if
anything, he fell short of full justice to the Radiolarians.

I take this opportunity to remark that one of the serious,
even though perhaps unavoidable, defects of formal instruc-
tion in elementary zoology and botany is the tendency to
fix in the learner's mind the notion that nature is far more
simple than it really is. Of course, the only right antidote
for this falsification is contact with nature itself in its plen-
itude. But since school books and school lessons are main-
ly responsible for the wrong inculcuations, on the principle
that like cures like, books again, though this time of the
elaborate monographic sort, even though no more than
hastily run through, ought to be of considerable use to
young students. Quite as much with the hope of sending
the reader to Haeckel's or one of the other great mono-
graphs on the Radiolaria, as for the purpose of impressing
him with the elaborateness of organization of these animals,
I will refer specifically to a section of Haeckel's Report.

One entire new family discovered in the Challenger's col-
lections, Haeckel named Medusetta. Tlie author gives us

Organisms Consisting of One Cell 237

the reason for the clioice of this name : "Some species are
among" the most admirable forms of Radiolaria, and are simi-
hir to small elegant Medusae. The fonn of the shell ex-
hibits the same varieties as the similar umbrella of the
Medusa. . . . The similarity with the umbrella of a Me-
dusa is so great, tliat In many species the large lower open-
ing on the mouth of the shell Is surrounded by a prominent
ring or diaphragm, comparable to the velum of the Craspe-
dotae or Hydromedusae." * This general resemblance to
certain medusae is made still more striking in such a species
as Gazelletta crytonema bj the phaeodium, a mass of cell-
like pigment-bearing structures "in the lower half of the
shell cavity," ^ sometimes, as in the figure referred to, pro-
truding from the mouth of the shell. Xo one can compare
this figure with those of various medusae which bear gonads
or buds on the manubrium or the subumbrellar region with-
out being struck by the general resemblance between them.
The reader must not infer from this comparison that the
points of resemblance signify anything like close corre-
spondence in structure. As a matter of fact the two ani-
mals are no more alike than a bat and a butterfly. The
sole point of significance, so far at least as this discussion
is concerned, is that judged by the facts of actual structure
and function of the radiolarian and the coelenterate, the
first is hardly if at all more simple than the second — is not
a whit less a true animal.

{c) Comparison of the Shell of a Rhizopod and of a Xaatilus

One more comparison between a "simple" unicellular ani-
mal and a complex multicellular "true" animal is as far as
we can go in the strictly comparative-anatomy part of this
presentation. Take, for example, the shell of Operculina,
the detailed structure of which was worked out by W. B.
Carpenter. Some of the schematic figures in his work are

238 The Unity of the Organism

reproduced in many of the larger textbooks and handbooks,
Biitschli in particular giving specially good figures. The
remarkable resemblance of the shell of this and of allied
genera to the shell of the chambered nautilus has long been
a common subject of remark. According to the prevalent
view, although the variety and complexity of the shells of
great numbers of foraminiferae are universally recognized,
they do not militate against the conception of the animals
as "simple," because they are only secretory structures, or
in many groups only structures built up from foreign sub-
stances. But what right have we, I ask, to assume but slight
protoplasmic differentiation in a creature that can produce
in any way whatever such a system of chambers and septa
and canals and pores, as is presented by the shell of Oper-
cuUna? This query becomes particularly searching when
one considers that each of the various genera and species
has its own type of shell.

In his Monograph of the Foramimfera of the North Paci-
fic Ocean Dr. J. A. Cushman remarks that being single-
celled animals, the structures of the Foraminifcra "do not
need explanation on the basis of organs and tissues." ^ This
naive manner of dodging difficulties is characteristic of ele-
mentalist notions about explanation — the method of making
an implied theoretical definition take the place of searching
examination. The particular difficulty evaded by definition
in this case pertains to the nature of the outer portion of
the protoplasm or sarcodc, which constitutes so large a
fraction of the living body of both the Foraminifcra and the
Rhizopoda. As is well known, the sarcode produces the
shell either by secretion or by the selection and placement
of foreign particles. In many Foraminifcra, as Operculina,
the sarcode extends over the whole exterior of the shell,
thus making the shell an internal structure. The highly
elaborate canal and pore systems above referred to are
passage-ways for the semi-fluid sarcode.

Organisms Consisting of One Cell 239

Intimately connected with the network of sarcode situ-
ated within the substance of the shell and on its surface is
the wonderful pseudopodial system, i.e., the system of in-
numerable filamentous, anastomosing, expanding, withdraw-
ing, and shifting strands of living material. As is well
known, at least for many Rhizopoda, tlie pseudopodial sys-
tem is nutritional in function. First of all, the pseudopo-
dia are prehensile organs and operate in much the same way
and apparently with as great effectiveness as the corre-
sponding organs of higher animals. By means of them the
animals seize their prey consisting of living micro-organisms.
In some species the seizure is accompanied by a stunning
and paralyzing action. After capture the food is, in many
species, transported by the grasping organs through the
mouth of the shell and into the deeper portions of the sar-
code there to undergo digestion. But in some groups the
nutritional office of the pseudopodial system goes much
farther than the mere procurem.ent of food. Digestion, and
so of necessity circulation in part, are performed by the
same system. Calkins ^ mentions the Reticularia particu-
larly as Rhizopods whose digestion is thus performed. What
could be more far-fetched and distracting of attention from
the true nature of the animals, than to call organs that per-
form all these functions "feet," false feet, or feet of any
other kind.^

The locomotor appendages of many animals are brought
into the service of the nutritive function ; and in such ani-
mals, as many of the Crustacea, where this change of func-
tion has gone so far as to divert the organs entirely from
their original office and transforai them both structurally
and functionally into mouthparts, comparative anatomists
never think of still lumping them all together as locom,otor
organs. In no higher animal whatever, so far as I know,
has conversion of the locomotor into nutritional organs
gone so far as to make them not only food-seizing but food-

240 The Unity of the Organism

digesting, as is the case in the Reticularia. Consistency in
descriptive treatment and clear thinking demand that the
sarcode processes of those protozoans in which tlie struc-
tures are wholly or even chiefly nutritive in function should
no longer be called pseudopodia. Some such term as tro-
phorhiza ought to be applied to them, especially where, as
in the Reticularia, they are digestive. Whether or not
the structures "need explanation on the basis of organs and
tissues," they certainly need description and definition that
shall set forth their true nature. Fortunately considerable
study has been devoted to them and the rest of the peri-
pheral sarcode in the Rhizopods, and to the extra-capsular
sarcode of the Radiolaria, so we already know much about
the facts.

Calkins ^ has well summarized the information we possess
concerning the "pseudopodia" of Sarcodina. From this
knowledge we are able to say with the greatest assurance
that these creatures lead their lives — maintain their locus
in space, whether of fixity or movement, respond to external
stimuli, procure, ingest, digest, and assimilate their food,
solid and gaseous, and propagate their kind — no less defi-
nitely and hardly less variedly than the larger multicellular
animals. All these things they do through the instrumen-
tality of definite and definable anatomical elements ; and I
would insist that we can justify the refusal to call these
elements organs and tissues because they occur within the
limits of single cells only by having first so defined organ
and tissue as to exclude from them all organic elements not
composed of cells.

The Unjustifiahle Conception that Unicellular Organisms

Can Hare No Tissues

As a matter of fact this illogical course is exactly the
one that is widely followed. "A tissue is, therefore, a com-

Organisms Consisting of One Cell 241

plex of similarly differentiated cells." ^ This definition of
tissues, occurring In one of the most generally used text-
books of miscroscoj)ical anatomy, turns up in substance
again and again in tlie connnon instructional writings of the
day. "The foundation-stone of the tissue is the cell." ^^
According to this doctrine the cell is the building-stone of
the tissue, so no matter what may be found within the cell,
it cannot be a tissue, l^ndoubtedly this way of treating the
term tissue has been useful, especially didactically, and
undoubtedly too It is on the whole justified so far as multi-
cellular organisms are concerned, though even here 'the
scientifically scrupulous teacher finds himself under the
necessity of doing much uncomfortable wriggling to make
many of the connective tissues fit into it. But when the view
is extended to the whole animal kingdom, to the protozoa
as well as to the metazoa, one sees how inadequate and
cramping such a conception of tissue is.

The fact is, when we consider the real meaning of the
word tissue, and still further, w^ien we consider what the
anatomical parts are to which the early anatomists thought
the term could be appropriately applied, we see that with
the possible exception of some of the connective tissues
of the higher animals, we can hardly- point to a more typical
tissue than that of the network of strands into which the
peripheral sarcode of many of the Rhizopods forms itself,
or than the extra-capsular "plasm" of a Radiolarian like
ThalassicoUa. I mention this genus especially because a spe-
cies of it which has been well figured and described by Haec-
kel, is frequently used in text-books as a type of the group.
The "meshes constituting the sarco diet yum,"" the "alveoli
of the cal7/mma,*' and the pseudopodia arising in the deep
zone, or sarcomatrix and "forming a network through the
other capsular parts," are the terms in which the "plasm"
of these animals is described. And notice how contrary to
good biological usage it is to employ an anatomical nomen-

242 The Unity of the Orcfanism

clature wliich starts out by calling the major parts of the
body of this organism "plasm," and then names all the de-
tails of organization in keeping with this. It would be quite
as consistent and quite as useful to call all that part of a
fish, for example, situated outside the viscera "extra-vis-
ceral plasm/' and then name the skin, bones and muscles
"dermoplasm," "osteoplasm," "myoplasm."

True Organs in Some Protozoans

But objectionable as is the usual treatment of the term
tissue when viewed from the standpoint of a theoretical biol-
ogy that is adequate and generous, even more objectionable
is the treatment of the term organ. What could be more
absurd than to contend that an animal like Diplodinium (see
figure 1) has no true organs, while one like Stenostomum,
figure 4, has such organs ! No zoologist who becomes so
interested in any of the higher protozoa as to nse above the
theoretical notions into which he may have been schooled as
to what an organ is, hesitates to call many of the parts of
these creatures organs. Thus speaking of his discovery of
what he regards as functionally a supporting apparatus for
the gullet in an infusorian related to Diplodinium, A. Giin-
ther says : "I have found an organ lying in the ectoplasm.
. . ." ^^ Sharp's excellent description and illustrations of
this organ (or these organs, for there are three of them)
in Diplodinium, establish its indubitable right to be called
an organ.

Both historically and biologically there are two criteria
for an organ. One, the more important, is that a part
shall perform a definite office or function in the economy of
the organism ; the other, that it shall be composed of definite
elements to which usually the term tissues may be applied.
As to how the organ in question of Diplodinium measures
up to these criteria, we will let Sharp tell us. Concerning the

Organisms Consisting of One Cell 243

first he writes "That tlie above described structure functions
as a true skelatal (sup[)orting) structure, not only for the
retractile oesophagus, but also for the entire body, seems al-
together certain." ^^ The illustration shows something as
to its composition (figure 1 sK\ lam., indicating skeletal la-
minae). It is composed of plates or laminae, running length-
wise of the organ, and placed edgewise relative to the sur-
face of the creature. This organ is said to be the most rigid
and brittle of any in the animal, and is conjectured to con-
tain silicic acid. One docs well to note the section headings
of Sharp's description : "Organs of Locomotion," ^^ "Organs
of Food-taking," ^* "Organs of Defecation," ^^ "Organs of
Erection." ^^ An examination of figure 1 by the aid of let-
terings accompanying it, will give the reader some idea about
each of these sets of organs.

One of these organ systems must be attended to more
specifically. It is called by Sharp the neuroviotor appara-
tus (labelled in the figure m.m. and circ. oes. ring). The
discovery of this remarkable system may well be regarded
as epochal in the history of knowledge of the protozoa, for
it seems to indicate the presence of a nervous system in
the higher members of this great subdivision of the animal
kingdom no whit less well differentiated and elaborate than
in some of the metazoa and that by no means the lowest of
them. "This apparatus," says Sharp, "consists of a cen-
tral motor mass or motorium, from which definite strands
radiate: one to the roots of the dorsal membranelles (dorsal
motor strand) ; one to the roots of the adoral membranelles
(ventral motor strand) ; one to the circumoespohageal ring
(circumoesophageal ring strand) : and several pass out into
the ectoplasm of the operculum (opercular fibers). Each of
these strands may send off one or more branches. In the
walls of the oesophagus, both nervous and contractile fibers
may be distinguished." ^^

244 The Unity of the Organism

A True Nervous System Probably Present in Some Protozoa

Should further investigations confirm these discoveries, as
one may predict they will, nothing but purely speculative
considerations can restrain comparative anatomists from
putting the nervous system of the Diplodinium type along-
side that of some worms, so far as structural elaborateness
and functional effectiveness are concerned. Of course there
can be no possibility of homology between the two types,
if the term homology be used with the meaning generally at-
tached to it in comparative morphology.

If the possession by a protozoan of a nervous system
thus elaborate should be fully established, the fact would
have far-reaching consequences on our theories about these
animals. A few remarks are therefore in order as to the
probable general correctness of Sharp's observations. In
the first place, Mr. Sharp's statement, "Whatever there may
be of merit in the methods used and the results so far ob-
tained, is due to the kindly and helpful suggestions and in-
terest of Professor Kofoid, under whose direction the work
has been done," ^^ should be noticed. It mav be taken for
granted, I presume, that Professor Kofoid's wide knowledge
of the protista, and his long experience in the technique of
such research as that here involved constitute a weighty
guarantee for the trustworthiness of the results. The gen-
eral "internal evidence" of carefulness, for w^hich well-prac-
ticed biologists come to have so keen an eye, will, I think,
be recognized by all who read Mr. Sharp's memoir. From
the morphological side, the point most open to question is
that of the trustworthiness of the differential action of the
stains used. A modification of Mallory's connective tissue
stain seems to have been Sharp's main reliance, and it is
unfortunate that he does not inform us how this affects fib-
ers positively known to be nervous. Furthermore, it must
be remarked that the seeming identity of staining of this

Organums Consisting of One Cell 245

system and the micronucleus does not fall in very well with
accepted views touching tlie general character of these two
kinds of substance in the metazoa. But the general anatomy
of the system, and its relation to other organs undoubtedly
favor the behef tliat it is nervous. "All parts," says Sharp,
"connected with the neuromotor system act in perfect co-
ordination." ^^ And it should be said that this assertion
was based on attentive study of the living animals. "In
watching these phenomena of retraction and expansion in
the living, active animals one cannot help but be impressed
with the wonderful co-ordination of parts." -^

The idea that neural elements occur in the protozoa is,
as is well known, not new. The most definite report to this
effect previously made, is that by Neresheimer. This au-
thor describes fibers in Stentor running parallel with and in
general accompanying the myonemes. He believes these to
be nervous and calls them neurophanes. The observation
has not been confirmed so far as I am aware ; and one ob-
server, O. Schroder, believes that Neresheimer is in error
as to the existence of any such fibers in these animals. Nere-
sheimer's, and particularly Sharp's, reports will undoubted-
ly call forth renewed studies in this important field.

A More Critical Examination of the Term ''Organ*'

The parts of the protozoa occupied with determining the
creature's place in space are perhaps those to which the ap-
plication of the term organ is avoided with greatest diffi-
culty. "In the majority of Protozoa," says Calkins, "move-
ment is accomplished by the activity of special motor or-
gans, which may be either changeable processes (pseudopo-
dia) or permanent vibratile appendages (flagella and cil-
ia)." -^ This is a favorable place to remark on the justifia-
bility of calling pseudopodia (and other transitory cell
parts for that matter) organs. Science demands consist-

246 The Unity of the Orgamsm

ency. There are many transitory structures among multi-
cellular organisms notably connected with reproduction, for
example the liectocotylized arms of some cephalopods, which
we never hesitate to call organs. And taking the animal
kingdom as a whole, think of the innumerable organs occur-
ring in the embryonal and larval lives of animals ; for in-
stance the placenta in mammals and the gills of frogs in
the tadpole stage. No one hesitates to call these "organs"
because they are transient. As long as this is so, we can-
not consistently let the transitoriness of cell parts stand in
the way of calling them organs.

"The cilia and the stalk (of Vorticella) are definite, per-
manent organs, the first of the kind we have met with." ^^
One can justify the use of the term organ as applied to
the Protozoan by quoting indefinitely from practical writ-
ings by the best authorities. Yet when we come upon defini-
tions of "organ" framed to meet the needs of cellular ele-
mentalism, we find that the practice above referred to would
be illegitimate. Some of these definitions are wonderfully
naive. Take this from the H andworterhiich der Naturwis-
seTischaften,undcv the heading "Organs of the Animal Body."
"By organ we understand, in accordance with the original
sense of the word organori (Werkzeug, instrument) any
body-part, cither internal or external of a multicellular
living being, (Lebeuesen) such part being of regular form,
regular position, and definite, intimate, histological struc-
ture, and having to perform instrumentally a special func-
tion or operation in behalf of the living individual as a whole,
this whole being designated an organism because composed
of such organs," etc.

The naiveness here displayed lies in the recognition of
the term organ as going back in use and meaning to the
ancient Greeks, and in the same breath restricting its ap-
plication to multicellular organisms. When Aristotle recog-
nized that "each sense is confined to a single order of sensi-

Orgmmms Consisting of One Cell 247

bles, and its organ must be such as to admit the action of
that kind or order," and went on to point out that the
organs must be "heterogeneous," (that is, as later anatomy
came to say, composed of tissues); and when William Har-
vey spoke of the heart as an organ and described its shape,
structure, blood capacity, density and movements, and the
passage of the blood through it, beyond a shadow of doubt
these men had a perfectly clear conception of the most es-
sential attributes of an organ, though of course they knew
notliing about cells. And does any one believe that had
they seen the locomotor parts, let us say, or the mouth of
Diplodinium, they would have hesitated, though still wholly
ignorant of cells, to call these parts o