:M€RSON Rl BOOKS BY WILLIAM EMERSON PUTTER 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 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, 1919, BY RICHARD G. BADGER All Rights Reserved This work contains the text of the book: "An Organismal Theory of Consciousness." Made in the United States of America The Gorham Press, Boston, U. S. A. TO MY WIFE MARY BENNETT HITTER MY SEVEREST CRITIC AND BEST HELPER PREFACE 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 authority 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 briii"- a general /oologist 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 that 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 kind, it is these attributes which make him particularly interesting, zoologically shaking — 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, Definition and Classification in Philosophical Biology in my little book, TJie Higher Usefulness of Science, treats of this subject some- what at length. But that to which I attach much 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 synoptic and analytic description, and synoptic and analytic classification? Not until one has come to see that Preface xiii questions of this sort are 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 /oology. Formal biochemistry and animal psychology, that is, the chemistry and the psychology of laboratories devoted to those 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-physieal agencies, and he must at the same time feel the mcagerness 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 the hnmtni animal. Such an attitude toward biochemistry will, I hope, be recogni/ed even by biochemists as calculated to induce at least a receptive frame of mind toward knowledge in this domain. It should IK- 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 highly 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 estimate!* 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 behavior 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 an 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 witli 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 intimacy, 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 lias 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, some 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 Aris- 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 efforts differ 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 effort to recognize a "real world" through combining "ideal form" with "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 ex pn-ss 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 aegis 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 readied 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 Imndling 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 Museum 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. Estcrly, be taken as 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 commentaries 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 xxi 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 J OF THE ELEMENT ALIST CONCEPTION OF THE ORGANISM A. Composition of the Living Individual CHAPTER PAOE I. INTRODUCTORY . . 1 Historic hack-ground, 1. Nature and scope of the undertak- ing, 34. II. THE OlU.ANISM AND ITS MAJOR PARTS 30 He fled ions on the problem of individuality in the living world, • in. The individual plant and its parts, S3. The individual animal and its parts, 89. III. THE ANIMAL ORGANISM AND ITS GERM LAYERS .... 45 The germ-layers, their role in development, and the germ-layer theory, 40. Are germ-layers developmental organs and subser- vient to the developmental requirements of the organism? Ifi. A negative answer to the question in the last section expected of element ulist biology, 4^. Evidence that germ-layers are Unix xiibxcrrient to the organism, 49: (a) Evidence from bud jn-oi>agation in compound ascidians, 50; (6) Evidence from laid i»-o)>a6. The strongly organismal implications of conclusions on the origin and migration of germ cells xxiii xxiv 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 and plants as distinguishable by man, 84. (6) Differences in animal odors as distinguished by animals themselves, 88. The naturalist's approach to biochem- ical problems, 90. Some biochemical results viewed from, the naturalist's standpoint, 95. (a) Reichert and Brown's results on haemoglobin, 95; (6) The precipitin reaction between bloods of different animals, 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; (f) 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 enu- meration 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) Indi- viduation and speciation of "organic matter" fundamental 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 120 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 Brucke's conception of the cell as an organism, 129. Characteristic organization in all cells, 131. Results of later description and classification of cell sub- Contents XXV CHAPTER PAGE stances, 133: (a) Cytoplasm and karyoplasrfi differentiated areas of a common basic substance, 135; (6) Details of cyto- plasmic structure, 137; (c) Three main theories of the struc- i a i-<- of protoplasm, 138; (d) "No universal formula for proto- plasmic structure," 139. Preliminary remarks on the bearing of physical chemistry on the protoplasm doctrine, 140. Ex- perimcnfal erldence for the specificity of protoplasms, 143: (a) Greater fusibility between closely related species as in tissue mixtures and grafts. /f/; (b) Protoplasms and not protoplasm must be the form of the protoplasmic conception, 148. VI. THE ORGANISM AND ITS CELLS ....... 150 What the cell-theory is, viewed, historically and substantively, 1 '•'><>: (a) Importance and general character of the theory, 150; (b) Various forms of the theory as currently held, 150; (r) Statement of the theory justified by present state of knowledge, 154. Certain ln«dere!oi»itent, 158; (b) As tested by isolated cells and tissues, 167. VII. THE CELL-THEORY NOT SUFFICIENT FOR EXPLAINING THE OR- (1 AN ISM ........... 179 More general inadc_'. K.rperimental facts on irhich the theory rests, 202. lialancini/ the account hefireen the mosaic and totipotence theories, 206. The "i>romorphology" of germ cells, 211: (a) Facts of immediate ohscrralion on which the con- ceji/ion rests, .'/.'; (l>) (, 'round* for believing minute observ- able specific differences between germ cells important, 214! xxvi Contents CHAPTER PAGE (c) Reflections on a promorphology of germ cells beyond the • limits of visibility, 222. IX. ORGANISMS CONSISTING OF ONE CELL 227 A. Adult form and structure. Remarks on the conception of the cell as an elementary organism, 227. Comparison of the structure of a single cell with that of organisms composed of many cells, 230: (a) Comparison of certain dilates and metazoans, 23%; (6) Comparison of a radiolarian 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- A 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 make protista conform to cellular 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 305 Heredity the chief present-day stronghold of biological ele- Contents xxvii mentalism, 305. This due particularly to discovery of inter- dependence between adult characters and chromosomes of germ-cells, 30C. Revised conception of heredity essential to interpreting thin interdependence, 307. Unwarrantable tend- ency to restrict heredity to sexual propagation, 308. Unwar- rantable tendency to restrict heredity to adult characters, 811. Importance of recognizing heredity as working by transforma- tion rather than by transmission, 312. Tendency to confuse hi-n-ililif irith riiimt'it of heredity, 313. Definition of heredity adopted iii (hi* discussion, with remarks on its application to flic chromosome theori/, -U ',. Meaning «>id criterion of "mech- anism of heredity," .:.'.'. XII. KVIDEXCE FAVORABLE TO CHROMATIX AS HEREDITARY SUB- STANCE 3?H A. Direct Evidence. Evidence from tin ontogeny of some ' protozoans, 326. Evidence from certain cells of multicellular organisms, 331. Evidence from gpennatozoan. .133. Evidence from pigment cells, 333. B. Indirect I'lridcnce, 341. The chromosomes of germ-cells in fertilization, •!'/.'. 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, 353. Chromosomes and the Mendelian mode of inheritance, 356. XIII. KVIDEXCE FROM PROTOZOANS TlIAT SUBSTANCES OTHER TlTAN CHROMATIS- ARE PHYSICAL BASES OF HEREDITY . . . 363 Evidence from the ontogeny of various protozoans, 363: (a) Stentor. .sn.:; (l>) \Vhrol>lankester) . 388 31. Fpimerite of Eehinomera Hispida (After Lankester) . . 388 3.->. Fpimerite of Beloides Firmus (After Lankester) . . .389 W. Fpimerite of Comeloides Crinitus (After Lankester) . . 389 34. Xoetiluea Miliaris (After Hertwig) ...... 390 35. Fission Stages of Noctiluca Miliaris (After Calkins) . . 391 XXJX 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 EYKUY biologist is familiar with the phrase "the organ- ism as a whole." It occurs over and over again, par- ticularly in later years, in written and spoken discussion touching a wide range of subjects; and the essential idea, expressed in different terms, 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 tin- 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 Parts 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 formed ... 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 the ages-long controversy lie 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 Empcdocles and Epicurus, his formulation of biological elementalism is so explicit and so readily accessible to modern readers that it will serve well the needs of this discussion. In the third book of The X at tire of Things Lucretius gives his reasons for rejecting the Greek notion of the "mental sense" of man and animals a> 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, independent, 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 yet is this nature or substance to be regarded by us as simple and uncom- pounded. For a certain 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." 2 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 elcmentalist theory. 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, with Bichat leading, came the advance to the tissues ; then before long the discovery was made that not the tissues but the cells are the real units of structure, Schleiden and Schwann being foremost in this Introductory 5 forward step; and finally, with the demonstration, ac- complished chiefly by Max Schult/e, 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 arc 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 tlie 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 Genera Plantarium, 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 orgcinizcd 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." 4 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 his 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 marshal] facts, it was exactly Introductory 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 Geoffrey 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; (£) 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 organ, normal or pathologic, never acquires an unusual prosperity, without a related organ, or one in the same system, suffering for it." 5 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) arc 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 Itr necessary to examine somewhere, probably at this point, the ideas of the oryanicixls, a group of embiyologistfl 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 Animals 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. Bichat, W. His and K. 1'm'iger as representative of this group. The philosophical importance of the ideas held by these investigators has been emphasized by L. J. Henderson (The Order of Nature). But there is, as I believe, a vein of subjectivistic 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 Sehwann'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 chwamfs 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 rat her 'as an interpretation of cells in accordance with an ancient idea well known to him and opted bv 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 sav that through the influence of the cell theory as promulgated by Schwann, following as it did close upon the foundation of histology by Hichat, the organismal con- ception lay almost wholly dormant (luring the fifty years from 184-0 to 1890. :::,. 10 The 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 which, 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 theory 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. However, one highly significant circumstance must be noted: the rehabilitation has had little or nothing to do with the form assumed by cl ;; be Introductory 11 the theory in the hands of the French biologists considered above. It has on the contrary arisen in a sense de novo, and in consequence of a growing recognition of the inadequacy of elemental ism as bodied forth in the 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. "hitman, E. B. Wilson and F. R. Lillie. Whitman, as is ell known, was primarily an embryologist, his best re- arches having been on the development of leeches and jny fishes, and his observations in this field were the start- ing point for his views on the relation existing between 11s and the organism. In his essay, The Inadequacy of the 'ell-Theory of Dei'elopjnent, he says : "Comparative em- ryology reminds us at every turn that the organism domi- nates cell-formation, 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 may so speak." T 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."8 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 the 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 Development 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 arc 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, Chaetopterus pergamen- t(ic(iiK. 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 developmental 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 be made concerning the differen- tiation of the uninucleated eggs. (1) Organs are never formed, but only -such structural elements as may occur in single cells of the trochophore. (^) Organs may, how- cvcr, 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 *ituatcd near the upper margin of the yellow endoplasm which simulates the row of vacuoles of the prototroch. ('$) 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 ollowing: "The possibility of a considerable amount of bryonal differentiation without either nuclear or cyto- asmic division may be considered established. This in it- self is an important fact, for it disposes effectually of all theories of development that make the process of cell-division e primary factor of embryonal differentiation, whether the form of Weismamfs qualitative nuclear division, or ert wig's cellular interaction theory. Further, the phe- nienon establishes firmly, as I pointed out in li)01, the iew that the role of cell-division in development is prima- ily a process of localization.11 Lillie presents his still broader interpretation in an ex- ingly interesting section headed "Properties of the hole ( Principle of I'm'ty)." From this I quote somewhat ore at length than is essential for our immediate purpose f gaining a bird's-eye view of the field \ve are entering, since ater we shall want to examine several of the items more closely. "The traditional view, held by main 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 y 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- j 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." 12 . . . "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." 13 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 has 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 Introduc tory 15 processes cannot be referred to cell-division, to what can they be referred? To cellular interaction? . . . Tin- answer . . . will ... as Wicsner has so well insisted, find a common basis for every grade of organization. It will find 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, with 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, the position he held in 189*5 was somewhat backward from that which he held five years before, when he wrote The •at of Formative and Regenerative Energy, for in that y he said: "Let us now consider whether any rational sis can be found for the idea of a formative power as a suit ant from, and an expression of, physiological unity, am fully conscious that the subject is one of profound stery, the solution of which appears to lie as far beyond grasp to-day as at any time in the past. We draw rer to the problem, but the effect is rather to enhance n to reduce its apparent magnitude. Every step in ad- ce only brings us to a keener sense of the subtle and mprehcnsible nature of the force or forces conteni- ted." 15 The extent and nature of Wilson's faltering between the wo standpoints, even as Ix'tween the organism and its cells, in tfpite 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- J. A \Jll Seat essa basi 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" ;10 and the conceptual form which the material particles, by virtue of their "particular relations and properties" assumes in Lillic's mind is the "formative stuffs" which, since the theory of such sub- stances was first given definiteness and plausibility by Julius Sachs, have figured largely in speculative biology. "The theory of formative stuffs," Lillie writes, "does away witli any 'determinant' hypothesis. 'Characters' are not due to 'unfolding' of the 'potencies' of 'determinants' 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." 17 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- lilt- the tha loo sidi Introductory 17 vcy lias traced from the period of Aristotelian zoology, through that of French comparative anatomy of the late eighteenth and early nineteenth centuries, through what might with propriety he called the period of American em- bryology, now barely ended, holds its unmistakable course on into what we mav speak of as a physiological period, in the midst of which we now are. It should be remarked that "physiological" as here used does not refer so much to physiology 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 organismal theory arc not primarily physiologists but students of individual development. The term most characteristic of this latest outcrop of organisinalism 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 that now the correlatedness of parts in the organism is being ked 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 another term that is frequently used bv the biologists whose thinking is of this cast, and he 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 ('. M. Child, though numerous investigators are con- tributing important ly to it. K. (ioehel, F. Kadi, W. Pfeffer, L. .Tost, J. Nusbainn, F. Scliult/, II. Kand, S. J. Holmes and C. Zelenv mav be mentioned as biologists who have dealt more or less directly with the problem. Undoubtedly II. 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 Unity 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. Roux, 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 Entwicklungsme- chanik der Tiere und Pflanzen. Thus as a definition of or- ganism we find "Organism means a complex of organs ; hence, of instruments." 18 Or for living being (regarded as a syn- onym for organism) we find: "Living 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." 10 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 the most characteristic thing about developmental Introductory 19 mechanics as a system of thinking on biological subjects is its effort to deal with organisms in terms of parts of or- (jtutitfuix; 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 elcmentalism 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 elementalisin is far more genuinely biological and scientific than is, for example, the purely chemical form of eleinentalisiii, 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 elementalisin, far more superior are they to that form of elementalisin 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 metaphysical conceptions of this type all prove to 20 The Unity of the Organism be so noxious to scientific biology \ve 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-charactcr-f actorial-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- e'st 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 clementalistic 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 important 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 hud 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 gem-sis and not merely of genesis from germ-cells toward soina. 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 rctltictio ad absurdum 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- wa\ movement, that wav being from invisible germ to visible organism. Finally, 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'y 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. £2 The Unity of the Organism How far theorizing has gone on this road is indicated by the much noticed address by William Bateson, one of the foremost Mendelian geneticists, as president of the British Association for the Advancement of Science in 1914. 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 formal 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 determiners, or fac- tors, of all later visible organisms, and from which these issued by the transformation of latent into actual organisms through 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 enterprise will never be carried through, seriously, is that the organismal stand- Introductory £S point has already advanced so far on secure observational and experimental and inductive foundations, that the scien- tific useless ness if not folly of such elcmentalistic 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 this 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 theory 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 Avill 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 the Handworterbuch 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." 21 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 organismalism as contrasted with chemical elemen- talism is well brought out. ,s, si SU CO .1. 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, should 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. unanaly/.ed : 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 to combat, incidentally but yet vigorously, this view. Stated positively, while assuming as science always does as- sume, the validity of analytic knowledge of nature, we shall ntend that synthetic knowledge of nature is not only valid also, but that it is as foundat iona] and essential a part of science as is analytic knowledge. Furthermore we shall touch briefly, but as we believe very fundamentally, the question of the nature of synthetic knowledge itself. In accordance with tliis 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 serviceable, and as in- dispensable to science as are "foot" or "head" or "brain," or '"eye" or "muscle" or "cell" or "ovum" or "nucleus" or "chromosome" or "nucleo-proteid""1 or "ptyalin" or any other fully accredited and uneseapable biological entity. Let me state the case from a slightly different angle, attach- 26 The rtrity 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 whole 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 docs 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 shah1 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 terms 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 forth efforts that have been made in recent and present-day biology to deal with several great classes of the constituent parts or elements of organisms in accordance with the elementalist theory. If my basal proposition be true that the 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 as>ii>n 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 dueed 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 tlie Organism 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 fully established inductive evidence which, if fairly 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, organismalixm. 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 up and carrying it with us. But perhaps the possession of such power as this is just what entitles new words to live. If so, and should the idea prevail for which the word stands, the word will prevail too unless some one having special com- petency in fabricating words finds a better. Which of these In troducto ry 2 9 alternatives may befall is immaterial. 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. Locy 139 1. Mere II, 240 :>. Saint-Hilaire 214 (j. Sc-hwann & Schleiden 191 7. Whitman ('93) 119 S. Wl.it. nan ('88) 49 <). Wilson ('93) 9 10. I.illic, F. R 237 11. Lillie, F. R 245 12. Lillie, F. R... 251 13. Lillir, F. R 202 11. Whitman ('93) 123 15. Whitman ('88) 43 If). Lillie, F. R 253 17. Lillie, F. R 258 18. Roux ('12) 287 19. Roux ('12) 241 ,'(). Roux ('12) 163 21. Hanclworterbuch II, 736 Chapter II THE ORGANISM AND ITS MAJOR PARTS Reflections on the Problem of Individuality m 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 attempted to find a solution to the puzzle of individuality 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 so1 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 "points" 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 SUl 77*6' Organism niiJ UK Major Parts 31 While the individual plant does not appear quite so con- spicuously in plant husbandry as does 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, ~ we shall see presently, some speculative botanists have ne to the ridiculous extreme of asserting that there is no ch 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 exactlv what we are here discussing. For anybody to contend that one of these beings — the man — is an individual, while the other — the tn-c 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 unescapablc 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 with 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 almost all cases is exceedingly complex. ml an po F lei The Organism and its Major Parts 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 been 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 d 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. e points out that their importance, so far as the prob- rm 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 Organism made to interpret the organism in accordance with the theory which denies its individuality. 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."1 Again: "In the plant community the activity of every cell and of every organ is subservient to the common weal, and may, when1 necessary, be modified as already indicated so as to fulfill the changed requirements of the whole."2 It is true, I believe, that the mode of thought about plants illustrated by 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 observation. 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 Phylogenesis 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."3 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."4 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, Schleiden's brand of clementalism necessitated the sacrifice of the individuality of the plant to that of the 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 dciwloping plant was an obstacle to his theory, even though he seems not to have been aware of the fact. "After the woody 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 plant in all its parts."5 Schleiden seems to have felt no difficulty in his conception that the "law of formation" which "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" should IK- 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 Conroluta roscoffcnsi.s 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 symbiotic complex, "much that has been dark in the vegetable world becomes clear."6 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 generally 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."7 These "associated individuals" Mr. Davidson calls plantagens 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 effort is seen in the fact that both the asexually and sexually propagating elements of any The Organism ami 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 the 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 that 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- iigens, 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 form 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. 38 The Unity of the Organism 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 plant agens, 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 sempertnrens). A stump of this tree, even a stump that has passed through a severe * The question of adventitious or cambium buds from lemon trees sen i is not to have received much attention from botanists. Judging from the distribution of the new growths in such an epidemic, as it might be called, of budding as that which takes place under conditions like those here mentioned, there is scarcely a doubt that very many of the new branches arise quite independently of previous bud germs; in other words, from some source not germinal until it becomes so under the special conditions. The only experimentation on bud production in the lernon with which T arn acquainted has been carried on by Prof. II. S. Reed of the Citrus Kxperiment Station of the University of California, at Riverside. Doctor Reed has kindly shown me the results of his work and permitted me to make use of them in this connection. So far as these experiments go, it seems that while leafless pieces of branches kept under suitable conditions readily put out undoubted cam- bium buds, these produce roots only. The Organism 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 has 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, ea'ch 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 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- (ilasm and plantagens is unmitigated sophistry. The Indiiidual 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 groundwork for certain elementalistic conceptions of the organism which, viewed in their historical 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 Anvmalwm of Aristotle (Book I, 722b, 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 lichen. The kinship between such a speculation as that of Empedocles concerning the origin of the individual and the modern speculation which would have the individual arise symbiotically is unmistakable. The most important likeness between the two conceptions is the fact that both are fundamentally rfco-w-evolutional. The isolated heads, necks, legs and arms of the ancient Greek, like the germ- 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 of the heads, legs, etc., or of the germ-cells and germ- Is, but the origin of actual animals and plants from the ?spective elements once the elements are at hand. In a ford, expressing the limitations on this mode of theori/ing the familiar language of Darwinism proper (not neo- Darwinism), 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 by 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 Unity of the Organism curity in something or other to which the word genesis can be attached, but which can yet be conceived as not sub- ject to transformation, 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 who 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." 8 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 merely 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 ontogeny especially. The Organism and ?'/.? 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 the lower animals like the coral polyps, where secondary individuals are produced asexually but do not become wholly 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 9 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 metagcnetic group-individuals, such as are found in many of the eoeleiiterates 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 Unity 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 1. Pfeffer 18 6. Davidson 407 2. Pfeffer 27 7. Davidson 405 3. Schwann and Schleiden.. 258 8. 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 OTRK'T fidelity to the natural sequences of biological ^^-J 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 uniform 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 arc 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 ern- 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 inon- 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 many groups split into two, thus making a four-layered stage); and the innermost, called the cndoderm. 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 mucous 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 endodcnn: "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 rmphatic system. The lining membrane of the serous cavi- 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 f these animals. My observations being a confirmation and extension of those by other /oologists on other species, not- ably by the older zoologists Giard and Kowalevsky, and in ic period of recent methods, by Hjort, there can be no >tion that the nervous system arises in some gemmipar- ously produced ascidians, from the inner germ-layer whereas in individuals of the same species 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- derin but ectoderm, this resulting from the manner of de- velopment in the parent of the laver from which the inner vesicle originates. There is 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 nervous 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 aU tunicata. This is equivalent to saying that the ectoderm 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 Animal Onjniiism- ami its Germ-Layers 53 ably constantly renewed. This production may, as Hjort had 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 favorably 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 be here transferred to the endoderm? And so K i_ This conclusion is the more justified when one considers w differently circumstanced are the two layers in the bryo. Here the incipient nervous system arises from the ectoderm 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 Tl\e Unity of tlie 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 egg. A good summary of the view most commonly held by specialists in this field is given by Harmer.4 "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-sheath, which is always in the condition of retrac- tion. The lower part becomes thicker; its inner layer gives rise to the lining of the 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 mesodermic 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 with the structure and development of the bry- ozoa, the point of central importance to this discussion is clear enough : The outer layer of the body wall gives rise to the inner layer of the bud, and from this 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- ;is = The Ati'nnul Ortjanixtii rocedure, we must look at it attentively. Assuming that reismann and Goette are equally endowed by nature and by lining as observational biologists (and I have no doubt great majority of unbiased zoologists who know the >rk of the two men would allow this), it must be granted lat Goette as pitted against Wcismann does not constitute disproof of the hitter'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 prc- 64 The 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 work 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 endoderm in some species, so that Weis- mann's assertion that in this group they always arise in the ectoderm is wrong. But of far greater importance, Goette shows that not only the endodermal but also the ectodermal 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 germ plasm 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 65 as a particularly clear case of the genuine transformation of endoderm cells into sex-cells. To be still more explicit, in his figure (115 plate V,) is shown a sex-cell so slightly differ- ent from the neighboring endoderm 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 endoderm 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 Scrtularella; and he then remarks: "From these observations it becomes unfair to assume that in other cases where germ cells arc found in the endoderm that they have wandered from the ectoderm. Proof of this must be absolute." 8 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 Corydendrmm para^siticum. He saw here no less )sitively than did Goette, very young stages of the cells in ie endoderm; but since, he says, he could not find the ab- )lutely first stages "the possibility of the ectodermal ori- gin of the sex-cells is not excluded." ! In other words, the ?nce of absolute proof of the endodermal origin of the •Us is used to support the n /triori conclusion that they irise in the ectoderm! So far as the observational evidence this specific case goes, it strongly supports, as \Ycismann limself grants, the conclusion that the reproductive cells arise' in the endoderm, hut since the evidence falls a little short of finality if may be cast aside wholly in favor of purely theoretical grounds for supposing the origin to be Isrwhere! Against this method of reasoning Goette strongly protests, and every biologist who genuinely be- Heves 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. 0 Weismanrfs 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 germ- 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 hydromedusae 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 ("gebunden"), 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, migrates into the endodcrm, and so ex- plains the participation of the endoderm in bud production. Goette's conclusions as to the actual endodermal origin of sex-cells in the hydroids are not unsupported by other workers. Tlius Tichomiroff liolds that the sperm cells of Kudcndritun (uircntuim arise in this layer, and C. W. Har- gitt, who has devoted much time to the question, is unquali- fied in his statements. He writes in a summary presentation of his results : "It may be said that while in Eudendrium ramosum 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 diapar 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 endoderm 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 indifferently with either cctodcrmal or endo- ermal material and reach the same end as seen in different genera of the hydromcdusa>, 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 Kewnst'dtte in different species of Etifft'inlriHnt, perhaps indeed in the same spe- cies, changes." J1 Finally, and as a cap-sheaf to the arguments here pre- •nted in favor of the view that sex-cells do arise genuinely anew in each individual in the hydromedusa?, 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 germ-plasm did he come to repudiate this view. On page 284 of the monograph we find 68 The Unit if of the Organism the following: "After all this, there- can he no doubt that the germ cells may reach their differentiation and separation from somatic cells only when the germ-layers have long since lit en formed, and it is impossible to accept' as a genera] law the view of Xnxxbanni. that sex ceils are 'absolutely indepen- dent of the germ layers.' So far as we can now see, the sex- cells always arise in the hydro ids from elements of one of the germ-layers and they are not merely inclusions in a germ- layer but are derivatives, are division products of it." Stripped of all sophistry, how is it possible 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 by 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 hydromedusa- 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 Strongly Ory(ininmrates has been studied by several /oologists, among them ing C. H. Kigenmann and H. M. Allen. Allen's investiga- ms are specially important because of their wide com- irative scope. In The Origin of the Sex-Cells of Amid and isteus he gives a set of useful diagrammatical com- irative drawings showing the mod;- of origin of the sex- rills from the endoderm of a reptile ( Cli r/y.vo /////. v), an am- phibian (Frog), and two fishes (Anna 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 Relation 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 observational facts. REFERENCE INDEX 1. McMurrich 79 8. Goette 63 2. Minot 250 9. Weismann ('83) 42 3. Ritter ('96) 183 10. Hargitt 240 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 Standpoint of the Discussion that of the Evolutionary Naturalist PHYSIOLOGISTS 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 lx.«en, without exception, natu- ralists primarily. The three names that stand out with mountain like conspicuousness among those who in modern 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 laboratory production, of organic compounds, he can be in no wise satisfied until he has been to^I 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 with such questions. In fact it seems as though the evolution doctrine had not made the slightest impression on many biologists animated by the chcmico-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 physical 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 hostility to evolution, to tin- conception of origination by transformation and Drouth. But this is no place to deal with the yast 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 .siib.stanci > is to be that of tin- evolutionary natu- ralist. We are to push our studies of the structure and function (the morphology and physiology) 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 those 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 we 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 tin4 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 the 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 quest ion among chemists themselves. 78 The Unity 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 d>en 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. ( Sec, for example, Max Verworn, p. 596, Allegemeine Physiologic, sechste Aufl.) The Organism as a Chemical Laboratory Immediately the fertilized egg begins to develop, chemical substances are produced within it. Among the higher ani- mals the hen's egg has been the most studied in this as in many other aspects. "Neither nucleo-proteins nor pentoses are present in the fresh egg, 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 phosphorizcd fats) takes place during development."1 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 myosin of striated muscles, the various enzymes of the digestive glands, the neurokeratin and protagon of the central nervous 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 sharply dis- tinguishable sorts when the total chemical make-up of the developed organism is compared with the total make-up ped: 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 rfiscorerics of great /Kirtancr arc here cnJcnf absolutely on one of the naturalist's most cherished methods, the comparative, the 94 The Unity of the Organism chemist having, however, surpassed the naturalist 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 purpose; 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 biochrni- The Organism find itx Chemistry 95 istry become systematic biochemistry? How far lias it un- dertaken to contribute to the vast task of describing and classifying and interpreting the world of living beings? Or varying the form of the question a little, how far lias biotic chemistry become biologic chemistry? How far has the chemistry of organisms become biologically scientific in the systematic sense? Some Biochemical Results Viewed from tJie 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. Rcichcrt. 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, Rcichcrt was obliged to associate himself with a mineralogist, and that in his university colleague, A. P. Brown, he found a man both capable and willing to undertake the task. (ti) Rcichcrt 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. Rcichcrt 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 Muridae, and no difficulty was ex- perienced in forecasting similarities and dissimilarities of habit in Sciuridae, Mwridae, Felidae, etc., not because hemo- globin is per se the determining factor, but because, accord- ing to this hypothesis it serves as an index (gross though it be, with our present knowledge) of those physico-chemical properties which serve directly or indirectly to differ- entiate genera, species, and individuals." 15 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 C'finifi and Felis, a number of species and varieties \M if included. The crystallographies method was used almost exclusively in the investigation. Concerning the value of this method for recognizing chemical 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 physical structure, and the crystallographic test of the differences of chemical consti- tution is recognized as the most delicate test of such dif- ferences," 1G In accordance with this the dictum, "Sub- The Organism and its Chemistry 97 stances that show differences in crystallographic structure are different chemical substances" 1T 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 "each 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, UK Hiemoglobin; 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- niorphous series, tlie 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." 18 In illustration we may select the table for the species of cats studied, this being based on the crys- tals of reduced hemoglobin. The 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 mii/ Angle of .\tinn of XjH'firti .Li-itil rn/io prisms (normals') macrodome normals Felis leo 0.9743:1:0.3707 8830' 4150' F. tigris 0.9742:1 :0.3S:W 8830' 43 0' I-', lirnji-Mlmsis 0.9657:1 :0.3:l :0.393l 87 0' 45 0' I'. (Idiiiivstic.-. 0.9(i.5(i:l:0.:W39 88 O' 4320' Lynx fufus <>.<»s tals and kinds of animals, is that the crystals have not been described icitli sufficient fulness and accuracy. In a word the issue is, to the naturalist, the old and familiar one of description, comparison and cl-a-xx'tficution. For example, the authors lay particular stress upon the insufficient atten- tion hitherto given to the crystal forms 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 determination! of the axial relations and other phys- ical attributes of the crystals. The upshot of their criti- 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 tli.orou(/h(/oin(/ description, that classification correlates itself with the kinds of animals from which the blood is taken. (b) The Prcclnltln Reaction llcticccn Woods 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, woulcl 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, which though not as directly chemical 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 are the discoveries of recent years touching1 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 opposite 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 individual, 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 is that of the production within the organism of a nil- bodies as a result of injecting into it certain foreign sub- stances which, when the reaction occurs, are known as anti- gen*, the anti-ye-nx 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 Organism and it.s Ckemigtry 101 and the antibody. The point of special significance for us now is that 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 seriim thus af- fected was then used for experimenting upon the serum of a normal sheep, a goat and an ox, with a view to testing quantitatively 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 preeipitin, 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 precipitin 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 scrum, but that there are really three precipitins involved. This conclusion, Arrhenius points out, srems 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 Fishes Several biologists are impressed with the importance of knowledge in this 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.23 The march of research in tjie 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 rcsarch 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 Miescher and continued by Kos- sel and his students, on the spermato/oa of fish. Miescher discovered in the sperm of the salmon a group of protein substances called by him protamines, which arc said not to have been found as yet elsewhere than in fish sperm. The Organism and its Chemistry 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 C32H54Ni8O4 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 salmine, clupeme, scombrine, sturine, cyprinine, cyclopterine, etc., proposed by Kossel have consequently come into general use. These differ in formulae. Thus Kossel gives clupine as C3oHC2N14 00 and sturine as C3flHfloN1907. 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. (eriments), it turns out that the in- hibitant from the rennet of one species does not inhibit the en/vme 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 method. 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, '- naturalist Inquiries A rough-and-ready enumeration and classification of the chemico-transfoi matory 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 which plants utilize water and the in- organic elements of the soil to their needs. li. 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 tissue's 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 which the chemical substances dis- tinctive of organic varieties, species, etc., are originally produced, the phytogeny, 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 CJiemistry to the Chemistry of Liiitnj 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 Specuition of "Organic Matter1' Fundamental Biologic Facts That some physiologists are not fully awake to tin- sig- nificance of certain of their possessions is shown, I think, by the following appraisement of plant productions that arc 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 what use to a toad a rise of blood pressure in the animal which attacks it would 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 mav 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- ern naturalist has outgrown the old practice of putting aside whatever he can not explain as accidental or abnormal. Hut 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-Darwinian 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 service 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 jt is in its most obvious, most practical expression, 114 The Unity of the Organism It is this : Arc a man and a dead man, a horse and a dead horse, the same thing or are they different things? If the materialistic biologist and the vitalistic biologist will answer this question with an unfaltering "They are different things," and wih1 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 vitalism, 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 chemis-try 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 they 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- dividuated in a strict sense, lias no better standing in the world of objective reality than have the ghosts and other apparitions with which the imagination of primitive men populates the world. All 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. (b) Indication* That Variation and Indwiduation 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 thus derived, see how in their very nature 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 production*] 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 tin- 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 Unity of the Organism And since physics and chemistry have fused together as regards many phenomena 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 existence 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 we now know it is not a mass of matter composed of a congregation of like molecules, but a highly differentiated system ; the cell, in the modern phraseology of physical chemistry, is a system of co-existing phases of different constitutions. Corresponding to the difference in their constitution, dif- ferent chemical events may go on contemporaneously in The Organitm (tinl it* CKcuriitry 117 different phases, though every change in any phase affects the chemical and physico-chemical equilibrium of the whole system. Among these phases arc to be reckoned not only the differentiated parts of the bioplasm strictly defined (if we can define it strictly) the macro- and micro-nuclei, nerve 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. They must be held, too — a point which lias 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 aihorptive 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- thors) 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. By its purely physical properties, its spacial and energy magnitudes and changes, the cell is primarily quantitative, while by its chem- ical properties, its transformation 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' phrase, for bringing about "dynamic chemical events," events, that is, which are qualitatively transformative. So our appeal as naturalists to physical chemistry for help in interpreting the substances of which organisms are composed is carrying us toward some such conception as to their individ nation, 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, hy VV. Punli, in Physical Chemistry in the Service of Medicine, translated by M. H. Fischer. The Organism and its Chemistry 119 have not yet examined all the 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. K INFERENCE INDEX 5. (i. 7. 8. 9. 10. 11. 12. 13. 14. Marshall .............. 269 15. Marshall .............. 293 16. Tan-le ............ 423; 327 IT. (a) Thierfelder u. Stern 18. .................... 370-385 19. (h) Tangl u. Fa rkas. .624-638 20. (c) Marshall ......... 267-273 21. Brooks ................ 325 22. Bayliss ................ 19 23. Hopkins ............... 216 24. Hopkins ............... 217 25. Deniker ............... 109 26. Hopf .................. 240 27. Brddard ............... 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 566 Marshall 366 Hardens 363 Taylor 343 MM thews 465 Bayliss 727 Hopkins 220 Chapter V THE ORGANISM AND ITS PROTOPLASM Protoplasm and Mystification 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 approaching the protoplasm question from this 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 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 well as a scientist, and of a highly imaginative, sensitive nature.1 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,2 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 tlu- value of the term, still admit that "on many sides the word is used in different ways." For Max Schult/e, 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 Schult/e wrote the phrase just quoted, and 1912, when (). Hertwig last, defended the right of the term to exist even though used in many different senses; for by so doing 122 The Unity of Hie 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.4 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 higher 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- Tl\e Organism and its Protoplasm ing the structure of organic beings should 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 tin- "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 fast-mentioned fact [the chlo- rophyll function of green plants] it may be truly said that the acts of all living things are fundamentally one."6 "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." 7 Conception of Animal Sarcode and Plant ProtopUum us "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 object ionableness of all dogma in science. "Subsequently, Max Schultze and de Bary proved, after The Unity of the Organism most careful investigation, that the protoplasm and the sarcode of the lowest organisms are identical" l "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 hW received the title of 'the father of biology.' " l "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 light 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 wholly removed, and that 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 have to be to the effect that a dog would be strictly himself and as well off with a tree's protoplasm 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 inaturest and best, one finds that not only did they not teach the identity of protoplasm in all living beings, but that what they did teach was some- thing very different. Ferdinand Colin, 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. u Mitx Schidtze's Actual Teacluuyx ax to Protoplasm and Sarcode In 1861, after a great many trustworthy observations had been made in widelv separated portions of the organic realm, of substances so closely resembling one another, came Max Schult/c with the essay which gained for him the widely recognized title k4the father of modern biology." Kxactly what did Schult/c aim at in this essay? He was primarily concerned with the nature of the cell and not of the proto- 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" L2 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. (a) 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." 1S 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 the nucleus. The On/tiHixni