WHAT IS LIFE? BY AUGUSTA GASKELL WHAT IS LIFE? BY AUGUSTA GASKELL INTRODUCTION By Karl T. Compton Professor of Physics, Princeton University By Raymond Pearl Professor of Biology, The Johns HopJcins University CHARLES C THOMAS SPRINGFIELD, ILLINOIS - BALTIMORE, MARYLAND 1928 Copyright 1928 by Charles C Thomas First Published in 1928 Manufactured in the United States of America Introduction By Kakl T. Compton Professor of Physics, Princeton University Introduction THE question "What is Life?" is undoubtedly the most fundamentally important problem of science. In seeking its answer, an enormous amount of information has been gained in regard to life processes, but the basic question is still unanswered. In fact, the very complexity and wealth of infor- mation about life processes have dispelled hope of any easy or simple solution of the central problem "What is Life?" It is to be expected, therefore, that any suggestion of an answer to this question should meet with skepticism. And, in the nature of the case, such an answer can at best be but an hy- pothesis, since there are no scientific observations which are believed to strike sufficiently near the roots of the problem of life to justify any claims to certainty. The utmost that can be demanded is that any attempt to answer the question should be a good working hypothesis, susceptible of test, and not inconsistent with well established facts and scientific principles. 7 TyV WHA T IS LIFE The author's answer to the question "What is Life?" purports to be based on the facts of modern atomic physics. The first query that will naturally occur to the serious reader is in regard to the author's qualifications in the field of physics. To this I would say that her discussion of modern atomic physics is accurate, well balanced and worth read- ing for its own sake. The second query in the reader's mind will refer to her knowledge of biologi- cal, or life, processes. This I am not qualified to answer, but I can testify to having read her ex- position of such matters with much interest and admiration of her evident knowledge of this field. The answer to the question "What is Life.^" is essentially found in the hypothesis that protons and electrons, in addition to forming by their various known combinations the ninety -two kinds of atoms, are also able to unite in combinations of a type as yet undiscovered and which are the "active" or essential ingredients of living matter. These so- called "Z" elements combine in specific ways with the ordinary known chemical elements to form living matter. Living matter is thus a "dual" system, whose basic constituents are protons and electrons. By analogies, reasoning or by further hypotheses, various life phenomena are then inter- preted by this "dual" structure. INTBOD UCTION The honest physicist must admit that he knows no independent experimental evidence to suggest or support the hypothesis of these assumed "Z" com- binations of protons and electrons. He must also admit that he really knows relatively very little about atoms, protons and electrons, and nothing at all about the explanation of life. Hence the author's fundamental assumption must be admitted as pos- sible. Further, she has shown how it can be used as a working hypothesis in a variety of directions. Finally, it should be susceptible of experimental test. These considerations should support the au- thor in her plea for serious consideration of her work on its merits as a stimulus toward an experi- mental test of her theory. The decisive test of this theory would involve the proof or disproof of the existence in living matter of combinations of protons and electrons in a dif- ferent unit structure from the ordinary atoms of the inorganic world. Failing this, there are certain possibilities in the nature of indirect evidence, such as the generation of life by some such combination of circumstances as described by the author as a "critical concentration of ions," or the energy trans- formations which would be predicted by the theory at the instant of death. In conclusion it is scarcely necessary to point out 10 WHAT IS LIFE that the author's work cannot be judged dogmati- cally, for the obvious reason that it deals with a phenomenon which has thus far resisted scientific analysis. The book stimulates serious thought and it is to be hoped that it will contribute to the suc- cessful solution of the problem "What is Life?" Karl T. Compton. Introduction By Rayiviond Pearl Professor of Biology, The Johns Hopkins University Introduction THE theories about the origin of Hfe upon the earth which have hitherto been promulgated by biologists and others have had the charming quality of naivete, but have not, on the whole, been other- wise convincing. Furthermore, they suffer from the common defect of lacking any possibility of experi- mental test. Perhaps primitive living substance did ride from somewhere to the earth some time ago, on the back of a meteorite, but precisely how is one to prove it? Or, perhaps, as Arrhenius urged, some spores came here from somewhere else on their own. But again one's only epistemological resource in dealing with such an idea is that kind of faith which sustains the embattled spiritualist in his struggles with scoffers. That basic doctrine of biology, Omne vivum ex vivo, is, of course, in the absence of any rigorously defined concept of life, a perfect example of dogmatic mysticism, when philosophically considered.^ And, ^ The objection will at once be raised that Omne vivum ex vivo is a state- ment of fact, not of dogma. But the crucial evidential basis lies only in the circumstance that the implied opposite has not yet been objectively demon- strated. 13 14 WHAT IS LIFE as is the effect of all accepted mysticism, it has almost completely estopped any attempts at re- search on what is plainly the most fundamental of all biological problems. In all fields of intellectual activity it is given to but few men to be both able and willing to think independently and originally. Unfortunately this is as true of biology as of anything else, and per- haps more so. There have been those, however, who have urged that experimental abiogenesis was the great goal of biology, and that it was a field of study in which young men should busy them- selves. Why, then, has there not been more active research in this field? The answer, I think, is two- fold: in the first place there has been the too will- ing acceptance of the dogma already referred to; in the second place there has been a great dearth of ideas about the matter, of sufficient precision to suggest significant experimentation. The attempts at what was miscalled experimental abiogenesis, which were so neatly bowled over by Pasteur, had little if any real bearing upon the problem. What that fight was chiefly about was merely efficient methods of sterilization. There are abundant evidences that the quasi- religious inhibition of efforts at investigation of the transition zone between non-living and living matter INTRODUCTION 15 is rather rapidly disappearing. The work of Lohnis and Enderlein on the life cycles of bacteria; that of Church on autotrophic flagellates; that of d'Herelle and his numerous followers on bacteriophage; and the biochemical studies of Baly and Benjamin Moore and their co-workers, demonstrate that con- siderable breaches are being made in the wall around this forbidden field of research. This wall was constructed with the greatest solidity about the middle of the nineteenth century, and then thought by its builders likely to last for all times. But the cement was not quite up to specifications. So from a biological point of view the present is a propitious time for the appearance of Mrs. Gaskell's original and ingenious speculation. Unless a miracle happens, whereby normal human behavior is tem- porarily altered, this book will doubtless receive its due measure of the violent opposition which every really new idea regularly receives. Its most impor- tant part deals with concepts which lie outside the field of critical competence of most biologists. Furthermore, with a very few exceptions, biolo- gists are entirely unfamiliar with a mode of thought — a point of view — which applies the data and theories of atomic physics to what they as biologists regard as specific, concrete realities, namely the phenomena of life. It is one thing to listen admiringly to the ^^ iiiiiiiiiiiiiiiiiiiinii 16 WHAT 18 LIFE physicist talking about electron orbits and other such remote matters, but quite another to have him advance the idea that these things may have some- thing to do with biology. To both the physicist and the biologist the really real is the familiar. Un- familiarity always tends to breed a certain degree of prejudice and antagonism. But in this particular instance there is less need for concern over the standard and expected opposition to a new idea than is usually the case, for Mrs. Gaskell's hypothesis is capable of experimental test. And by such test, if and when made— and incidentally the making will be no easy task — either its supporters or its oppo- nents will be confuted. The candor and moral cour- age with which she submits her ideas to this test are worthy of all praise. I find no hedging in the book, nor alibis carefully made ready in advance. Mrs. Gaskell has read widely, though by no means exhaustively, in the literature of biology. Any pro- fessional biological reader of the book will note instances where she could have adduced more, and in some cases more pertinent, evidence in support of the particular point under discussion. In a sense all of the specifically biological chapters of the book, which discuss the biological implications and consequences of the theory are, at this stage, pre- mature. If the theory is not, in fact, true, these INTRODUCTION 17 discussions are idle; if it does eventually turn out to be true the discussion of its implications can then take on a degree of confidence and assurance on the biological side which they cannot possibly have now. As ancillary evidence to support the theory I think they have but little weight. But granting all this, Mrs. Gaskell's discussions of various biological prob- lems, particularly that of evolution, have a re- freshing novelty and shrewdness which gives them a value by no means negligible. In some degree she offers us, in this extremely stimulating and original book, that opportunity so rarely achieved, to see ourselves as others see us. Raymond Pearl. Table of Contents INTRODUCTORY 1. On Rating a Theory 23 2. On Presenting My Theory of Life 37 Part One PREPARATORY I. The Organism 47 II. Colloids and Life 60 III. Matter 73 IV. The Atom 82 Part Two THEORY OF LIFE Based on Atomic Physics V. Theory of Life 113 1. General Postulates 2. Particular Assumptions 3. What May Be Ignored 4. What is Meant by a "Critical Concen- tration of Ions" 5. Known Constants and Undetermined Variables 19 32'^iQ 20 WHAT IS LIFE 6. The Setting Up of New Relations 7. Balancing Processes 8. New Properties and Dynamics 9. The Organism 10. The Law of the Structure of Living Matter n. Life 12. Death Part Three PROBLEMS INVOLVED VI. What Elements of Originality are Con- tained in the Theory? 161 VII. The Origin of Species 198 VIII. Why Was This Theory of Life Not Stated Before? 247 IX. On Proof 263 Appendix — Glossary 281 Index 305 What is Life? Introductory Introductory I. On Rating a Theory EVERY new speculation of science, every hy- pothesis or theory, that merits and receives a hearing is subjected to critical examination, and then rated according to well-defined and estab- lished criteria. That hypothesis is an indispensable mental tool, "a legitimate instrument of logic," is not questioned. Mathematical reasoning is legitimate wherever there are "any premises sufficiently precise to make it possible to draw necessary conclusions from them." T. U. Thiele, of the Copenhagen Observatory, in his Theory of Observations, states a fact which is generally recognized and frequently repeated when he says: "It will be found that every applied science, which is well developed, may be divided into two parts, a theoretical (speculative or mathe- matical) part and an empirical (observational) one. Both are absolutely necessary, and the growth of a Note. — In this chapter copious direct quoting seems the best way to em- phasize the fact that the rules for rating a theory are thoroughly established, and nothing remains but to recognize and accept them. 23 jiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiii»^ 24, WHAT IS LIFE science depends very much on their influencing one another and advancing simultaneously." In his presidential address (1920) before the British Medical Association, Sir Thomas Clifford Allbutt, late Regius Professor of Physics in the University of Cambridge, said: "Research, as it is working today, advances from fixed and measured bases; as obser- vation it watches nature's march past; then as experiment it puts events to test under artificial conditions of separation or isolation, and measures their phases. But the laboratory cannot, as nature does, contrive the unexpected; so we must 'gear up our tiny machines to the vast wheel of nature,' and try for a first roughing out of an idea or concept. If we are to select our facts to any considerable pur- pose as crucial, we must first have an idea in our minds; and for this a certain kind of imagination is needed." All of the brilliant modern discoveries have been possible only because venturesome minds have dared to speculate. But the inexorable demand is that every hypothesis must have a firm basis in facts. In no sense may it be a mere unsupported guess. With Sir John Herschel: "To experience we refer, as the only ground of all physical inquiry." There is no such thing as subserving truth in the abstract by the sacrifice of concrete truths. One adverse RATING A THEORY 25 fact is sufficient to disprove the soundness of any hypothesis. Thus, "it is the modern custom now," as observed some years ago by Shaler, "to term the supposition of an explanation a working hy- pothesis, and only to give it the name of theory after a very careful search has shown that all the facts which can be gathered are in accordance with the view." "In its most proper acceptation," ac- cording to J. S. Mill, "theory means the completed result of philosophical induction from experience." A theory that does not account for all the facts which are involved is an inadequate solution. In order to be entirely acceptable, a theory must be both sufficient and necessary. This means that the theory must fully account for the phenomena under consideration, and that they cannot be thus accounted for on any other hypothesis. When thus fully accounted for, the phenomena are (in popular language) said to be "explained." "To 'explain' means," as Hans Driesch defines, "to sub- sume under known concepts, or rules, or laws, or prin- ciples, whether the laws or concepts themselves be 'explained' or not. Explaining, therefore, is always relative: what is elemental, of course, is only to be described, or rather to be stated."^ "A scientific explanation," John Fiske points out, ^ The Science and Philosophy of the Organism, 51. 26 WHAT IS LIFE *'is a hypothesis which admits of verification — it can be either proved or disproved." What constitutes proof in any given case, of course, is determined by the nature of the terms of the speculation. Frequently a speculation concerns a law. In keeping with J. S. Mill's definition of "a law of nature," to discover a law of nature is simply to discover a certain relationship among the units of a given group of phenomena; it is to see a definite arrangement which before had not been observed. When a theory refers to a law, proof of the theory then necessarily means that the relations which the theory afiirms are found to be such as the theory describes. Always, however, direct proof of a theory consists of facts, data of observation and experimentation, to which may be added the logical necessities arising from them. R. D. Carmichael, of the University of Illinois, asserts: "The fundamental scientific activity is that which is expended in the search for truth, in dis- covering and establishing what can be made sure by experiments or by undisputed logical processes con- vincing to all who understand their nature." For, as the late H. A. Bumstead remarked, "when one speaks of modern science, one means, I think, essentially the method of planned and reasoned experiment^ and, with a few sporadic exceptions. RATING A THEORY 27 systematic experimentation was practically unknown until about three hundred and fifty years ago. It marks a very great epoch in human history." A theory, as such, is a thing of merely temporary existence. All speculation — hypothesis and theory — represents effort at interpretation of phenomena. In the course of time, sooner or later, inevitably, the "facts" (data of observation and experimentation) tend to establish the correctness of the original or modified interpretation or they invalidate and dis- credit it. If the facts do not support a hypothesis or a theory, it falls to pieces and is forgotten. This has been the fate of numerous hypotheses and theories. In the event that the facts substantiate the interpretation, again a hypothesis or a theory ceases to exist as such; for proof converts speculation into knowledge, and hypothesis and theory into ac- cepted fact. Thus, today, the nebular hypothesis, as developed by Laplace, continues to command high admiration, but merely as a brilliant speculation; since it has been shown (particularly by Chamberlin and Moul- ton) that pertinent facts and their mathematical necessities discredit it. As Joseph Barrell, of Yale University, says, "A hypothesis, to gain scientific credence, must emerge successful from the test of observed fact and mathe- 28 WHAT IS LIFE matical theory. The nebular hypothesis has not done so. It is on the defensive and has lost standing during the past generation."^ In contrast: Mendeleeff observed periodicity of qualities among the chemical elements, and arranged his periodic table (1871), boldly describing elements then unknown with which to fill gaps in it. The dis- covery by others of the predicted elements furnished superb proof of the correctness of his general inter- pretation (and the interpretation of others) of the phenomena. The progressive and periodic relation- ship of the elements is an established fact on which all later work upon atoms has thrown added light. Theodor Schwann announced his view that plants as well as animals were constituted of cells. Experi- ment soon established the correctness of his specu- lation. Hans Driesch criticises the expression cell-" theory." That organisms are built up of cells is, he explains, "a simple fact of observation, and I therefore can- not agree with the common habit of giving to this plain fact the title of cell-' theory.' There is nothing theoretical in it; and on the other hand, all attempts to conceive the organism as a mere aggregate of cells have proved to be wrong. It is the whole that uses the cells .... or that may not use them: thus there * The Evolution of the Earth and its Inhabitants, 12. BATING A THEORY 29 is nothing like a 'cell-theory,' even in a deeper mean- ing of the word." Relativity teachings, Minkowski's, Lorentz's, and particularly Einstein's (1905 and 1915) are receiving much attention. Some years ago, Dr. Ames of Johns Hopkins University, in speaking about Einstein's theory pointed out that "Einstein's hypotheses are not suggested directly by our sense-experiences, but are statements which seem reasonable; but their sole justification, from a physical sense, will rest in their deductions being in accord with observations."^ Recent observations, it seems, have confirmed the Einstein theory. Some affirm that the theory has been wholly established; others contend that its verification is not complete; while a criticism by Charles Lane Poor in essence amounted to saying that the theory (so far as the interpretation of the movements of the planets is concerned) was neither complete nor necessary. (As is well known, the triple support of the theory has to do with [a] the displacement of the spectral lines of the sun — a deduction from theory which it was first thought had not been verified; [b] the bend- ing of a ray of light passing through the gravitational field of the sun; and [c] the accounting for the motions of the planet Mercury.) * The Constitution of Matter, 236. 30 WHAT 18 LIFE Sometimes a long period of time intervenes be- tween a speculation and its proof or refutation; and that which amounts to a proof of the correct- ness of the interpretation may be secured without the slightest reference to the speculation of long ago. This happened in the case of the atomic theory of electricity. Thales of Miletus, ca. 600 B. C, specu- lated on the discrete nature of electricity. Twenty- five hundred years later (1909) Robert Andrews Millikan isolated and measured the electron. Yet hardly for a moment could one suppose that the re- search work of Millikan, the epoch-making work of J. J. Thomson, and the efforts of Townsend, C. T. R. Wilson, H. A. Wilson, William Crookes, and of Pluecker and Hittorf, were inspired by the specu- lation of Thales. But that electricity is atomic is no longer a speculation, a hypothesis, or a theory, but an established fact. It is plain, then, that a hypothesis or a theory is a thing of merely temporary existence, and that proof converts speculation into knowledge, and theory into accepted fact. "The requisite standard of proof" has been raised in all departments of learning. Today, at least so far as recognized authorities are concerned, it is satis- factorily high: Everywhere there is insistence upon methods that can supply evidence in place of mere RATIN O A THEORY 31 assertion, and in every branch of science there is demand for quantitative measurements. Karl Pear- son, President of the Anthropological Section of the British Association for the Advancement of Science, in an address (1920), said: "I confess myself a firm disciple of Friar Rcger Baccn and of Leonardo da Vinci, and believe that we can really know very little about a phenomenon until we can actually measure it and express its relation to other phenom- ena in quantitative form." Pearson has this to say about the wcrk of the late Wilhelm Wundt, who, holding the chair of philosophy at the University of Leipzig, established the first laboratory of psychology: "Wilhelm Wundt's great work runs to ten volumes. But I also know that in its 5,452 pages there is not a single table of numerical measurements, not a single statement of the quantita- tive association between mental racial characters." T. Clifford Allbutt maintains: "Science consists — as Plato said five centuries be- fore Christ — in measurement." Millikan, whose experimental work on the electron (mentioned before) is a synonym for exquisite exact- ness of measurements, concerning quantitative mea- surements, writes: "It is only upon such a basis, as Pythagoras asserted more than two thousand years ago, that % f 32 WHAT IS LIFE any real scientific treatment of physical phenom- ena is possible. Indeed, from the point of view of that ancient philosopher, the problem of all natural philosophy is to drive out qualitative conceptions and to replace them by quantitative relations. And this point of view has been em- phasized by the far-seeing throughout all the history of physics clear down to the present. One of the greatest of modern physicists. Lord Kelvin, writes: 'When you can measure what you are speaking about and express it in num- bers, you know something about it, and when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. It may be the beginning of knowledge, but you have scarcely in your thought advanced to the stage of a science.' "^ Millikan points out: "There is an interesting and instructive paral- lelism between the histories of the atomic con- ception of matter and the atomic theory of electricity, for in both cases the ideas themselves go back to the very beginnings of the subject. In both cases, too, these ideas remained absolutely sterile until the development of precise quan- titative methods of measurement touched them * The Electron, second edition, 4. RATING A THEORY 33 and gave them fecundity. It took 2000 years for this to happen in the case of the theory of matter and one hundred and fifty years for it to happen in the case of electricity; and no sooner had it happened in the case of both than the two domains hitherto thought of as distinct be- gan to move together and to appear as perhaps but different aspects of one and the same phenom- enon, thus recalling again Thales' ancient be- lief in the essential unity of nature."^ Jacques Loeb asserts: "The epoch-making im- portance of Mendel's work lies in the fact that he, for the first time, gave not a hypothesis, but a theory of heredity, which made it possible to predict the result of hybridization numerically. His work forms the basis for all further work in this field which is of equal theoretical and practical importance."^ In the preface to his volume on tropisms Loeb writes: "It is the aim of this monograph to show that the subject of animal conduct can be treated by the quantitative methods of the physicist, and that these methods lead to the forced movements or tropisms theory of animal conduct, which has only recently been carried to some degree of completion."^ Concerning the application of quantitative meth- * The Electron, second edition, 6. • Dynamics of Living Matter, 185. ' Forced Movements, Tropisms, and Animal Conduct, 7. 34 WHAT IS LIFE ods of measurement to the problem of life, the late Svante Arrhenius said: "We cannot measure life in its various aspects quantitatively as we measure matter and energy To detect means of measur- ing the quantities of life would be a revolutionary discovery which may never be made."* But Jacques Loeb declared that "biology will be scientific only to the extent that it succeeds in reducing life phenomena to quantitative laws."^ The statement that the critical demands of the day in science are satisfactorily high, surely is justified. When, therefore, anyone ventures to offer for ac- ceptance ideas radically different from anything else, and makes bold to call them a theory, it is but meet — provided the work has apparent merit — that the alleged theory be subjected to the severest examina- tion possible. Unless the author has an established reputation in the particular field of inquiry to which the theory belongs, a preliminary rating would con- cern itself with questions such as have to do with the general character of scholarship as reflected in the work and evincing qualification of the author for the work, the value of the authorities cited, methods employed, importance of the subject, and originality. ' Life of the Universe, II, 252. ' The Organism as a Whole, 11. BATING A THEORY 36 This provisional rating is indispensable; since even an author's unquestioned eminence in his own spe- cial field and consequent high reputation, does not always guarantee the value of his theoretical work outside that field. The element of clearness of presentation of a new view is an important factor. The number of per- sons— whether few or many, to whom a new theory makes immediate appeal certainly is not without its direct influence in determining an early or general hearing; yet by no means is the one whose work is on trial permitted to appropriate to himself what Kant said of his Kritik: "The danger is not that of being refuted, but merely that of being misunderstood." If on cursory examination it appears that the general quality of the work warrants it, there follows inquiry into the congruity of the view with the ac- cepted facts of the science or sciences to which the theory is related, and into the legitimacy of the use, or interpretation made of any such facts. There must be found present a twofold agreement: There must be agreement of the views with the facts of science and observation, and agreement between the premises and the conclusions. If no known fact can be shown to be at variance it is conceded that the conclusion deserves to rank as a theory. 36 WHAT IS LIFE The final question is: What, if any, experimental proof of the theory is possible? If the theory is amenable to proof, that is, if it admits of direct experimental test, the fate of the theory always is determined by the outcome of the test. If the result of the test is negative, the best thing that can happen to the theory is speedy ob- livion. If the result is positive, the theory ceases to be mere theory, since proof changes theory into estab- lished fact. II. On Presenting My Theory of Life IT IS with some understanding of the ordinary methods of criticism of a theory that I have ventured to advance a new theory of life. I am also aware of the discouraging and embarrass- ing fact that leading authorities up to the present have taken the position that to try to frame a def- inition of life is a hopeless attempt. One remembers that Sir E. A. Schaefer said: "Everybody knows, or thinks he knows, what life is; at least we are all acquainted with its ordinary, obvious manifestations. It would therefore seem that it should not be difficult to find an exact definition. The quest has, never- theless, baffled the most astute thinkers." One further recalls that Lorande Loss Woodruff, professor of biology at Yale University, writes: "All [biologists] will undoubtedly admit that we are at the present time utterly unable to give an adequate explanation of the fundamental life processes in terms of physics and chemistry. 37 38 WHAT IS LIFE Whether we shall ever be able so to do is unprof- itable to speculate about, though certainly the twentieth century finds relatively few represen- tative scientists who really expect a scientific explanation of life ever to be attained."^ With authoritative pronouncements such as these before one, an attempt to frame a definition of life must appear superlatively foolhardy. It therefore seemed the part of wisdom, and I chose it, to sub- mit my manuscript to a limited number of men pri- vately before seeking a general public hearing for my views. Since my theory of life is built directly upon atomic physics, the first, central and basic re- quirement necessarily is that the views be sanctioned by atomic physics. My question, put to leading specialists in atomic physics, therefore was: "Do you find my views in accord with atomic physics?" To this question I have received affirmative answer from some of the highest authorities in the United States. The granting that the presentation of atomic physics is in conformity with the modern findings, and that my reasoning is valid, is all I ask of any critic. To gain the relative completeness of view of the organism which the theory presents, the facts of physical chemistry and numerous other related facts ^ The Evolution of the Earth and its Inhabitants, 95. ON PRESENTING MY THEORY 39 were carefully taken into account. Quite needless to say, I myself had searched painstakingly to deter- mine, as well as I was able, whether any facts could be found to be adverse to or discordant with my con- clusions. I found none. Nor have any such facts been brought to my attention, though I especially invited criticism on this point. Inasmuch, then, as I am not aware of the exist- ence of any set of facts or single fact at variance with my conclusions, I may be permitted to claim that they deserve to rank as a theory, in the use of the term as previously defined. Making that claim, I of course immediately face the inevitable question concerning proof: "What proof of your theory is possible?" In reply to this question I insist that (as shown in the chapter On Proof) the central proposition of my theory {the general law of the structure of living matter, and the definition of life and of death) is amenable to proof. It is subject to direct quantitative physical laboratory test. And, so far from wishing to evade the question of proof, I devote an entire chapter to its consideration. I do not believe that anyone can insist more strongly that there is need for laboratory proof of the theory than I have insisted, and shall continue to insist until the physical laboratory yields its answer. However, the fact that the theory has not yet been 40 WHAT IS LIFE established by laboratory test, cannot legitimately be used as an objection to the theory, inasmuch as it is one of the outstanding features of the theory that it, for the first time, shows the problem of life to be amenable to laboratory test. Awaiting decisive laboratory test, it may not be forgotten or ignored that it has not been known to happen that a theory, unless it answers to the facts, can serve as a key to the easy solution of various and most diverse difficult problems. The theory concerns a subject that is of universal and transcendent interest — life; and it is approached and discussed from many angles. Therefore it may not be amiss to emphasize the following: 1. The author has built exclusively with or upon the established facts of experiment and observation. 2. Judgment of the merits of the theory, it ob- viously follows, must be based solely on the same sets of facts. No other inquiry has larger philosophical impor- tance than the inquiry concerning life, since the over- shadowing problem of human life necessarily is included in the general problem of life. One may say that the chief value of the inquiry into life indeed lies in its philosophical import, its contribution to philo- sophic thought. For many would say with Karl Pearson: "I am afraid I am a scientific heretic .... ON PRESENTING MY THEORY 41 I do not believe in science for its own sake, I believe only in science for man's sake." The thinker does not and can not accept the cold facts of science about life, without inquiring into the meaning of these facts : What is their relation to the warm, throbbing questions about man's destiny and his "place in nature"? What is the place of "life" in the larger scheme of things of which we have cognizance? Certainly the problem of life directly touches the core of all philosophical inquiry : it indeed is the kernel of the problems of philosophy. As Harald Hoeffding, professor of philosophy at the University of Copenhagen, admits, "it is difficult to draw a sharp line between philosophy and natural science." However, a broad general distinction be- tween science and philosophy is found in that, characteristically, science concerns itself simply with the "how?" and philosophy chiefly with the "why?" of things. It is easy, then, to see that there is a vast difference between a theory and a philosophic thought-scheme. The fact that a theory has profound philosophic import, does not confer upon the one who presents it the privilege of injecting philosophical con- siderations into it; nor does the fact that a theory has profound philosophic import, impose the duty of exhibiting such import. And, plainly, the theory 42 WHAT IS LIFE may not be accepted or rejected because of philo- sophical considerations. Philosophical considerations may not enter. The present effort is a definitely limited one, and expressly concerned merely with a theory — not with philosophy. On presenting an invention or discovery to be patented, it is obligatory upon the inventor specifically to enumerate the points for which he claims original- ity, and to state the uses which his discovery or invention serves. Obviously, such enumeration re- duces the labor of investigating the merits of an alleged discovery. This consideration of expediency has prompted me briefly to enumerate what I conceive to be the ele- ments of originality contained in my theory of life, and its uses as a tool. (Chapter Six.) I have found it easy to do this quite frankly, since I have studied these subjects long enough to be able to take a detached and impersonal view of my work. Besides, there is the overwhelming sense of the im- mensity of the subject and of the pitiful smallness of an individual investigator's capacity for achieve- ment. And in gathering knowledge, I have felt like a child picking up pebbles on a shore strewn with pebbles, remembering — as a comforting (?) thought — that even the immortal Newton felt that ON PRESENTING MY THEORY 43 in his explorations he was merely wandering along the shore of a great ocean, the wide expanse and un- sounded depths of which he was unable to explore. What is Life? PART ONE Preparatory Chapter One The Organism A THEORY of life necessarily is a theory of the living organism, since the research of science into life is concerned exclusively with the concrete. To inquire into life in the abstract is worse than futile. The lowliest organisms are mere unnucleated specks of protoplasm, living matter. The higher unicellular organism consists of protoplasm and a nucleus. All other organisms, from lowest to highest life-form, vegetable and animal, including man, are multi- cellular, each individual having originated in a single cell. Thus the cell is the physiological unit of life. How- ever, though among lowly life-forms like cells are found closely bound together in colonies, one of the higher organisms cannot be described as a colony of like cells. The higher organism is built up of various kinds of cells (tissue, gland, and yet other cells), that moreover serve the organism as a whole. It is well known that during the life of one of the higher 47 WHAT IS LIFE organisms many of its cells die and are replaced by other cells, the process of regeneration in some of the simpler organisms even extending to the replacing of lost parts. As Hans Driesch insists, it is "the whole that uses the cells." Therefore, to describe the in- dividual cells of the higher life-forms does not de- fine the organism. Cells are extremely complex both in chemical con- stitution and in structure, and of great variety, as shown by the vast body of facts of cytology. ^ The absolute specificity of the constitution and functions of the cell is shown in heredity, in which a host of specific traits as well as the general characteristics of the parent form are reproduced — and this in hundreds of thousands of different life-forms. Obviously, the mere fact of the specificity of the germ-cell throws no light whatever on what is the essential nature of the process that determines the successive generations of organisms by means of the germ-cell. The problem of life in its simplest form is the prob- lem of protoplasm. But in the nature of things protoplasm cannot be analyzed. As Woodruff states: "From one point of view it is impossible to analyze protoplasm because the least disturbance of its fun- damental organization results in a cessation of those ^ See Edmund B. Wilson, The Cell in Development and Heredity. THE ORGANISM 49 phenomena characteristic of life, leaving matter in the non-living state before us."^ For this reason physiological chemistry (biochemistry) has the insup- erable diflficulty to contend with that it is restricted to the establishing of the relationship between chemical constitution and reaction and biological function. Nevertheless, Jacques Loeb said: "We must realize that what we call life consists of a series of chemical reactions, which are connected in a catenary way."^ Certainly, a comprehensive theory of life must be a definition of the organism that is absolutely funda- mental. It must differentiate living matter from the non-living world; it must be descriptive of all living beings; and it must apply exclusively to living beings. The fundamental definition of life must provide for all the wide differences as well as for the likenesses that are found from bottom to top in the scale of organisms; it must provide also for the psychic qualities exhibited by the higher organisms, and especially by man; and, finally, it must supply the key to the group of growths classed as neoplasms. The major peculiarities of the organism that dis- tinguish it from the non-living are: 1. Growth. (Synthesizing its own specific mate- rial.) * The Evolution of the Earth and its Inhabitants, 83. * The Mechanistic Conception of Life, 212. 60 WHAT IS LIFE 2. Reproduction. A detached piece of the parent organism (or organisms) is the beginning of the new individual. Reproduction is effected in numerous ways; but from the simple division of the unnucleated speck of protoplasm, a division that is closely re- lated to nutrition and that seems to result merely from redundant growth, through all forms of vege- table and animal life; and whether asexual or sexual or induced through physicochemical means (arti- ficial parthenogenesis), reproduction basically is the same in all. 3. The relative stability of the organism in that autolysis does not take place during life (but does set in immediately after death) — the stability that is characteristic of and synonymous with the living state. The stability that ends with death, and that prompts the questions: What is Life? What is Death? 4. The psychic properties of organisms, not found in the lifeless world, and ranging from mere sen- sation of lowly life-forms to the psychic faculties of man. Besides these major peculiarities of the organism, a number of conspicuous and significant minor peculiarities distinguish the organic from the inor- ganic. Characteristic of organic substances is the heavy molecule, some substances having prodi- THE ORGANISM 51 gious weight. {See Molecule.) Carbon compounds are much less stable than inorganic products toward physical and chemical reagents. Though there is no hard and fast dividing line between polar and non-polar substances, broadly speaking, organic sub- stances are non-polar as distinguished from inor- ganic substances (polar). {See pp. 92, 176.) Certain chemical reactions take place at a lower tempera- ture in the living organism than in the inorganic. Numerous organic compounds contain the same ele- ments in the same proportions, and yet show marked differences of properties. Thus there are 135 com- pounds of one formula. (Isomerism, practically limited to the organic.) Air is an essential factor to nearly all organisms, the only exceptions being a class of bacteria (ana- erobia) that thrive without free oxygen. Take an organism — one of the higher organisms, or say, a man — in full vigor of life and health: if he be de- prived of air for only a few minutes, he dies. All efforts to restore him fail. Life cannot be restored. Jacques Loeb observes: "Death in these, i.e., higher animals, is due to cessations of oxidations, but the surprising fact is that if the oxidations have been interrupted but a few minutes life cannot be restored even by artificial respiration."^ That oxygen is neces- * The Organism as a Whole, 359. 52 WHAT IS LIFE sary to life, was shown by Lavoisier about one hun- dred and fifty years ago, but — as W. Mansfield Clark recently said — "what happens in the cell itself when oxygen is brought to it is as much a mystery as ever." Salts play a large role in life phenomena. Thus, blood contains sodium chlorid and other salts. From sixty -five to eighty per cent of the organism consists of hydrogen and oxygen in the form of water. According to Martin Mendelsohn, of the Uni- versity of Berlin, the enormous stream of fluid sub- stances that circulates through the body is kept in motion by the action of the cells and glands, with the heart "only a subsidiary organ of the circulation system — an unusually large blood vessel." All the elements found in organisms are enumer- ated on pages 100 and 101. Carbon is present in all organic compounds, and organic chemistry is de- scribed as the chemistry of carbon. Compounds that consist of hydrogen and carbon only, the hydrocarbons, are classed in two main divisions, the open-chain (aliphatic, including the organic fats) compounds, and the closed ring, or cyclic, compounds. These two types of the chemical structure of hydrocarbons also are the basis of the classification of all organic compounds. For it is held that all other organic compounds may be de- rived from hydrocarbons by the replacement of TEE ORGANISM 53 hydrogen atoms of hydrocarbons by atoms or groups of atoms (radicals) of other elements. As a convenient theory, then, all organic compounds are regarded as derivations of hydrocarbons. The ideas of structure (pattern of combination) and of substitution (the disappearance of elements and the appearance of other elements or groups of elements) are the simple basic concepts of organic chemistry concerning the formation of the many thousands of complex organic compounds. A highly important group of organic substances are the carbohydrates, (l) sugars, (2) starches and celluloses, compounds of carbon, hydrogen, and oxygen. The molecular formula is known for prac- tically all the sugars. The structure of the molecule of the starches and of the celluloses is unknown. The chemical constitution of sugars and starches and the formation of these carbohydrates in the living plant, of course, are two very different things; the process, which can take place only with the aid of sunlight, involving the living plant, the soil, and the air (carbon dioxide, and nitrogen, since it has been proved that many, if not all, green plants are able to fix atmospheric nitrogen). (Moore, Webster, Mameli and PoUaci.^) * See Carleton Ellis and Alfred A. Wells, The Chemical Action of Ultraviolet Rays, 233. 54 WHAT IS LIFE The photosynthesis of carbohydrates in the Hving plant obviously involves the problem of radiation — one of the most difficult branches of physics. What wave-lengths of light are the effective ones? What does * 'absorption" of the rays mean? How, in what way, does the atom or molecule react to radiation? That sunlight exerts pressure has long been known (Poynting^), but recent research — the Compton ef- fect— would tend to show, recalling Newton's ideas, that radiation is a discrete "corpuscular" quantity. Consideration of all this and of the constitution of the atoms (atomic physics,) then, necessarily enters the problem of the formation of starches and sugars. About eighty -five per cent of the dry material of the human body and a large percentage of the solids of all living matter consists of proteins (proteids). Proteins are classified as protamines, albumins, glob- ulins, histones, glutelins, etc. They contain carbon (about fifty to fifty -five per cent), hydrogen, nitrogen (fifteen to over seventeen per cent), and oxygen. Nearly all also contain a trace of sulphur, and a few contain phosphorus, iron, etc. As a group, proteins are well-characterized, and individual proteins are very specific. However, they are highly complex substances of unknown constitution, derived di- rectly or indirectly from living matter. * The Pressure of Light. THE ORGANISM 65 The chemical substances of which Hving matter is made up are grouped under five heads: 1. Water, and other inorganic materials. 2. Carbohydrates. About one per cent. (Petti- bone.) 3. Proteins. iiVbout fifteen per cent. 4. Fats, and related compounds. About fifteen per cent. 5. Various water soluble compounds. Less than one per cent. Concerning the chemistry of living matter, Jacques Loeb makes the broad statement: "Today everyone who is familiar with the field of chemical biology acknowledges the fact that the chemistry of living matter is not specifically different from the chemistry of the laboratory."^ Again: "No variables are found in the chemical dynamics of living matter which cannot be found also in the chemistry of inanimate nature." Of utmost importance to the organism are the numerous enzymes (ferments). The action of an enzyme is of extreme specificity, but the constitu- tions of enzymes are unknown. Until recently, the most advanced research had succeeded in specific cases in separating an enzyme that in its approx- imation to purity exceeded former preparations nearly ^ Dynamics of Living Matter, \, 56 WHAT IS LIFE a hundredfold. But no enzyme had ever yet been isolated when it was announced in September, 1926, that James B. Summer, assistant professor of biologi- cal chemistry at Cornell Medical College, had suc- ceeded in the isolation and crystallization of urease. Enzymes are produced by the cells of living or- ganisms, and enzyme action belongs to the cardinal functions of living cells. Some recent research de- scribes enzymes as being electrochemical in character (Fodor). The enzymes are organic catalyzers (some enzymes acting hydrolytically), and synthesizers. The study of enzyme action is of foremost interest in connection with the proteins and carbohydrates. Recently, too, it has been urged that the process of fermentation and that of respiration show relation- ship.^ H. von Euler maintains that in respiration the endproduct CO2 results not only from splitting- products of carbohydrates, but that often also the fats (open-chain compounds) and constituents of the complex proteins contribute. The problems of the dynamics of the living or- ganism are intimately bound up with physico- chemical processes — all chemical reactions and all physicochemical processes involve problems of en- ergy (heat, work, etc.). It is well known that all * Hans von Euler, "Enzyme und Co-Enzyme als Ziele und Werkzeuge der chemischen Forschung." Sammlung chemischer und chemisch-technischcr Vor- tr&ge, XXVIII, Heft 6 und 7, 242. THE ORG AN ISM 57 life-processes are accompanied by electrical phe- nomena. Thus, functional change in a tissue, the beat of the heart, every twitch of a muscle, the secretion of a gland, the stirring of life in the seed of a plant, the beginning of life in the hen's Q:gg — all are accompanied by electrical phenomena. Indeed, A. D. Waller's experiments employ a method of galvanometric tests whereby living things such as eggs, leaves, various organs, respond with a "blaze current" and Waller speaks of "electricity as a sign of life." For, the same things when dead do not respond electrically. Much research, covering many years, with which names such as Fere, Veraguth, Tarchanov, Tiger- stedt, and Boris Sidis are connected, has shown that all excitations — sensory, tactile, somatic, etc., — and all human emotion and even abstract thought, cause galvanometric deflections. Various facts, indeed an overwhelming array of facts, indicate that similar laws apply to life-processes and to the inorganic. There is the laboratory syn- thesis of numerous substances that formerly were thought to be products exclusively of life. The dis- covery of the first synthetic vitamin is a recent achievement. An electrical machine, constructed by John Hays Hammond, Jr., has duplicated the helio tropic movements of heliotropic organisms. In 58 WHAT 18 LIFE the Russian physiologist Kuljabko's experiments on the hearts of dead children, carefully prepared salt solutions caused the dead hearts to beat again. This is the more significant since — to quote Dr. Walter H. Gaskell — "the heart's motto, as Ranvier and Kronecker and Meltzer put it, is, 'All or none'; either it will not contract at all, or it will contract to the fullest extent possible at the time." Temperature is an important factor in the meta- bolic and other processes of the organism as it is in inorganic reactions, and variations in temperature directly modify life-processes. This has long been known through the research of J. Sachs, ^ and of others. Askenay^" and A. Kanitz^^ treated of it. Uh- lenhuth has shown that temperature influences the time of the metamorphosis in salamanders. Jacques Loeb and others have shown that changes in the temperature of the air in which fruit-flies (Droso- 'phila) are kept, directly determine a shorter or longer term of life of the flies. By lowering the tem- perature of fruit-flies twenty degrees Loeb prolonged the duration of their life by nine hundred per cent.^^ « "tJber den Einfluss der Lufttemperatur und des Tageslicht auf die stiind- lichen und taglichen Xnderungen des Langenwachstums." Arheiten des Wiirz- berger Institut, 1872, 1. 1" "tJber einige Beziehungen zwischen Wachstum und Temperatur." Be- richte der Botanischen Gesellschaft, VIII (1890). '^ Temperatur und Lebensvorg&nge. " Scientific Monthly, December, 1919. THE ORGANISM 59 And there is the most striking phenomenon of all — artificial parthenogenesis. It was the monu- mental achievement of Jacques Loeb that the eggs of certain life-forms which normally develop only with the aid of a spermatozoon were caused to de- velop by physicochemical means. Also, other un- fertilized eggs have been caused to develop by means of rays — ultra-violet rays in Jacques Loeb's experi- ments, radium rays in G. Bohn's experiments. It is a noteworthy fact that observations made on organisms have led directly to important discoveries or advances in physical science. According to Wil- helm Ostwald, H. J. van't Hoff was led to his con- clusions concerning solutions through a conversation with his colleague, the botanist De Vries. The twitching of the muscles of the leg of a frog (ob- served by Galvani), as Jacques Loeb says, "a mis- understood biological observation, became the germ for the development of electrochemistry." Helmholtz formulated his law of the conservation of energy following his researches into phenomena of heat of the animal body. Chapter Two Colloids and Life No INQUIRY into the constitution of living matter can proceed far without taking account of the outstanding fact that protoplasm resembles a colloid. It is generally asserted that protoplasm is colloidal in character, and indeed the organism as a whole is described as a complex unit colloid system. Thus the colloid chemist, Wolfgang Ostwald, says: "Organisms are merely special instances of colloid systems." A comparison of the lowest life-forms, bacteria, with colloids is interesting. Unquestionably bacteria show the fundamental characteristics of organisms; viz., the synthesizing of their own specific material, and reproduction. As to the close resemblance between colloids and bacteria, we find the following facts: Characteristics of Characteristics of Colloids are: Bacteria are: (a) Brownian movement; Active movement. (6) Electric conduction; The same. Have enor- i.e., they show charges mous energy, and wander to poles; 60 COLLOIDS AND LIFE 61 (c) Specificity; Absolute specificity. {d) Selective adsorption; Staining. {e) Peculiarities of filtra- The same. tion; (/) Some can be evapo- The same is true for bac- rated to dryness and teria.^ then readily redis- solved in water; {g) Easily coagulated; "Probably coagulation kills them in sunlight." The general opinion is as stated by Dr. Rohland : "Bacteria are themselves of a colloidal nature." At the other end of the scale of life one may not ignore facts such as that the human in the third month of intra-uterine existence is a system that consists of ninety -four per cent of water. But here it is evident that to describe the organism as a col- loid system does not solve the difficulties of the or- ganism, even considered merely from the point of view of colloid chemistry; since, for example, to say that the brain is colloidal, so far from solving the prob- lem of the brain, at once raises the question why it is that, though normally the human brain begins to shrink at man's early maturity, his psychic powers continue to increase for many years. ^ 5eeCharlesV.Chapin, "The Air as a Vehicle of Infection." Harvey Lecture, 1913. 62 WHAT IS LIFE However, biologists and physical chemists today are agreed that life is bound up with colloids, and that the physiological life-processes in fact con- stitute a series of colloidal phenomena. Jacques Loeb says: "The material of which living organisms consist is essentially colloidal in its char- acter."^ Thus Martin H. Fischer: "Living matter, whether of plants or animals, and under normal or patho- logical conditions, is chemistry in a colloid matrix."^ Sir E. A. Schaefer states: "For it is becoming every day more apparent that the chemistry and physics of the living organism are essentially the chemistry and physics of nitrogenous colloids. Liv- ing substance or protoplasm always, in fact, takes the form of a colloidal solution." Wolfgang Ostwald writes : "Such particularly com- plicated phenomena as those of life take place in colloid media, and only in such .... The physical and physicochemical conditions necessary for life cannot be more accurately or more concisely summed up than in the words: All life processes take place in a colloid system. The colloid state is the mcnns of integrating biological processes. More correctly expressed, only those structures are considered liv- ^ Dynamics of Living Matter, 1. ^ Translator's Preface to Wo. Ostwald's Handbook of Colloid Chemistry, 6. COLLOIDS AN D LIFE 63 ing which at all times are colloid in composition."* Further, it is the opinion held by all the foremost students of the day who approach the problem of life from the physicochemical point of view, that life on the earth originated in the colloid state. Thus Henry Fairfield Osborn, famous paleontologist: "In the lifeless world matter occurred both in the crys- talloidal and colloidal states. It is in the latter state that life originated."^ In treating of the "Initial Biologic Habitat," the geologist, Thomas Chrowder Chamberlin,^ pictures the early earth as having been rich in colloids. Cer- tainly, the requirements for colloidal formation are very limited. Given the early earth absolutely with- out life, but with continents formed, with water, and the atmosphere — any kind of an atmosphere that could develop into the present atmosphere, heat from the sun — if not direct light, the operation of the known laws of nature, and powerful action necessarily was present, action in the nature of re- duction, or disintegration. Various causes inevitably contributed to the formation of colloid systems, granted only the occasion of a moderate temperature. It is a fact which cannot be doubted that it is im- possible to postulate the existence of the earth in a * Theoretical and Applied Colloid Chemistry, 82, 155. * The Origin and Evolution of Life, 58. 6 The Origin of the Earth, 250-261. 64 WHAT IS LIFE condition with continents formed, or with a sohd crust, without immediately thereafter further pos- tulating the beginning of reduction, or disintegration, of the continental surfaces. This reduction un- doubtedly proceeded in varying degrees and at vary- ing rates, depending upon the sum total of pre- vailing local conditions. At this early stage, tem- perature was a prominent factor. But the immediate and intimate factors in disintegration were the sur- face relations of continent, water — ocean — incipient ocean probably, and inland waters, and atmosphere. These provided at that early time all the various physical surface contacts known; namely: solid — solid; solid — liquid; liquid — liquid; solid — gas; gas — gas; liquid — gas. That disintegration necessarily had to set in is beyond a doubt. And, inevitably, in the course of time colloids, as well as other solutions, had to form. On the importance of colloids in geologic history light is thrown by Raphael Ed. Liesegang, in his volume Geologische Diffusionen. Concerning the formation of colloids on the life- less earth we have, then, two fundamental prop- ositions; namely: (1) we are bound to assume that the formation of colloids, as of other solutions, was inevitable; (2) a definite grouping of elements does COLLOIDS AN D LIFE 66 not enter into the question of the initiation of the process, which necessarily became more and more complex with suflScient time — the years, of which Suess remarks, *'Wliat are a few thousand years in the course of planetary events?"^ But merely to remember Huxley's "Bathybius Haeckeli" saves any one today from calling certain precipitates primitive organisms because they look like organisms, and from investing the colloids of the lifeless earth with the attributes of organisms. As Arthur Isaac Kendall, of the Northwestern Uni- versity Medical School, observes: "Between the lifeless colloid and lowliest known living things there is a mental barrier."^ Many are convinced that there is an actual barrier between non-life and life that cannot be bridged except by means of an outside agency. Thus Svante Arrhenius, whose place in the history of science is secure because of his brilliant work on electrolytic dissociation, especially espoused the ancient idea of panspermia to account for the origin of life on the earth. Some believe that, as Kendall holds, *'it is not beyond the bounds of reason to look confi- dently to a day when science will triumph once again, and produce a colloid matrix in which chemi- cal families are enmeshed." ^ The Face of the Earth, II, 555. ' "Bacteria as Colloids." Colloid Symposium Monographs, II, 195. 66 WHAT IS LIFE Jacques Loeb said: "It is certain that nobody has thus far observed the transformation of dead into Hving matter, and for this reason we cannot form a definite plan for the solution of this problem of transformation." Concerning the transition from the lifeless to life, however the transition is conceived to have been effected — whether by physicochemical processes or through some outside agency, always we are told that colloids were the medium. What, then, are colloids? The following is Wolfgang Ostwald's definition: "Colloids are dispersed systems, in which the diameter of the dispersed particles in typical cases lies between one ten-thousandth and one one-millionth of a millimeter. They are distin- guished experimentally from molecularly dis- persed systems by the fact that they do not dialyze; and from coarse dispersions by the fact that they cannot be analyzed microscopically. Colloids pass through filters readily, while coarse dispersions do not. Transition systems exist be- tween colloids and molecular solutions and be- tween coarse dispersions. The colloid state represents a universally possible state of matter. There is no reason why every substance may not be produced in colloid form. It may be accom- COLLOIDS AN D LIFE 67 plished either through the dispersion of non-dis- persed or coarsely dispersed substances, or through the condensation of molecularly dis- persed systems. To these ends not only chemical but mechanical, electrical and other kinds of energy may be used."^ Concerning the difference between colloids and crys- talloidal solutions, Zsigmondy writes: "According to Bredig solutions of crystalloids and colloids may be distinguished by means of: (a) diffusibility; (6) the work necessary to remove the solvent; (c) electrical migration; {d) coagulation; (e) absorption; (/) irreversible changes of constitution and hys- teresis ; {g) impermeability to other colloids; {h) optical inhomogeneity; (t) electrical formation of sols. *'It is evident from this brief r^sum4 that there are many ways of distinguishing colloids from crystalloids. Notwithstanding this, no sharp line of demarcation can be established, for there are numerous intermediaries between both kinds of solutions. "^° » Theoretical and Applied Colloid Chemistry, 34, 35. ^^ Colloids and the UUramicroscope, 11. 68 WH AT IS LIFE Colloids do not constitute a peculiar kind of matter — as Graham, the founder of modern colloid chemistry perhaps thought in taking account of their dynamic qualities — but only a 'peculiar condition^ or state, of matter (a fact to the establishment of which P. P. von Weimarn especially devoted much labor). Colloids are a peculiar state, or condition, of matter that can be assumed by any substance, even by salts, and that is independent of chemical constitu- tion. Colloids are systems that consist of the "dis- persion medium" (which usually is a liquid, but which may be a gas or a solid) and the "disperse phase." Minute particles of solids, droplets of liquids, bubbles of gases — all may be colloidally dispersed. There are therefor innumerable different kinds of colloids. The simplest systems, of course, are those in which a single element, say silver or gold, is in the colloid state. But colloidal systems are found in most various degrees of complexity. Generally, research on colloids, whether in the arts or in nature has to do with a mixture of colloids; i.e.» not a single kind of particle but two or more varieties of particles are present in colloidal solution. The colloid state is determined by the state of dispersion, the size of the particles, of the disperse phase. This size ranges from 1 to 100 millimicrons. COLLOIDS AN D LIFE 69 The disperse phase of a sol then has enormous sur- face, which gives rise to the various sorption phenom- ena. Some of the properties of colloids vary according to the degree of dispersion. Thus, col- loidal gold changes color with the size of the par- ticle— it may show red or blue or purple. Colloidal solutions are distinguished from true solutions in that the disperse phase of colloids is heterogeneous, giving the Tyndall (optical) effect, instead of homogeneous as in true solutions. A true solution is a molecular solution, whereas the particles in a sol are many times larger than mole- cules. The dispersed particles of a sol show lively movement, the Brownian movement, which is the more violent the smaller the particles. This move- ment is independent of external conditions, and per- sists for months or years — as long as the dispersion medium permits. The movements are due to col- lisions of the molecules of the medium with the particles, and thus the particles, being knocked about, do not settle down, but with reference to gravity rather behave similarly to the molecules of the gases of the air. It is the thermal agitation of the molecules of the medium that causes the molec- ular bombardment of the particles of the disperse phase, the Brownian movement. The laws governing the displacements of these 70 WHAT IS LIFE particles are the same for liquids and gases. The resistance offered by the medium to the movement of a particle-of-a-given-size through it is, of course, much greater in liquids than in gases. A kinetic theory of liquids that answers to the kinetic theory of gases, and Einstein's Brownian movement equa- tion, then, account for the displacements of the particles of the disperse phase of a sol. Research on Brownian movement in gases by R. A. Millikan resulted in the exact evaluation of the gram-molecule, the Avogadro constant N (Loschmidt number L). As for the particles of the disperse phase them- selves— they always acquire electric charges, even in pure water (several and various factors contrib- uting), and wander to poles. That colloids carry electric charges was first shown some thirty years ago (Linder and Picton), and was, as Stieglitz states, "one of the most important discoveries made on colloids."" It appears that the phenomenon of electricity in colloids, that is, of a charged colloid particle, is in a class by itself. Faraday's laws do not apply to col- loids; and there is no known method of determining the amount of the charge carried by an individual particle. Electrokinetic processes are inseparable from colloids. According to Herbert Freundlich, " Qualitative Chemical Analysis, 131. COLLOIDS AND LIFE 71 ''electrical influences are of considerable importance in the study of colloids, but are here of a quite dif- ferent kind from those with which electrochemistry has hitherto chiefly concerned itself. We have to consider here the so-called electrokinetic processes, which do not appear at all in galvanic cells, and only slightly in electrolysis."^^ The colloid particles have a tendency to unite to form larger particles, the larger particles again uniting to form yet larger aggregates, and to precipi- tate, as their electric charges and other conditions and the presence of a small amount of electrolyte permit: There are the phenomena of coagulation, of flocculation, etc. Some conditions, some sols, are reversible, others irreversible. However, many dis- perse systems are very stable. The foregoing is the briefest possible presenta- tion of the leading facts concerning colloids. Ad- vance in colloid chemistry has been rapid within recent years, due to the work of Zsigmondy, Smo- luchowski, The. Svedberg, Wolfgang Pauli, Herbert Freundlich, Perrin, Hatschek, Martin H. Fischer, and many others. However, certainly, since it is not questioned by anyone today that the ultimate interpretation of all physicochemical phenomena as well as of all ^* The Elements of Colloid Chemistry, 75. 72 WHAT IS LIFE other phenomena that involve matter^ must be found in the structure and forces of the ninety-odd atoms of the elements, research that treats of the "mole- cules" of the "dispersion medium" and their "bom- bardment" of the charged "particles" of the "disperse phase" (particles much larger than molecules, chem- ical constitution not necessarily given) and the "surface" of these particles, and of phenomena and relations in terms of these, obviously is a limited inquiry that does not profess to be and is far from being an ultimate analysis. Colloids throw little light on the peculiarities of the organism that distinguish life from non-life; and, as Hans Handovsky says, "it would be foolish to believe that one can solve riddles of life with the aid of colloid chemistry."^^ ^' Leitfcden der Kolloid Chertiie fur Biologen und Mediziner, x. Chapter Three * Matter /'^NE of the most striking changes that modern ^-^ research has wrought, concerns man*s concepts about matter. In its magnitude and its far-reaching significance, this change ranks with the major revolutions of modern thought. First in these great revolutions of modern thought came the change from the Ptolemaic, geocentric, astronomy to the Copernican, heliocentric view. (With the years, the solar system itself, so far as man's ideas of its size and importance in the galaxy of universes is concerned, has shrunk into utter insignificance.) Next geology gave the Western mind an entirely new concept of duration — the un- impeachable record is not of a few thousand years but of millions of years, many millions of years. Next came the sweep of the broad concepts of evolu- tion, the concept of a dynamic and orderly process of development. And now, most recently, there has taken place the great revolution of thought concerning the con- 78 74 WHAT IS LIFE stitution of matter: Whereas, formerly, the atoms of the elements were thought to be ultimate and indivisible units, the atom is now known to be a dynamic system made up of electric units. Today no physicist or up-to-date chemist believes in "the eternity of matter." Moreover, the unity, the essen- tial oneness, of matter and electricity is fully rec- ognized and emphasized. The altered view of the constitution of matter is still so new, and the change in concept so radical, that some confusion in connection with the term "matter" is, perhaps, not surprising. Thus some- times a careless reasoner will argue that because the atoms consist of electrons "there is no matter." But obviously it is crude and meaningless to say "there is no matter," since it is impossible even to write or print the statement without making use of pencil or ink and paper or some other similar mediums, all of which are chemical substances. The term ^' matter^' properly designates everything that can be defined in terms of the chemical atom. Just because the atom has been found to be resolvable into its constituent units, and because, therefore, matter is not now considered to be an eternal and unchanging and primary condition, is then no valid reason for denying the existence of matter. The facts of atomic physics, however, supply MATTER 76 convincing proof that matter is merely a condition^ the condition of positive and negative electrons grouped in the manner and pattern of the elements. For when the constituents of an atom are not in the specific combination that spells the atom, they are ultimate units (positive and negative electrons) with properties of their own. Sometimes, rather loosely, electrons are referred to as "material," because of the "mass" of the elec- tron; though in view of the marked differences between electrons and atoms it is desirable that the terms "matter" and "mass" should not be employed indiscriminately and as exact synonyms. "Mass" is not held by physics to be a measure of extension, or the quantity of matter, but — of electromagnetic origin — a measure of the energy content of a body, relative (changing with change of velocity), and registering as resistance to change (acceleration) of motion. (On the basis of the relativity principle of Einstein, the mass of a body is considered equal to its energy content divided by the square of the veloc- ity of light. E. Madelung, P. P. Ewald, Max Born.) It is an aid to clear thinking to reserve and apply the term "matter" exclusively to the ninety- two chemical elements, the atoms, and their com- pounds. 76 WHAT IS LIFE Concerning the elements, the basic and rudimental concepts are definite and simple. 1. The atoms of the elements are built up of positively charged nuclei and electrons. 2. The elements form a definite and limited series. It is now well known (especially because of Henry Moseley*s work) that the elements form a series from hydrogen, atomic number 1, to uranium, atomic number 92. This series is one of simple arithmetical progression, and represents the basic classification of the elements. The atomic number (as was suggested by Van den Broek^) is determined by the number of free positive unit charges on the nucleus of the atom, every succeeding element add- ing one unit to its number of charges. Not atomic weight, arbitrarily on the basis of oxygen=16, which gives hydrogen =1.0077, he- lium =4, to uranium = 238.2, but atomic number gives the truly basic conception of the progression of the atoms in the natural system of the elements- In the lighter atoms, that is from helium, atomic number 2, atomic weight 4, to calcium, atomic number 20, atomic weight 40.07, half of the atomic weight about equals the atomic number. From cal- cium on to uranium, atomic number 92, atomic weight, 238.2, there is increasing disparity between atomic number and atomic weight. 1 PkysikaliKchr Zeii.tnhriff. XIV, 33, 1913. MATTER 77 Besides the basic arithmetical progression and the increase in atomic weight, the series of the ele- ments shows a periodic recm-rence of similarities of properties, which latter have led to the grouping as found in the periodic table. The periodic table now shows a grouping into eight periods, with the rare gases placed as the first period or (preferably) as the eighth period. However, this does not fully con- vey the periodicity shown by the elements. For on the basis of similarities of properties, the elements also show first a period of two elements, hydrogen and helium, followed by two small periods of eight elements each. Then come larger periods of eighteen elements, with interruptions (the rare earths, from cerium to lutecium) . Finally, there is the great period of thirty -two elements, which is followed by a period of only six more elements, breaking off with uranium. To account for the fact that the series of the ele- ments ends with uranium, when the period of six elements of which uranium is the last, could easily be conceived extended to include more elements, possibly to the rounding out of the period to thirty- two, Sommerfeld suggests that any possible elements that may have followed uranium in this period are now non-existent due to their radioactive decom- position. However that may be, it is certain that the ele- 78 WHAT IS LIFE ments form a definite and limited series. This is the series that properly appropriates the term "matter." 3. The series of the elements is determined by the constitution of the nucleus of the atoms. The atomic number of the elements is determined by the number of free unit charges on the nucleus of the atom; but the number of free unit charges (outer, or orbit, electrons) that an atom can carry is, of course, determined by the constitution of the nucleus of the atom. Thus at once it appears that the nucleus of the atom determines the atom and all its properties. Change in the nucleus of the atom — ejection of alpha particles (helium atoms) or of beta particles (negative electrons) in radioactivity, changes the element. An alpha-ray transformation changes the place of the atom in the periodic table by two units to the left and reduces its weight by four units. A beta-ray transformation, on the other hand, raises the element one unit to the right, without any noticeable change in atomic weight. (Soddy, Fajans.) It is not questioned today that it is the nucleus of the atom that determines the element. 4. The ninety-two atoms, the ninety-two ele- ments, are the building-blocks out of which the entire world of matter is composed. MATTER 79 The existence of matter is, of course, not limited to our own little earth. That the elements found on the earth are also present on the sun, was determined many years ago; and as the result of modern astro- physical research (Saha, Russell, Plaskett, Edding- ton, and others) it is now believed to be almost a certainty that all heavenly bodies contain all of the elements found in the earth. It may be well to remember that, as Aston re- marked, ''starting with our standard bricks, the protons and electrons, we may make, theoretically at least, an infinity of systems by the combination of any number of these. "^ But on the assumption that all stellar bodies are constituted like the earth and our sun, the total of these bodies, then, would represent the amount of matter in existence. A. W. Bickerton, pupil of Tyndall and teacher of Rutherford, points out "the certainty that our vast earth is but a minute speck of cosmic dust, absolutely insignificant in the ocean of space that lies within our own cognizance."^ Forest Ray Moulton, well-known astronomer of the University of Chicago, writes: "Since no other star has been found whose parallax is so great as one second [which corresponds to a distance of about * Isotopes, second edition, 127. ^ The Birth of Worlds and Systems, 127. 80 WHAT IS LIFE 19,000,000,000,000 miles] it follows that the unit sphere whose center is the sun contains no other known sun. The earth compares in volume to this enormous space about as a minute particle only 1/20 of an inch in diameter does to the whole earth. "^ The present-day teaching of some of the leading astronomers concerning the extent of the universe is that embodied in the so-called "island universe'' theory. The Milky Way, the marvelous Galaxy in which the solar system is located, is believed to be an ''island universe." That there are great numbers of "island universes," is the startling new teaching. And each "island universe" is conceived as composed of millions or billions of stars. And yet, incomprehensible as the unknowable magnitude of the number of stars and worlds in space is, the entire universe of "island universes" of them sinks into insignificance when compared with the well-nigh incomparably greater magnitude of stellar distances. Herbert Spencer admitted that "the thought of Space compared with which our immeasureable sidereal system dwindles to a point, is a thought too overwhelming to be dwelt upon."^ That the total amount of matter in space is almost infinitestimal — Lord Kelvin^ thought ultimately * Introduction to Astronomy, 505. ^ Facts and Comments, 292. * Philosophical Magazine, August, 1901 and January, 1902. MATTER 81 really infinitesimal — compared with the volume of space in which it is found, thinkers find the most staggering fact of all. Chapter Four The Atom THE old view that the atoms, the units of the elements, are ultimate and indivisible units necessarily was abandoned with the discovery of X-rays (W. C. Roentgen, 1895) and the discovery of the spontaneous rupture of the atom in radio- activity (Henri Becquerel, 1896). The heaviest known atom, uranium (atomic number 92, atomic weight 238.2) breaks up into a whole series of other elements, of which radium (Mme. and M. Curie, 1898) is one. There came the knowledge that the atoms are built up of positive and negative electrons, and that the atom is a system that consists of a positively charged nucleus which is surrounded by the negative electrons (Sir Ernest Rutherford, 1911). This view of the atom having been established, numerous other now well known facts about the atom came to light: Note. — For an exhaustive treatise on the atoms and mathematical treat- ment of atomic structure, see A. Sommerfeld, Atomic Structure and Spectral Lines, preferably the fourth (German) edition. 82 TH E ATOM 83 A singly charged atom is an atom that has gained or lost one electron; a double charge means the gain or loss of two electrons, and so on. Through the loss of electrons the atom acquires its positive charges; and through the gain of electrons its negative charges. The electropositive elements are the atoms with a tendency to lose electrons; the electronegative elements those with a tendency to gain electrons. Enormous energies are locked up in the atom, as shown in the emission "with explosive violence" of the alpha particle and the beta particle in radio- activity. Some elements are simple, thus hydrogen, helium, carbon, oxygen, and others; some elements (isotopes) consist of atoms that, having the same physical and chemical properties, differ in atomic weight. Thus chlorine, atomic weight 35.46, is an isotope that consists of chlorine atomic weight 35.0 and chlorine atomic weight 37. (Aston.) Ordinary lead has atomic weight 207.2; lead derived from radium, 206.0; and lead derived from thorium, 207.9. All atoms are built on the same general plan. The atom is not an impenetrable structure. The thermal agitation of molecules does not supply sufficient energy to permit the interpenetration of atoms. But an atom endowed with sufficient kinetic energy, readily can enter another atom. Thus an 84. WHAT 18 LIFE atom is not assured sole occupancy of its domain. According to Millikan, "the notion that an atom can appropriate to itself all the space within its boundaries to the exclusion of all other atoms is then altogether exploded . . . . "^ The atom is an exceedingly open and loose struc- ture. It is generally agreed that if the constituents of the atom were packed close together, they would occupy only an infinitesimal part of the volume that is the volume of the atom. As Millikan has shown, a wall of lead at least sixteen feet thick would be re- quired to absorb the "cosmic" rays. In his new cathode tube, Coolidge passes a stream of countless billions of electrons through a window that is made of a nickel plate about 500,000 layers of nickel atoms thick (although only one-half of one-thousandth inch in thickness), and only at rare intervals does an elec- tron collide with an atom in the passage though the 500,000 layers. The alpha particle that is emitted by radium, and that is 8,000 times more massive than an electron, shoots through about 130,000 molecules of air before being stopped. All the evidence forces to the conclusion that, as Millikan says, "the atom itself must consist mostly of 'hole'; in other words, that an atom, like our solar system, must be an ex- ' The Electron, second edition, 194. THE ATOM 86 ceedingly loose structure whose impenetrable por- tions must be extraordinarily minute in comparison with the penetrable portions."^ "Even more open than that of our solar system," another (Aston) describes the structure of the atom. A number of atoms have been stripped of their valence, or outer, electrons by Millikan and Bowen. In these experiments, in succession, 1, 2, 3, 4, and 5 of the outer electrons were stripped from lithium, beryllium, boron, carbon, and nitrogen, atomic numbers 3 to 7.^ Some atoms have been shattered. In 1919, Sir Ernest Rutherford and his assistant, L. B. Loeb, first split the nitrogen atom (by bombarding it with alpha particles).^ Since then it has been shown (by Rutherford, Chadwick and Ellis) that the nuclei of many of the light elements are disinte- grated when struck by very swift alpha particles. In every instance the particle ejected from the atom following an impact of an alpha particle on the nucleus is a single positively charged hydrogen nucleus, or positive electron. The transmutation of elements is a fact of observation, insofar as in the radioactive, uncontrolled (and uncontrollable), changes, an atom through loss of an alpha particle ^Ihid. ^ Physical Review, July, 1924. * E. Rutherford, Philosophical Magazine, XXXVII (1919). / 86 WHAT IS LIFE or a beta particle is transformed into a different element. The remarkable experiments of Ruther- ford in dislodging positive electrons (hydrogen nuclei) from an atom, can only be interpreted as constituting experimental transmutation of one ele- ment into another. Sommerfeld says what becomes of the shattered atom cannot yet be definitely stated in every instance, but probably nitrogen in losing two hydrogen nuclei is changed into carbon. Aston asserts: "There can be no doubt that al- chemical transmutation has been achieved."^ That Dr. Adolf Miethe's experiment (1924) in which he believed mercury had been converted into gold has been discredited by H. H. Sheldon and by other physicists, obviously does not affect Aston's statement. So long as the nucleus of the atom remains intact the element retains its individuality and position, or atomic number, in the series of the elements. Since it has been established that the atom is a system that consists of positively charged nucleus and (negative) electrons, the question has been how to conceive of the grouping of the electrons around the nucleus. In 1913, Niels Bohr, accepting the "nucleus" atom * Isotopes, second edition, 125. TH E ATOM 87 formulated by Rutherford, and calling in the quan- tum theory (Planck), advanced the concept of the atom as a dynamic system in which the negative electrons revolve about the nucleus as the planets do about the sun, but in quantised orbits. Others pic- tured a cubical atom, with the valence electrons fixed in certain equilibrium positions. However, though the cubical atom seemed to harmonize sin- gularly well with the facts of organic chemistry, the idea that the atom possibly may be a system with static valence electrons, has been definitely and com- pletely abandoned. The Bohr theory, that at first described only circular orbits of the one orbital electron of hydro- gen and ionized helium, was greatly expanded by Arnold Sommerfeld, who describes elliptic orbits as well as circular orbits and applies the theory to all the elements. The Bohr-Sommerfeld atom has been found to succeed to a remarkable degree in the interpretation of spectra and the chemical prop- erties of the atoms. Every physicist today holds the atom to be a dynamic system, and the modified Bohr atom is the accepted theory of atomic structure. Millikan says of it: "For the present at least it is truth, and no other theory of atomic structure need be considered until it has shown itself to approach it 88 WHAT 18 LIFE in fertility. I know of no competitor which is as yet even in sight. "^ Thus J. D. Main Smith : "It is the only existing the- ory of the atom which is in conformity with the known facts of atomic structure and spectrum analysis. It must consequently be accepted that the atom of the physicist and the chemist is a dynamic atom, and theories based on static electrons must give place to it, no matter how difficult the conception of the dynamic atom may be for the mechanism of chemical combination."^ It is true that to interpret the valency phenomena of organic chemistry in terms of orbital electrons at first sight offers difficulty. And obviously, if the Bohr-Sommerfeld atom really gives the correct picture of the atom, it eventually must make possible the solution of all problems of valency. In a "Kelvin Lecture," J. H. Jeans observed: "At present the hydrogen atom and the positively-charged helium atom are the only structures which are completely understood, but there can be little doubt that in time the method will unravel for us the secrets of even the most complicated of atomic and molec- ular structures."* Perhaps no fact of science has been more tlior- ' The Electron, second edition, 228. ' Chemistry and Atomic Structure, 163. « Nature, March 7, 1925. TH E ATOM 89 oughly established than the fact that, as first taught by Dalton in 1808, the atom is the unit in chemical changes. The overwhelming proof consists in the demonstration whereby in numerous instances the quantitative analysis of a substance has been followed by the synthetic production of that sub- stance. In the laboratory synthesis of the substance, the atoms may be gathered from various sources and, combined according to the ratios indicated by the analysis, will produce and approximately duplicate the substance. As is well known, there are now many synthetic substances, some of which are of great industrial importance. And the work of chemical analysis and synthesis is going steadily on, ac- cording to no haphazard methods. The valency properties of the atoms are experience facts. Long before the intricacies of atomic structure were even suspected, the "loves and hates" of the atoms were known, and the elements were grouped according to their chemical combining power, or valency, as determined by experimental data. Chem- istry reckons with principal valencies, with residual valency, and with free valency, besides recognizing nulvalent atoms. According to J. D. Main Smith, "Professors Thorpe and Morgan both agree that the time is not yet ripe for the application of general electronic theories to or- 90 WHAT 18 LIFE ganic chemistry." However, there is no other key to valency save the structure of the atom, since all problems of energy involved in valency are bound up with the atom's structure. // the atom really is a planetary system, then all atomic functioning and all relations among the atoms must be described in terms of the atom as a planetary system. Therefore the molecule of the chemist (sharply distinguished from the molecule of physics, a convenient unit of measurement in the kinetic theory of gases) is now pictured as a system of planetary systems. A radical is a cluster of planetary systems. Chemical bonds are referred to the interrelations of the atoms as planetary systems, and to specific valence electrons. All associations and dissociations of atoms, all the manifold changes and properties whatever of all chemical substances that are known to be due to number and manner of combination of atoms, are interpreted in terms of the dynamic planetary atom and its orbital electrons. The radius of an atom is defined by the path of its outermost orbital electron or electrons. An ion (charged atom or molecule) is a planetary system, or a system of planetary systems, that has suffered change through the gain or loss of one or more orbital electrons. This is the general concept. It makes no dif- THE A TOM 91 ference what the chemical constitution of a sub- stance may be, or how compKcated the phenomena that are to be interpreted, or whether the phenomena fall under simple chemistry or any one of the several branches of physical chemistry or under biochem- istry, this is the sole method of interpretation that accords with the accepted view of the atom. It is a curious circumstance that the planetary atom (to which the spectroscopic facts undoubtedly testify, and that interprets well the periodic prop- erties of the elements, and which therefore has been generally accepted) seemingly encounters dif- ficulties in connection with organic chemistry. This impressively serves to emphasize the fact, which chemistry always has had to deal with, that chemical substances fall into two classes, the organic (carbon compounds) and the inorganic. Carbon compounds are much less stable than inorganic substances toward physical and chemical reagents, and require methods of analysis different from those employed for the inorganic. Generally the molecule of or- ganic substances is much heavier than the molecule of inorganic substances. Indeed, the very heavy molecule is one of the chief characteristics of organic substances. The differences between substances that led to their classification as inorganic and organic, are 92 WHAT 18 LIFE found to coincide roughly with the broad classifica- tion of substances as polar and non-polar.^ Gilbert N. Lewis describes them thus: "The very striking differences in properties between the extreme polar and the extreme non- polar types are summarized in the following table . . . . : Polar Non-polar Mobile Immobile Reaction Inert Condensed structure Frame structure Tautomerism Isomerism Electrophiles Non-electrophiles Ionized Not ionized Ionizing solvents Not ionizing solvents High dielectric constant Low dielectric constant Molecular complexes No molecular complexes Association No association Abnormal liquids Normal liquids. "^° These, then, are the various peculiarities and char- acteristics that offer special difficulties and that, all of them — not differences of state caused by tem- perature and pressure conditions — must find their ultimate interpretation in terms of the structure of ' See Gilbert N. Lewis, Journal American Chemical Society, XXXV; and W. Kossel, Annalen der Physik, XLIX. ^^ Journal American Chemical Society, XXXVIII. THE ATOM 93 the atom, in so far, or inasmuch, as the grouping and combination of atoms are involved. But that the facts of organic chemistry, the most compHcated of phenomena and intimately bound up with biochemistry, have been offering great dif- ficulty to the planetary atom, simply means that it takes time for a basic theory that answers to a broad general fact to find complete application. The Bohr-Sommerfeld theory gives the model of the single atom. In the interpretation of the single atom, the series of the atoms, the theory has been eminently successful. Careful scrutiny of the evi- dence by those qualified to judge, and of duly crit- ical temper, has led to the general acceptance of the planetary dynamic atom. However, the dynamics of the atomic system and of each of the individual constituents of the atom are such that when two or more systems unite, inevitably the nuclei of the atoms will exert marked influence on each other, with consequent changes in the positions of the orbital electrons that are involved. Millikan explains: "When atoms unite into molecules, or into solid bodies, these orbits will undoubtedly be very largely readjusted under the mutual influence of the two or more nuclei which are now acting simultaneously upon them."^^ "These ^^ The Electron, second edition, 230. 94 WHAT la LIFE complications register in the spectrum," says J. Franck.^^ Irving Langmuir said that "recent work on spectra has shown that a molecule cannot be set in rotation without changing the configuration of the electron orbits." It is well known that the hydrogen molecule does not show as an exact duplicate of two single hydro- gen atoms, but shows marked changes, in that the orbital electrons belong to both nuclei in common. All orbital changes of the path of a planetary electron are defined in terms of quantum conditions. The modified Bohr theory of the atom, then, pictures the atom as a planetary system in which the planets are negative electrons that revolve about the central body, the nucleus. Max Born tersely says that "the two facts of experience that served as a basis for the considerations that led to the Bohr theory of the atom are: (1) the stability of the atoms; and (2) the validity of the classical mechanics and electrodynamics for macroscopic occurrences."^^ In picturing the atom as a planetary system, several differences are recognized. Thus, whereas there is mutual attraction between the planets as well as between the sun and the planets, the nega- tive electrons while held in their orbits by the 12 Zeitschrift fur Elehtrochemie und Angewandte Physikalische Chemie, Juli, 1925. " Vorlesungen iiber Atommechanik, I, 18 (1925). THE ATOM 95 attraction of the nucleus, repel each other. Again, it is the gravitational mass of the sun that attracts the planets, but in the atoms it is the charge on the nucleus and not its mass that attracts the electrons. Newton's law of gravitation therefore is replaced by Coulomb's law of electrical attraction. Further, whereas the planets of the solar system keep to their several orbits, the electrons of an atom (responding to excitation, and accompanied with marked changes in energy) jump, or fall, from one orbit (or energy level) to another. Again, because it was found that the application of the classical theory led to inconsistencies with the facts of the atom's stability, energy changes in the atom are duly reckoned with on the quantum theory. Thus there has resulted the new mechanics of the atom; and in agreement with the finding that in the series of the elements, beginning with hydrogen, atomic number 1, with each succeeding element one electron is added to the atom, the modified Bohr atom pictures the successive binding of the electrons in the field of the nucleus. In the modified Bohr theory, the requisite number of electrons — the number permitted by the nucleus — are grouped around the nucleus in concentric or- bits, orbits of various types, and in successive "shells," or "energy-levels," the K-shell screening 96 WHAT IS LIFE the nucleus, and successively the L-shell, the M-shell, and other shells. However, it is fully understood, these "shells" are not actual barriers in space in the atom, but mere "energy-levels," since the or- bits of some of the outer electrons penetrate the orbits of inner electrons. Indeed the complexity of interpenetrating orbits is very great in some atoms because of the large number of electrons in each class of orbits and because the orbits occupy all three dimensions of space. As J. D. Main Smith points out: "Only by an extreme license in the use of words can each class of orbit be regarded as constituting an energy level or shell in an atom, for the orbital inter- penetration makes a precise conception of levels im- possible except in the case of truly circular orbits. "^^ Such interpenetration of orbits affects the stability of the atom. Atoms vary greatly in respect to stability. The spectral lines of the atoms, checked by the periodic properties of the atoms, are being inter- preted as necessitating the various orbits with various numbers of electrons in an orbit, and the orbits at various distances and of various forms. Further, the spectral lines are interpreted in terms of wave- lengths and in terms of a quantum analysis. It is a postulate of the Bohr theory that an atom can radi- ate or absorb energy only when an electron is '* Chemistry and Atomic Strvcture, 170. THE ATOM 97 "activated," that is, changes its orbit, or goes from one energy-level to another. This important pro- position has been experimentally verified. Thus Karl Taylor Compton and his collaborators at the Palmer Physical Laboratory (Princeton) found that "the activated states of hydrogen are exactly as he [Bohr] predicted them." "It was similarly found," Dr. Compton said, "that the light of every particular wave-length requires a definite amount of energy for its emission and this energy is the energy of a corresponding activated state of the atom." {See Quantum.) The entire field of exploration of the atom through spectrum analysis has been opened up — from the series of the infra-red (Paschen) to the extreme ultra-voilet (Lyman, Millikan, Bowen, and others) and X-rays {see X-rays). It is, of course, well recognized, and there could be no confusion concerning this fact — at least not in the mind of a physicist — that the Bohr theory of the atom accepts the nucleus of the atom and builds around it in accordance with the evidence of spec- tra and of the properties of the elements. ^^ The exact number of positive and negative elec- trons contained in the nuclei of the atoms is believed 1* As already noted, the "nucleus" atom theory was first advanced by Ruther- ford. In connection with an impenetrable nucleus, however, Lenard's work, too, may not be forgotten. 98 WHAT IS LIFE to be definitely known; but how the nucleus is built up, that is, the manner and pattern of the com- bination of the constituents of the nucleus, is not yet known. Radioactivity gives glimpses. Aston considers it "evident" that "the nuclei of even light elements are very complex structures. "^^ Whatever the manner of the combination, the enormous energy that is displayed in radioactivity is locked up in the nucleus. Some hold that the nucleus is built up of hydro- gen and helium atoms. Nuclei vary greatly in their stability. The close packing of the constituents of the nucleus as compared with the loose structure of the atom, is certain; since the minuteness of the nucleus of the atom as compared with the volume of the atom, has been established. The impenetrability of the nucleus has been shown. The relationship (not the periodicity itself) of properties of the atoms that has led to the classifi- cations of the periodic table of the elements, and the fact that the elements form a series that progresses arithmetically from hydrogen, atomic number 1, to uranium, atomic number 92, indicate relationship of pattern, or the same general manner of combination of the constituents for all nuclei. " Isotopes, second edition, 124. TH E ATOM 99 Sommerfeld, Max Born, and other leading in- vestigators hold that the nucleus is built up ac- cording to the same laws that govern the building-up of the atom. Sommerfeld expresses the conviction that the nuclei are built up of elementary con- stituents according to the same principles of con- struction; namely, according to the rules of the quantum theory, as the atoms are built up from nuclei and electrons. ^^ All are agreed that the nucleus of the atom deter- mines the atom. Irving Langmuir said: "Nearly all of the work on atomic structure has shown that each atom may exist in enormous numbers of different states and that the state of an atom may be modified by nearly every external agent that acts upon it." Again: "Each atom may exist in multitudes of various forms depending on external conditions. The nucleus is the only part of an atom that is absolutely characteristic of it." The atom may undergo various vicissitudes — it may be "excited"; various rays may pass through it and perchance work injury to the structure of the atom; it may lose some of its electrons to other atoms; or it may be "stripped" of electrons; it may share its domain with another atom, etc.; but it *' Atombau und Spektrallinien, vierte Auflage, 217. 100 WHAT IS LIFE will retain its identity so long as the nucleus remains intact. Moreover, an atom that has lost one or more of its outer electrons will recapture electrons as condi- tions permit. Ionization, as observed especially in gases, is temporary, and the effort is to regain the neutral state. But when the nucleus of the atom loses one or more of its constituents, the atom is transmuted and changed irreparably. The nucleus determines the atom. The Bohr theory of the atom accepts the nucleus without having any definite picture to ojfer concerning how the con- stituents of the nucleus are combined in its structure. It is a well-known fact that comparatively few of the ninety-two elements are directly involved in the life-process. The chief chemical constituents of the organism are hydrogen, carbon, nitrogen, and oxygen. The human body practically consists of hydrogen, carbon, nitrogen, oxygen, phosphorus, and calcium, only small amounts of other elements being present. The elements that are found in all organisms are: Atomic number Atomic weight Hydrogen , 1 1.008 Carbon 6 12.00 Nitrogen 7 14.008 Oxygen 8 16.00 THE ATOM 101 Sodium 11 23.00 Magnesium U 24.32 Phosphorus 15 31.04 Sulphur 16 32.07 Chlorine 17 35.46 Potassium 19 39.10 Calcium 20 40.07 Iron 26 55.84 Other elements found in mere traces or large amount in certain organisms are: Atomic number Atomic weight Fluorine 9 19. Aluminium 13 27.1 Silicon 14 28.3 Manganese 25 54.93 Copper 29 63.57 Bromine 35 79.92 Iodine 53 126.92 These may be of very great importance to the organism. Thus, iodine is stored in the thyroid gland; and metamorphosis in tadpoles was induced by feeding them with traces of inorganic iodine. (Swingle. ^^) In its chemical behavior iodine, as well as fluorine and bromine, shows much resemblance to chlorine. Small quantities of cobalt (atomic number 27, ** See Jacques Loeb, Scientific Monthly, December, 1919. 102 WHAT IS LIFE atomic weight 58.97) and nickel (atomic number 28, atomic weight 58.68) have been found present in the human body, especially in the pancreas gland, according to Gabriel Bertaud (director of the biological chemical laboratory of the Pasteur In- stitute, Paris). Among the elements named is the element that is the most abundant on the earth's crust, oxygen. Hydrogen and oxygen as water form more than two-thirds of the earth's surface, and — as mentioned before — constitute from sixty-five to eighty per cent of the organism. The human embryo, it may be recalled, at an early stage of prenatal existence consists of ninety -four per cent water. Nitrogen and oxygen are the chief constituents of the atmosphere — the air (a mixture of gases) con- sists of seventy-eight per cent (in volume) of nitro- gen, and twenty-one per cent of oxygen, and small amounts of argon, helium, and other gases. Carbon, though predominating in organic com- pounds, is relatively rare. Sodium, magnesium, potassium, calcium, and iron, are some of the most abundant of elements. Sodium and chlorine (sodium chlorid) are present in sea-water (the ocean, habitat of numerous life- forms) to the amount of nearly three per cent by weight. /iiiiiiiiiiiiiiimmnitiii THE ATOM 103 The three most abundant elements, oxygen, iron, and calcium, have even atomic number. (That the most abundant elements are of even atomic number, was first pointed out by Harkins, 1917.) All the elements found in organisms in large amounts are some of the lighter elements. Most of them belong to the two small periods of eight elements each, the exceptions being hydrogen (first period of two, or standing alone), and potassium, calcium, and iron (fourth period of eighteen). According to the research of Aston, hydrogen, carbon, nitrogen, oxygen, sodium, phosphorus, and sulphur are simple elements. The rest are isotopes. Sodium, potassium, magnesium, calcium, and carbon are electropositive; nitrogen, phosphorus, oxygen, sulphur, and chlorine, electronegative. Po- tassium shows weak radioactivity. Carbon and nitrogen are among the elements that have been stripped of their outer electrons by Milli- kan. Nitrogen, sodium, and phosphorus have been shattered by Rutherford. Nitrogen, it is well known, is very important to life, although it does not support combustion; and it is especially interesting that the product of nitrogen shattered (with the loss of two hydrogen nuclei) would be carbon. 104 WHAT IS LIFE How the models of the atoms of the electronegative elements oxygen and nitrogen are to be pictured, is not known. Sommerfeld says that at any rate it must be assumed that they are characterized by a certain lack of symmetry in certain of the paths of some of their orbital electrons. Hydrogen is an electropositive element. In the hydrogen atom we have one unit each of the two fundamental building blocks, the two ultimate known constituents and building blocks of all things. (More than a hundred years ago Prout advanced the hy- pothesis that hydrogen itself was the unit of which all other atoms are multiples.) Many believe that electrons, positive and negative electrons, indeed are the two ultimate units. How- ever, science today makes no dogmatic assertions concerning whether electrons are or are not the ulti- mate constituents of things. Ehrenhaft thought he had evidence for the existence of a unit much smaller than the electron. But his experiments were shown to have been faulty, and thus his reasoning invalid. Recently J. J. Thomson sug- gested that the electrons in the atoms may be surrounded by much smaller particles. But assump- tions of the existence of units smaller than the electron are for the present purely speculative. The electron in its two forms is the smallest unit THE ATOM 106 of the existence of which there is actual physical laboratory proof. One each of the two known ultimate electriacl units, then, form the hydrogen atom. Hydrogen al- ways takes the form of a molecule (H2) that can be separated into its atoms only under specific condi- tions: (1) excessively high temperature is required, as in some of Irving Langmuir's work; or, (2) at ordinary temperature the impact of ions (as Nernst says) will split the molecule. Hydrogen, a gas, united with another gas, oxygen, as H2O forms a liquid. This liquid again can assume various familiar states. Hydrogen in other combinations contributes to the formation of solids. Thus it is plain that the various manners of combination of electrical units produce various states as widely difiPerent as possible: 1. Electricity, positive and negative electrons. /the gaseous state; 2. Matter " The Human Body, 33. ^' Archives of Psychology, November, 1913. 192 WHAT IS LIFE To quote Mayo further: "Another important order of facts, which appears to have a significant bearing upon the subject of racial mental differences, is found in connection with the growth and maturing of individuals of different races. Early maturity is known to be related to climate, but it seems also to be related to race." According to my theory, the early physiological maturity of the children of a race, when the early age represents a mean for a sufficiently large number of individuals, indicates, unmistakably and beyond a doubt, that the race has a smaller brain capacity and a lower degree of intelligence, or psychic power, than the races which arrive at physiological maturity later. It hardly would need to be pointed out that the early maturity of a people which is a true index of degree of intelligence, is an unforced normal con- dition. The child marriages of the East Indians are determined by considerations other than fitness for marriage (as attested by engagements between in- fants), and therefore must be classed as without value as an index to the intelligence of the Indians. However, it is a significant fact that though the proud features of the Brahmin are stamped with the consciousness of age-long superiority, yet India con- tributes very little to the intellectual and scientific ELEMENTS OF ORIGINALITY 193 work of the day. The Nobel prize winner, Sir Rabin- dranath Tagore, and the great man of science, Sir Jagadis Chandra Bose, stand out in lonely greatness among the millions of their countrymen. All modifying conditions that abnormally hasten or retard maturity, must be carefully considered. That climate has its effects in determining an earlier or a later maturity is well known, and must be taken into account. Temperature powerfully modifies the rate of progression of chemical reactions. Experi- ments on the fruit-fly (mentioned before) show that a lowered temperature prolongs the life of the fruit- fly. A genuine earlier maturity and mental precocity would appear to belong to the negroid races, accord- ing to the conclusions and testimony of various observers. This fact of the earlier maturity, according to the theory, gives definite value to lighter brain- weight, and testifies to inferior intelligence. If then it should be established on sufficient data that the Negro with his "demonstrably smaller" brain-weight indeed reaches maturity earlier than the white races, that would need to be interpreted as establishing, demonstrating, his inferiority in intelligence, or psychic power. The length of the period of infancy, that is, the length of time it requires to complete the series of 194 WHAT IS LIFE chemical reactions that result in maturity, I repeat* according to my theory, is the index to degree of psychic power, or intelligence, and thus becomes a definite standard for rating the intelligence of races* Measured according to this standard, what is the rating of the ancient Greeks? As Benjamin Kidd said: "During the nineteenth century the opening up of many widely-different branches of research has brought a crowd of workers in various de- partments into close contact with the intellectual life of the Greeks. The unanimity of testimony which comes from these representatives of different spheres of thought as to the high average standard of intellectual development reached by this remarkable people, is very striking. "2^ The Greeks have a galaxy of illustrious names to their credit such as no other country or time can equal. In every department of intellectual activity they produced masters. They reveled in the ele- gancies of thought, in the audacities of speculation, in the profundity of philosophy, and the elusive witchery of poetry. Galton asserts : "The Athenian race is, on the lowest possible ^^ Social Evolution, 252. ELEMENTS OF ORIGINALITY 195 estimate, very nearly two grades higher than our own; that is, about as much as our race is above the African Negro. This estimate, which may seem prodigious to some, is confirmed by the quick intelligence and high culture of the Athenian commonalty, before whom literary works were recited, and works of art exhibited, of a far more severe character than could possibly be appreciated by the average of our race, the caliber of whose intellect is easily gauged by a glance at the contents of a railway bookstall. "^^ It is important to take into account : As it was the Greek nation — a handful of people — that produced the highest intellectual development ever known on earth, so it was Athens which was the flower of this development. Athens was a city in which, Augustus Boeckh says, "in 445 B.C., according to Philochoras .... there were but 14,240 genuine Athenians. Four thousand seven hundred and sixty who had crept into the privileges of citizenship, were on that account, according to Plutarch, sold into slavery, but at all events, they were excluded from the rights of citizenship. Before that time, therefore, there were 19,000 acknowledged as citizens The relation of the free population to the slaves may .... be assumed to have been 27 : 100 or about 1 :4."^* 2' Hereditary Genius, 331. ** The Public Economy of the Athenians, 51, 55. 196 W H AT la LIFE According to the theory, it will have to appear that the Greek people arrived at maturity later, perhaps two or three years later, than present white peoples do, in order to prove that their dazzling intellectual achievements were due to greater "brain capacity" and higher psychic power. Unless it can be shown that the Greeks were distinguished by a longer period of infancy than ours, their supposed superiority must be attributed merely to an un- equaled devotion to education and culture. XXVII. The theory for the first time shows that the problem of life itself is, not indirectly but directly, a physical laboratory problem. Experimentally to establish the general law of the structure of living matter, and the fact of life as a quantity (given by the theory), falls to the lot of the physicist. It is well known that the research of biophysics consists in the study of the biological effects of radium, and other rays; the measuring of the pene- tration of certain rays into protoplasm; determining the "absorption" and physiological action of rays in protoplasm, etc. (Most of the work in biophysics is done in connection with cancer research.) However, the proposition: Life is a quantity ^ a quantity different from the quantity that is the body, but constituted of the same, that is, like, elementary ELEMENTS OP ORIGINALITY 197 units that constitute matter — this proposition does not enter any of the experiments in biophysics which have been made up to the present. It would appear, then, that the theory (1) states the general law of the structure of living matter; (2) yields the definition (a) of life, and (b) of death; (3) elucidates obscure phenomena; (4) indicates new methods of approach to various problems; (5) directly leads to new laboratory research; (6) necessitates the rejection of the current theory of descent; and (7) subverts the present teaching of science about the soul. Chapter Seven The Origin of Species As EVERYONE knows, Darwin's Origin of k. Species (1859) constitutes the great landmark in the history of the concept of the evolution of species. In an address delivered at the University of Freiburg, on the occasion of the centenary of Darwin (1909), August Weismann said that Darwin's Origin of Species "raised a conflagration like lightning in a full barn." The concept of the evolution of species had been a prolific idea long before Darwin; indeed, the con- cept was a familiar one to the ancient Greeks. Weis- mann reminded his hearers : "You know that Darwin was not the only one, and was not even the first, to whom the idea of evolution occurred." A writer in the Biologisches Zentralblatty J. H. F. Kohlbruegge, asked: "Was Darwin an original genius?" and adduced about two hundred names to prove a nega- tive answer correct.^ ' Biologisches Zentralblatt, XXXV, Februar, 1915. 198 ORIGIN OF SPECIES 199 Aristotle (384-322 B.C.) was perhaps the first to teach descent, Empedocles (ca. 490-430 B.C.) earher having taught succession from lower to higher forms of life. As the real founder of the modern theory of the evolution of species one must name Jean Baptiste Pierre Lamarck (1744-1829); while Alfred Russell Wallace is known as the "co-discoverer" with Darwin of the theory. Weismann holds that "the credit for thus establishing the theory of evolution is shared with Charles Darwin only by his contemporary, Alfred Russell Wallace." Yet Charles Darwin, Her- bert Spencer, and Ernst Haeckel form the great picturesque trio of the theory of descent — that dominating theory of the nineteenth century. The late William Bateson pointed out that "the first full conception of the significance of variation we owe to Darwin." Evolutionary views held before the time of Darwin are presented by Henry Fairfield Osborn in his volume. From the Greeks to Darwin. A study of the evolutionary ideas of the Greeks is also found in an address by E. Zeller, delivered (1878) before the Akademie der Wissenschaften (Berlin), *'Uber die griechischen V or ganger Darwins'"^ The general theory of descent always has involved the question of man's descent; since the problem of ^ Abhandlungen der koniglichen Akademie der Wissenschaften, Berlin, 1878. 200 WHAT IS LIFE human life, it appears, cannot be isolated from the general problem of life, as, for example, the extreme followers of Descartes attempted to do. A very near "blood-relationship" between man and the apes has been established by certain reaction tests (made by Uhlenhuth, by Nuttall and others). Hugh K. Berkeley, of the University of California, in a paper on "The impossibility of differentiation between monkey blood and human blood," says: "It would seem impossible, then, to utilize antisera from the lower monkeys for the forensic differentia- tion of human from monkey serum. "^ The manifest resemblance between man and the anthropoids served as sufficient ground in the sixties of the last century, the early days of the modern doctrine of descent, for the announcement that man evolved from the orang-outang. Darwin taught that "the Simiidae then branched off into two great stems, the New and the Old World monkeys; and from the latter, at a remote period, man, the wonder and glory of the universe pro- ceeded." Today opinion is divided. Many still believe in the direct close relationship between man and the existing apes. Of these some — Felix von Luschan, Klaatsch, and others — incline to the belief that in a more or ' University of California Publications, II, 12. ORIGIN OF SPECIES 201 less direct line of descent the white race is related to the chimpanzee, with its white face; the negro to the gorilla, having a black face; and the Mongolian to the orang. Others hold the opinion that man evolved from an ape-like progenitor, though not from any ape now in existence. Yet others insist that man and the anthropoids are descended from a common stock. According to one interpretation, the several apes have retrograded from the common stock in various degrees. Richard Swann Lull, director of the Pea- body Museum, Yale University, holds this view. According to Lull "all of these apes, the orang, chimpanzee, and gorilla, are degenerating from the higher condition of their common ancestor with mankind, the chimpanzee least, the gorilla most of all."^ The most critical students of the problem — Henry Fairfield Osborn and others — are inclined to push the assumed common ancestry of man and ape back to an indefinitely remote period. Gustav Fritsch, eminent anthropologist, deplores what he calls "the still widely made untenable assertion: 'Man is descended from the ape'.** Duckworth holds: "We must conclude that the existing anthropoid apes, constituted as they now * Evolution of the Earth and its Inhabitants, 140. 202 WHAT IS LIFE are, did not figure in the ancestral history of man."^ For on closer examination there is found lack of similarity between man and apes where, on the theory of descent or of near relationship, similarity should be found. Thus, for example: It is a remark- able fact that there is utter dissimilarity between the arrangement of the growth of hair of the human head and the head of apes.^ Again: The hand — next to man's superior brain, his long infancy and his erect carriage, his most characteristically human possession — resembles the hand of the ape, yet a comparison of finger-prints and hand-prints of man and ape has shown surprising dissimilarity between the human hand and the ape- hand. As everyone knows, the finger-tips of the human hand are marked with whorls. Experimenters found that the monkey -hand has the whorls on the mounds, and the finger-tips are marked with straight lines. To say that the general theory of descent, including of course man's descent, today is commonly accepted by the world of science is but to state a well-known fact. One therefore might suppose that the foremost students of the problem hold the opinion that the ^ Morphology and Anthropology, I, 238. • See Gustav Fritsch, "Die Anthropoiden und die Abstammung des Menschen," Zeitschrift fiir Ethnologie, L, 1. ORIGIN OF SPECIES 203 doctrine of descent in the form of Darwinism rests upon secure bases. However, such is not the case. The entire theory of descent has been beset with formidable diflficulties from the first; and these diffi- culties have not been overcome. The chief difficulties in the way of the theory have been (1) paleontological difficulties; (2) the evident fixity of species; and (3) the crudity of the conceptions on which the theory rests. 1. The paleontological difficulties are (a) the great gaps which exist in the geological record; and (6) the suddenness of the appearance of new and higher life-forms without record of intermediate forms to connect them with the earlier forms. The older geologists spoke freely of the extinction of life, and the appearance of new species. As an eminent geologist of today, Charles Schuchert, of Yale, says: "Because of the long-enduring intervals of lost record, the subsequent faunas are not only very different, but appear as if suddenly or at least quickly evolved."^ Eduard Suess, famous author of the monumental work, The Face of the Earth (English translation from the German original, 1904-1908), states: "Whole groups, entire animal and vegetable populations, or, if I may so express myself, complete economic unities » A Text-Book of Geology, 453. 204. WHAT IS LIFE of Nature appear together, and together disappear."^ Suess, of course, like all other geologists of today, believes in the unbroken ascent, or evolution, of life, but he testifies to "... . the simultaneous appear- ance and disappearance over vast areas of whole communities, of whole economic unities; the same phenomenon which Heer long ago happily designated 'the periodical recoinage of organisms'."^ The older geologists, interpreting the evidence of the geologic record unhampered by any difficulty of theory, formed their estimate of the plural origins of life. Creation was the method assumed. Hence they were not concerned about the fact that these great geological epochs of appearance, disappearance, and new appearance of life would seem to indicate plural origins. They had only to say what they saw, without having to reconcile it with any theory. This represents the general position of pre-Dar- winian geologists; though some geologists indeed occupied themselves much with the problem of life as related to evolution. With Suess: "Let us glance over the period from 1849 to 1859. The doctrine of successive creations reigns everywhere. Each larger subdivision of the geological series is considered to denote an act of special creation."^" » The Face of the Earth, I, 11. 8 Ibid., 13. '» Ibid., 8. ORIGIN OF SPECIES 205 The older geologists fully recognized the magnitude and importance of the great continental and other changes suffered by the earth — cataclysmic, cata- strophic, in character, as they described them. But after Darwin's book created its great furore and (championed by Fritz Mueller, and Haeckel — Haeckel foremost, with his fiery enthusiasm and his "life-tree" — and Huxley and Weismann) gained general recognition and wide acceptance for the theory of descent, including man's descent, the geologists showed a tendency to minimize or ignore the greatness of the several successive periods in the earth's history that over wide areas were destructive and inhibitive to land-life, the intervals that were followed by the comparatively sudden appearance of higher and ever more varied life-forms. Of late these periods of convulsions have been re- ceiving due attention, at least by some authorities. The vicissitudes suffered by the earth are vividly set forth by Pirsson and Schuchert^^ and by Suess.^^ Of course, the fact that geology has not disclosed a complete life-series, is only a negative difficulty. All who hold the theory of descent believe that a complete geologic record would disclose an unbroken line of descent. . 11 A Text-Bool: of Geology, 450. 12 The Face of the Earth, I. 206 WE AT IS LIFE Darwin himself pointed out: "But just in proportion as this process of ex- termination had acted on an enormous scale, so must the number of intermediate varieties, which have formerly existed on the earth, be truly enormous. Why then is not every geologi- cal formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic change, and this perhaps is the most obvious and gravest objection which can be urged against my theory. The explanation lies, so I believe, in the extreme imperfection of the geological record. "^^ But so far as the theory of descent is concerned, the record of geology is as unsatisfactory today as it was when Darwin wrote. Suess admitted some years ago: "The fact remains that we do not find species varying gradually within the limits of single families or genera, and at different times. "^"^ (Surely, no one would venture to suggest that the great geolo- gist forgot the ^^Formenreihe" of Waagen^^ and the change in the toes of the horse. ^*') 2. The evident fixity of species, the evident ob- served persistence of type, always has been a diffi- " The Origin of Species, Chapters IX and XII. 1* The Face of the Earth, I, 13. " Die Formenreihe des Ammonites suhradiatiis. 1' See Henry Fairfield Osborn, The Origin and Evolution of Life, 266-269. ORIGIN OF SPECIES 207 culty to the current theory of descent. Fixity of type of certain species, geological evidence shows, has persisted through millions of years. Henry Fairfield Osborn writes: "Of the eighteen great orders of reptiles which evolved on land, in the sea, and in the air, during the long Reptilian Era of 12,000,000 years only five orders survive today; namely, the turtles (Testudijiata), tuateras {Rhynchocophalia) , lizard {Lacertilia), and crocodiles {Crocodilia). "The evolution of the members of these five surviving orders has either been extremely slow or entirely arrested during the 3,000,000 years which are generally assigned to Tertiary time; we can distinguish only by relatively minor changes the turtles and crocodiles of the base of the Tertiary from those living today. In other words, during this period of 3,000,000 years the entire plant world, the invertebrate world, the fish, the amphibian, and the reptilian worlds have all remained as relatively balanced, static, unchanged or persistent types."^^ According to Jacques Loeb "the constancy of species, i.e., the permanence of specificity may there- fore be considered as established as far back as two or possibly two hundred millions of years. The " The Origin and Evolution of Life, 231. 208 WH AT IS LIFE definiteness and constancy of each species must be determined by something equally definite and con- stant in the egg, since in the latter the species is already fixed irrevocably."^^ Bateson expressed the following opinion: "With- out presuming to declare what future research only can reveal, I anticipate that, when variation has been properly examined .... the result will render the natural definiteness of species increasingly appar- ent."i9 Since the authorities that have been quoted are numbered among the staunchest adherents to the doctrine of evolution, it is plain that the fact of the observed specificity has been soberly stated. The experimental research that has been done on cross-breeding, etc., does not offset or nullify the difficulty that in geologic time certain species have remained constant for millions of years. 3. The greatest difficulty of the theory of descent is that it is built on insecure bases and superficial reasoning. {See p. 249.) On close examination, the bases turn out to be exceedingly flimsy and insecure; consisting still, as they do, of the same vague generalizations, super- ficial inquiries, and loose reasoning from indefinite '* The Organism as a Whole, 43. ^' Problems oj Genetics, 21. ORIGIN OF SPECIES 209 premises, which vitiated the early treatment of the problem of heredity and variation and the en- tire problem of the evolution of species as a whole. The most critical students of the problems that are involved in the doctrine of descent, are extreme- ly dissatisfied with the alleged evidence on which it rests. As Bateson states: "The advance has been from many sides. Something has come from the work of systematists, something from cultural experiments, something from the direct study of variation as it appears in nature, but progress is especially due to experimental investigation of heredity. From all these lines of inquiry we get the same answer; that what the naturalists of fifty years ago regarded as variation is not one phenomenon but many, and that what they would have adduced as evidence against the definiteness of species may not in fact be capable of this construction at all."^° Concerning the arguments employed in treating of the problem, Bateson writes: "A vast assemblage of miscellaneous facts could formerly be adduced as seemingly com- parable illustrations of the phenomenon 'varia- tion.' Time has shown this mass of evidence to be capable of analysis. The transformation of *" Problems of Genetics, 15. 210 WHAT IS LIFE masses of population by imperceptible steps guided by selection, is, as most of us now see, so inapplicable to the facts, whether of variation or of specificity, that we can only marvel both at the want of penetration displayed by the ad- vocates of such a proposition, and at the forensic skill by which it was made to appear acceptable even for a time. In place of this doctrine we have little teaching of a positive kind to offer."^^ It was the early assumption on inadequate evi- dence that a series of characters was successively evolved. Perplexing difficulty attends the later un- certainty of interpretation regarding the successive or simultaneous and independent evolution of such characters. (According to Eduard Seler, of the Zeitschrift fiir Ethnologie, the problem is receiving much attention. Felix von Luschan,^^ and others treat of it.) A very great difficulty which attends the current theory of descent, a difficulty which is receiving wide and growing recognition, is the vagueness and crude- ness of the conceptions of the causes and factors of heredity and variation which were current sixty years ago, and for which the later literature of the subject offers no satisfactory substitutes. For today, " Problems of Genetics, 14, 248. ^^ ZusammenJidnge und Konvergenz. ORIGIN OF SPECIES 211 when the question of descent takes the form of inquiry into the causes and factors of heredity and variation, those best informed — after a half -century of Darwin- ism— profess only ignorance. The utter unsatisfactoriness of the general situa- tion in evolutionary inquiry appears in especially strong light when the indefiniteness and vagueness of it all is compared with the definiteness and exact- ness of the work done in chemistry and physics. That life-processes are characterized by the same precision of relations that always obtains in chemistry and physics is clearly indicated by specific lines of experi- mental research in botany and biology — cytology, heredity-investigations of the kind inaugurated by Mendel, and pursued by Raymond Pearl, Thomas Hunt Morgan and others, and experiments on arti- ficial parthenogenesis (J. Loeb's and others'). To quote Bateson again: "As to almost all the essential features, whether of cause or mode, by which specific diversity has become what we perceive it to be, we have to confess an ignorance nearly total. .... When .... we contemplate the problem of evolution at large, the hope at the present time of constructing even a mental picture of that process grows weak almost to the point of vanish- ing. We are left wondering that so lately men 212 WHAT IS LIFE in general, whether scientific or lay, were so easily satisfied. Our satisfaction, as we now see, was chiefly founded on ignorance. "^^ Henry Fairfield Osborn admits: "We have no scientific explanation for those processes of develop- ment from within, which Bergson has termed 'revolution creatricey' and for which Driesch has abandoned a natural explanation and assumed the existence of an entelechy, that is, an internal perfect- ing influence."^* In passing, it must be noted: (1) The difficulties that beset the current theory of descent have been stated in the exact words of the men who are quoted; there has been no garbling or recasting of statements. (2) The criticisms are by representative leaders in science whose findings command respect. (3) These men are firmly convinced that evolution is a fact. Some persons have understood these criticisms and similar expressions of extreme dissatisfaction with the current theory of descent (criticism within the ranks of science, by some of the ablest men of science) to mean that the general doctrine of evolution may be rejected. This, however, is an erroneous con- clusion. It is not necessary here to adduce the various '' Problems of Genetics, 248, 97. *' The Origin and Evolution of Life, x. ORIGIN OF SPECIES 213 reasons why men of science are almost as one man in their acceptance of the doctrine of evolution; but it is a fact that perhaps never before in the history of human thought has there been more complete unan- imity of opinion on a debated question than the unanimity of men of science concerning the general idea of evolution. Galilei may have yielded to pressure and recanted his costly truth, but it is im- possible for a man of science of today to renounce his belief in evolution. This makes it plain that the problem of the origin of species is recognized as a special problem in evo- lution. Yet, while singling it out as a special problem, it may not be ignored that it is indeed the core of the problem of organic evolution. Therefore it is small wonder that the opponents of evolution consider the honest admissions of dissatisfaction with the theory of descent as extremely damaging to the entire doctrine of evolution. The current theory of the origin of species, as everyone knows, is an effort to account for the suc- cessive appearance of higher and higher forms of life during geologic time. It teaches that all existing life-forms have descended in an unbroken line from the first and lowliest form or forms of life on the early earth. With the origin of life the theory is not con- cerned. The problem of the theory is how to account 214 WHAT IS LIFE for the manifest variety and the observed specificity. As everyone now recognizes it to be, the problem of the origin of species primarily is the problem of heredity, which involves the problems of specificity and of variation. Until recent years, the theory of organic evolution was only a quasi-scientific one; certainly, there was little inquiry into the actual life-process. But the problem of the origin of species undoubtedly is first of all a problem of life, a part of the general problem of life. Without being able to account for the fundamental life-process, to try to account for the ascent of life, for the observed speci- ficity and for variety, necessarily is a pitifully futile and hopeless effort. It would seem obvious that a knowledge of the process of the reproduction of life-forms is essential to an intelligent inquiry into the causes and factors of heredity. A brief review of the general facts about reproduction, therefore, may not be omitted. Though there still is much to learn, today science can at least boast that it has a fair knowledge of the process of reproduction. The study of the reproduction of life-forms is an elaborate study. Reproduction takes place in many different ways. The vegetable kingdom possesses a variety of methods for reproducing forms. In the animal kingdom the methods of reproduction range ORIGIN OF SPECIES 215 from the simple division of the apparently structure- less speck of protoplasm, and next the cleavage of the nuclear unicellular organism, through numerous methods, up to the birth of the mammalian offspring, and to the coming of the human child into the home lovingly prepared for its advent. However, as mentioned before (p. 50), funda- mentally all methods and forms of reproduction are alike in that they represent the detachment of a part, or particle, of the parent organism, or of two organ- isms, which, given food supply and favorable con- ditions, grows into the likeness of the parent form. The close relationship that exists between nutrition and reproduction is well known to all students of the multitudinous phenomena of the reproduction of organisms. Reproduction is asexual or sexual. In the lowest forms of life, reproduction is asexual. In some forms asexual and sexual generation alternate. In the higher animals reproduction is sexual. Parthenogenesis — in the strict meaning of the word — seems to be entirely out of the question among organisms as high as the vertebrates. True, Dr. Leo Loeb (whose cultures of cells in vitro have been mentioned) found peculiar structures in the ovaries of guinea-pigs, which structures, he said, "must be interpreted as embryos developing parthenogeneti- 216 WHAT 18 LIFE cally within the ovary of the guinea-pig. "^^ Leo Loeb expressed the opinion that his observations "make it extremely probable that in a relatively large pro- portion of mammalian animals a spontaneous par- thenogenetic development of ova takes place at some period during the life of the animal. "^^ But this of course does not invalidate the statement that, strictly speaking, parthenogenesis seems to be out of the question among the higher organisms. And the general statement still holds though parthenogenesis has been caused in so high a form as the frog — by merely puncturing the frog's egg (first by Guyer, also by Jacques Loeb, and others) ; for normally the egg of the frog develops only when a spermatozoon enters. As Jacques Loeb observed: "The reader knows that the eggs of the overwhelming majority of animals cannot develop unless a spermatozoon enters them."" The differentiation of sex begins near the bottom of the scale of life. However, examples of inter- sexuality, that is, "the occurrence of examples inter- mediate between the normal male and female of the species" are cited from invertebrates (Dr. R. de la " Journal of Medical Research, 1901. '* Proceedings of the American Philosophical Society, Philadelphia, 1911. *" The Mechanistic Conception of Life, 200. ORIGIN OF SPECIES 217 Vaulx).^^ Also, Janda experimented upon a hermaph- roditic worm, and found that "in a hermaphrodite both types of sex organs can be produced from body cells or from latent buds resembling body cells. "^^ The late E. A. Minchin said: "The vital processes exhibited by the cell indicate a complexity and a minuteness in the details of its mechanism which transcends our comprehension and baffles the human imagina- tion, to the same extent as do the immensities of the stellar universe. If such language seems hyperbolic, it is but necessary to reflect on some of the established discoveries of cytology, such as the extraordinary degree of complication attained in the process of division of the nucleus by karyokinesis, or the bewildering series of events that take place in the nuclei of germ cells in the processes of maturation and fertilization. Such examples of cell-activity give us, as it were, a glimpse into the workshop of life and teach us that the subtlety and intricacy of the cell-micro- cosm can scarcely be exaggerated."^*^ Concerning germ-cells, Edmund B. Wilson ex- plains : "In the lowest forms, such as the unicellular 28 Nature, July 8, 1922. 2' Jacques Loeb, The Organism as a Whole, 220. '" American Naturalist, 1916. 218 WHAT IS LIFE algae, the conjugating cells are, in a morpho- logical sense, precisely equivalent As we rise in the scale, the conjugating cells diverge more and more, until in the higher plants and animals they differ widely not only in form and size, but also in their internal structure, and to such an extent that they are no longer equivalent either morphologically or physiologically."^^ Again: In the higher life-forms "the gametes differ widely in form and function, the macro- gamete or ovum being a very large, quiescent cell, while the microgamete or sperm is a very minute and usually motile cell, typically pro- vided with one or more flagella or cilia. "^^ Jacques Loeb says that "only in respect to the chromosome constitution are egg and sperm alike, while they differ enormously in regard to the mass of protoplasm they carry. "^^ The spermatozoa are naked cells, that is, cells with- out membrane or protective covering. They are detached glandular cells, rod-shaped, motile, ciliated, of which each drop of seminal fluid may contain millions. Of the millions of spermatozoa that press around the ovum only one enters the egg and effects fertiliza- '1 The Cell, second edition, 229. '2 The Cell in Development and Heredity (1925), 256. '' The Organism as a Whole, 251. ORIGIN OF SPECIES 219 tion. (See p. 183 for the conception of the germ-cells supplied by my theory.) Experimental biology de- scribes fertilization as the activation of the "ripe" egg, that consists in the initiation of adequate chemi- cal changes in the egg. (Concerning "ripe," see p. 225.) In sexual generation both parents provide each a single cell. Any variation from this — as, for example, one egg giving rise to two individuals — is an ex- ception. "Contact of the sperm," as Edmund B. Wilson describes, "calls forth a powerful and almost instan- taneous reaction by the egg that is responsible not only for entrance of the sperm, but also for many other changes in the ooplasm. "^^ The fusion of the ovum and the sperm-cell is a process which involves a number of interesting and important phases. Fertilization, impregnation, conception, having taken place, immediately the process of cell division commences. With the first division of the impreg- nated ovum, the growth and development of the new individual is begun. A number of biologists obtained some very interest- ing results experimenting on fertilized eggs at the two-cell stage. Jacques Loeb put the eggs of the sea- ^* The Cell in Development and Heredity (1925), 409. 220 WHAT 18 LIFE urchin soon after fertilization into a solution which differed in specific points from sea-water, and found that "when the eggs are allowed to segment in such a solution the first two cleavage cells are as a rule in a large percentage of cases — often as many as ninety per cent — separated from each other, and when the eggs are put into normal sea-water (about twenty minutes after the cell division) each cell develops into a normal embryo. "^^ Experimenting upon eggs of the frog, it was found — first by Hans Driesch — that if the first two cells of a dividing egg are sepa- rated, each cell develops into a whole embryo of half size. Driesch also found that by shaking a sea- urchin's egg in the four-cell stage, the four cells may be separated, and each one may develop into a com- plete embryo, "which only differs in size from the normal embryo." In Jacques Loeb's words: "Roux destroyed one of the two first cells of a (fertilized) frog's egg with a hot needle and found that as a rule the surviving cell developed into only a half embryo. "^^ Again Loeb's words: T. H. Morgan "destroyed one-half of the egg (fertilized frog's e^g) after the first segmentation and found that the half which remained alive gave rise to only one-half of an embryo, thus '^ The Organism as a Whole, 137. 36 /few/., 141. ORIGIN OF SPECIES 221 confirming an older observation of Roux. When, however, Morgan put the egg upside down after the destruction of one of the first two cells, and com- pressed the eggs between two glass plates, the sur- viving half of the egg gave rise to a perfect embryo of half-size (and not to a half-embryo of normal size as before)."^^ The interest that attaches to these monstrosities produced by experimental embryology, has been largely due to the fact that normally one egg gives rise to only one individual. However, these experi- ments are of extreme interest to my theory. Concerning man: Necessarily, most of the facts known about the details of the process of fertilization have been gained through observation of, and ex- perimentation with, lowly organisms. However, the human ovum and spermatozoon are structurally built on the same lines as the ova and spermatozoa of the animals which have been the subject of elaborate experiments. The human ovum (about 1/120 inch in diameter) is imbedded in the Graafian follicle, a vesicle about as large as a pinhead. Periodically an ovum ripens in one or the other of the two ovaries, and is then discharged from the ovary and carried to the uterus. Here, in the event of impregnation, ^ The Mechanistic Conception of Life, 216. 222 WHAT IS LIFE the ovum gives rise to a new individual; otherwise it soon dies. To repeat : FertiHzation, conception, having taken place, immediately the process of cell division com- mences. With the first division of the impregnated ovum, the growth and development of the new in- dividual is begun. Conception, fertilization, once having taken place (in normal fertilization that means when the spermatozoon has entered the egg), the egg passes into an irreversible condition. It may die, but if it does, it is the incipient new individual that dies. An unfertilized egg is a potential new individual; a fertilized egg is actually a new in- dividual in its initial stage of existence. The be- ginning of the new individual dates from the moment of conception. {See p. 164.) The mother supplies everything for the embryo but a single cell, the microscopic germ-cell supplied by the father in the fertilization of the ovum. Up to birth, the embryo is vegetal in its mode of obtaining nourishment: at an early stage what may be de- scribed as a stem-root of the embryo buries itself in the food supply of the egg or the placenta of the maternal organ. This in fewest words outlines the process of sexual reproduction. It is necessary now to note more closely the re- ORIGIN OF SPECIES 223 lation of the spermatozoon to the ovum in fertiHza- tion. Some cytologists (thus O. Hertwig) defined fer- tilization as the fusion of the two nuclei, the nucleus of the sperm and the nucleus of the egg. But this definition had to be abandoned in the light of later experimental knowledge. All the successful experi- ments on artificial parthenogenesis disprove the idea that the fusion of the two nuclei is necessary to fertilize, or activate, the egg. In some experiments by Boveri, "an enucleated fragment of an e^gg was fertilized with a spermatozoon of a foreign species." It was Boveri's conclusion, shared by many later authorities, that the centrosome of the spermatozoon is the essential organ that brings about division in the egg. However, it was found that this theory claims too much for the centrosome as an organ. A flood of light has been shed upon the nature of the process of fertilization by Jacques Loeb's remark- able experiments on the artificial fertilization of echinoderms — sea-urchin and starfish. Jacques Loeb has been quoted repeatedly; and here it may be noted that Dr. Loeb's brilliant and epoch-making work represents the highest point of experimental knowledge of life thus far attained by science. Needless to say, much work in this field of artificial parthenogenesis and of experimental em- 224 WE AT IS LIFE bryology has also been done, with remarkable results, by not a few other distinguished investigators. Jacques Loeb's work included a variety of elabor- ate experiments. But his crowning achievement was the demonstration "that eggs which naturally de- velop only when a spermatozoon enters, can be caused to develop artificially by certain physical and chemical means. "^^ Loeb is again quoted: "Experiments show that it is possible to com- pletely imitate by physicochemical means the effect of the spermatozoon upon the sea-urchin egg"39 Again : "It may be mentioned that in the eggs of many animals the effect of the entrance of the sperma- tozoon manifests itself almost instantly by a characteristic change, namely, the formation of the so-called membrane of fertilization In 1905 I succeeded in finding a method by which it is possible to call forth the formation of a membrane of fertilization without apparent injury to the egg It was noticed that all the agencies which cause cytolysis also cause membrane formation."^" '* Jacques Loeb, Dynamics of Living Matter, 165. " IbicL. 171. " The Mechanistic Conception of Life, 129, 130, 132. ORIGIN OF 8PECIE8 225 Again: "I am inclined to believe that the direct and essential effect of the spermatozoon and the methods of artificial parthenogenesis is the starting of a definite chemical process, and that the formation of astrospheres is only a secondary effect of this. It is in harmony with this idea that the process of segmentation in the case of artificial parthenogenesis is entirely regular, and does not differ from that of fertilized eggs, pro- vided that the right concentration and time of exposure are selected. "^^ It must be noted that in order that an egg may be fertilized, or activated, either by a spermatozoon or artificially, it must be in the specific condition de- scribed as "ripe." Loeb describes,^^ in the case of the egg of the starfish, that the nucleus must have become dissolved in the protoplasm. It has been established, then, in numerous in- stances that in fertilization the life-activity of the spermatozoon can be duplicated by artificial means. As Loeb shows: "The objection raised that the phenomena are limited to a few species soon became untenable since it has been possible to produce arti- ficial parthenogenesis in the eggs of plants {Fucus *i Dynamics of Living Matter, 172, 176, 178. « Ibid., 172. 226 WHAT 18 LIFE according to Overton) as well as of animals, from echinoderms up to the frog."^^ Again: "The fact that the method which causes artificial partheno- genesis in the eggs of many animals acts in the same way in the case of the eggs of plants indicates the identity of this process in all living organisms."^* Concerning the egg, all the many successful experi- ments that have been made on artificial partheno- genesis, have demonstrated that fertilization of the egg can be effected by any means that can cause adequate "chemical" changes in the "ripe" egg. Anything that initiates certain specific changes in the egg, induces formation of the fertilization mem- brane and the development of the egg into an embryo. Experimenting on nereis, F. R. Lillie found that fertilization of the egg can be effected by a spermato- zoon from which the tail, the middle-piece and part of the head has been removed. As stated before, the mere piercing of the frog's egg resulted in the development of the egg and the production of an embryo that grew to maturity. Various physicochemical means have been success- fully employed to cause the fertilization (activation) of the eggs of a variety of forms. Further, perhaps most interesting of all, the fertilization (activation) *' The Organism as a Whole, 123. ** Artificial Parthenogenesis and Fertilization, 279. ORIGIN OF SPECIES 227 of eggs has been effected by exposing them to certain rays. Jacques Loeb writes on the "activation of the un- fertilized egg by ultra-violet rays": "The writer's previous experiments have shown that any substance which acts as a cytolytic agency can also produce artificial parthenogenesis. It was found, indeed, that the unfertilized eggs of the sea-urchin Arbaciay as well as those of the annelid, Chaetopterus, can be caused to develop by a short treatment with the Heraeus quartz arc lamp."^^ One of the outstanding things brought to light by the experiments on artificial parthenogenesis, is that apparently "the egg is the future embryo." Loeb says: "The idea that the egg is the future embryo is supported by the fact that we can call forth a normal organism from an unfertilized egg by artificial means; while it is apparently impossible to cause the spermatozoon to develop into an organism outside the egg."^^ Loeb at one time had "seven parthenogenetic frogs over a year old, produced by merely puncturing the eggs with a fine needle." At a later writing he re- ported that "two more of the parthenogenetic frogs over a year old died. Both were males. "^^ *5 Science, November 6, 1914. ** The Organism as a Whole, 8, 9. *7 Ibid., 125. 228 WE AT IS LIFE Concerning the idea that the egg is the future embryo, Loeb says further: "The fact that the egg of so high a form as the frog can be made to develop into a perfect and normal animal without a spermato- zoon— although normally the egg of this form does not develop unless a spermatozoon enters — corrobor- ates the idea .... that the egg is the future embryo and animal; and that the spermatozoon, aside from its activating effect, only transmits Mendelian char- acters to the egg."''^ The conclusion of biology, then, is that the egg is the future embryo. The egg is absolutely specific- The egg is the future embryo of an individual of the particular species to which its mother organism belongs. The species is represented by the egg, and reproduced by it. The question of heredity is closely bound up with the fact that the egg is the future embryo. (As Bateson points out, recognition of the sig- nificance of heredity is modern. That the idea of heredity in terms of blood — an idea sometimes sug- gested in common speech — has no foundation in fact, is obvious, since every organic individual starts his existence as a microscopic cell.) A fertilized ovum that develops and grows to maturity of the embryo and of the adult form, always ** The Organism as a Wliole, 126. ORIGIN OF SPECIES 229 reproduces the leading characteristics of the species to which its parents belong. Heredity has to do with the preservation of traits, or characteristics, peculiar in general to the species and in particular to the progenitors of an offspring. The possession of special traits by an individual when assignable to heredity, may come as an inheritance from, or through, the mother or from, or through, the father. It is well known that heredity does not generally manifest itself in a simple reappearance in the off- spring of maternal traits plus paternal traits. Slight variations are the order; and these are not haphazard products. The classic work of Mendel and De Vries has demonstrated this experimentally. All the results obtained by these investigators were secured by means of artificial selection. Especially to the point is the unquestioned fact that so far as the offspring is concerned, sexual selection operates irrevocably at the moment of fertilization. Hereditary traits can be transmitted only at the time of fertilization. Thus fertilization (when a spermatozoon is involved) is unthinkable apart from heredity, and heredity is unthinkable apart from fertilization. In fertilization, the spermatozoon then plainly has the dual role of initiating specific changes in the egg (which lead to cell division and growth), and of 230 WHAT IS LIFE conveying hereditary traits. It is Jacques Loeb's finding: "The analysis of the process of fertilization by the spermatozoon shows that we must dis- criminate between two kinds of effects, the hereditary effect and the activating or developmental effect."^^ Biologists today are generally agreed that the factors, or carriers, of heredity are the chromosomes, bodies, or structures, that are found in the nucleus of the egg and in the head of the spermatozoon; and which may be identified under suitable conditions.^" "Chromosomes" are thought to be the carriers of individual hereditary traits; individual hereditary traits being distinguished from the general traits of species heredity. As the name itself indicates, chromosomes furnish a purely morphological conception of heredity; and, of course, no biologist supposes that visible structures can supply an ultimate conception of heredity. {See pp. 258 and 259.) Henry Fairfield Osborn (the famous paleontologist who has been freely quoted) some years ago urged an "energy" conception of heredity — "and away from the matter and form conceptions." Osborn said that "we may imagine that the energy which lies in the *^ The Mechanistic Conception of Life, 158. ^^ See August Koehler, Zeitschrift fiir wissenschaftliche Mikrosko-pie, XXI, 129; W. T. Bovie, Journal of Medical Research, XXXIX, 247. ORIGIN OF SPECIES 231 life-germ of heredity is very great per unit of mass of the matter which contains it."" In heredity numerous specific and pronounced paternal traits are transmitted to the offspring through the medium of a single cell, so small that one drop may contain millions of them. That the human child inherits psychic qualities and traits from the two parents, is a widely held view. Thus, Eugen Fischer, director of the Kaiser Wilhelm Institute for Anthro- pology, recently stated that "the question as to the hereditary transmission of mental endowments must be answered absolutely in the affirmative." It is plain that morphology, physiology, and chemistry cannot throw much light upon the problem of how ultimately this is possible. My theory of heredity is an integral part of my theory of life; it results directly from the basic con- ception of life and the life-process which the theory gives. The germ-cells themselves, the activation of the egg in fertilization, and the entire series of changes initiated by the entrance of the spermatozoon into the egg or (in artificial parthenogenesis) by certain physicochemical means — all must be conceived in the terms of the theory. According to the theory, the sex-cells (like all other " The Origin and Evolution of Life, 12. 232 WHAT IS LIFE living matter) consist of two systems, a Y-system and a Z-system, as described. And it is the constitu- tion, the organization, the pattern, of the Z-system of the germ-cell — not the chemical constitution of the matter (the Y-system) of the germ-cell, nor anything else connected with the germ-cell — which primarily determines that given the egg of a Pla- norbis, only a Planorbis can result. The egg of any organism never by any possible chance develops into anything but an individual of the same kind as its parent. This phenomenon of specificity cannot be accounted for except on the view which here is briefly stated; on the other hand, specificity, such as is actually observed, inevitably must characterize the process and product due to a germ-cell that is constituted as the theory describes it. Suitable conditions predicated, it is the pattern of the grouping of the elementary units that constitute the Z-system of a germ-cell that determines what series of reactions can take place; one series leading to another, and that to the next; and so on, until the limit of reactions proper to the organism (always a dual system), as determined by the germ-cell, has been reached. Obviously, the determinants of the series for any one of the higher organisms lie packed in the microscopic germ-cell. This fact finds its ORIGIN OF SPECIES 233 simple interpretation in the terms of the theory. The fanciful idea that the germ-cell contains the miniature organism or a rudimentary organism, of course has no place in my theory. The theory requires only that the Z-system of the germ-cells be organized into a specific pattern, that pattern which (following activa- tion of the egg) through the series of successive re- actions that are determined by it, results in a new organism that is like the parent-form. The theory thus offers the concept that (suitable, normal conditions predicated) heredity, including (1) the reduplication of kind, (2) the recurrence of traits, (3) the limits of possible variation, (4) the limit of possible development, (5) the limit of possible growth, and (6) the length of the average life-span of the organism, and also including (7) the specificity of species, is determined by the constitution (pattern) of the Z-system of the detached particle of the parent organism, or sex-cells, by which particle heredity is conveyed. The new theory of life treats of the origin of species, of specificity and variety, and the successive appear- ance of higher and higher forms of life on the earth, as follows: The formation of the dual-system, the origin of life, occurs granted only a limited set of conditions. No particular complexity is required : The life-forms that arise are correspondingly simple. 234 WHAT IS LIFE The series of reactions that is possible to life-forms is determined (1) by the specific condition that determines the origin, or formation, of the dual- system (without which condition it cannot form) ; and (2) by the degree of complexity of the factors that combine to make the conditions. The "conditions," the "factors" and the "complexity" here referred to, of course all are physicochemical. It is obvious that the degree of complexity that obtains at the formation of a dual-system is a most important factor in determining the series of re- actions that may be completed by the system, and thus in determining the life-form itself. But only a limited series of reactions is possible to the organism, considered as a dual-system that con- sists of a Z-system and a material system, as the theory defines it. It is absolutely impossible that these should be exceeded. The possibilities of varia- tion are simply and solely those which are permitted by these exact limitations. Always the ultimate determinant is the constitution and complexity of the Z-system. The specificity of the relations that govern the life- process {basically considered) is such that it seems extremely improbable that the earliest life-forms on the earth could have developed into the later higher life- forms. ORIGIN OF SPECIES 236 Geological records clearly show that the earth passed through at least several great periods of well- nigh general upheaval and changes of continental surfaces. The end of every one of these great epochal periods provided a maximum of the conditions which according to the theory are necessary for the initia- tion of life. A critical concentration of ions always develops whenever the conditions permit; and the formation of dual-systems, according to the theory, always occurs whenever the conditions permit. As it has been shown, geology indeed testifies that following the several great periods of upheaval which were attended by destruction (seemingly verging on extinction) of life on land, new and higher life-forms made their relatively abrupt appearance. The cause of the successive appearance of higher and higher life-forms on the earth during geologic time is found, I hold, in the fact that each succeeding time in the earth's history which was favorable to the wholesale origin of life provided greater complexity of conditions {physicochemical cojiditions) than the preceding times. In extensiveness some of the great occasions that were favorable for the repeated wholesale origin of life, approach that of the early earth. But without a doubt, each succeeding occasion had greater com- plexity. Geologists and paleontologists (Walcott, 236 W H AT IS LIFE Schuchert, Osborn) allow about eighteen million years to archeozoic time. During these millions of years organic matter began to accumulate, even then greatly increasing the complexity of physicochemical conditions. Whether or not the early earth had direct light from the sun, and whether or not the ocean was salt from its beginning, both sunlight and salt have played an almost inestimably great role in the later history of life on the earth. Whatever the constitution of the early atmosphere may have been, it has changed greatly during geologic time. To realize the importance of this one factor, one needs only to call to mind the fact that any considerable modification of the present at- mosphere would result in the death of the human race. As students hold, it does not seem likely that the average temperature has varied very greatly since life first appeared on the earth, that is, when and where life flourished; for the peculiar life-process can take place only within a very narrow range of temperatures. The presence of glaciers and glacial action, prolonged and over wide areas, necessarily has meant absence of life. The present adjustment between temperature and atmosphere and the highest life-forms on the earth, is ORIGIN OF SPECIES 237 of very recent establishment — very recent, that is, compared with the total of the many millions of years that geologic history covers. The increase in complexity (physicochemical com- plexity) of conditions on the earth, broadly viewed, has been a gradual process; though great upheavals and cataclysmic changes indeed have occurred at intervals, some have fancied, with almost rhythmic regularity. The increased physicochemical complexity that obtained at each succeeding time in the earth's history that provided the conditions which (according to the theory) must have meant the repeated, very general origin of life-forms, higher life-forms, register- ing the increased complexity, then, was due to several causes. These are: 1. The accumulation of organic substances. The great modifications caused by the presence of organic substances are described by geologists and geo- chemists. 2. Changes in the atmosphere, the great "turbu- lent sea" of gases that lies above the earth. ^^ That the atmosphere has undergone great changes is pointed out by Arrhenius^^ and is fully recognized by all writers on the subject of life on the earth. ^* See William Ramsay, The Gases of the Atmosphere. " Das Schicksal der Planeten, 51. 238 WH AT IS LIFE 3. The change from (probable) faint light or, perhaps, mere heat from the sun to direct sunlight. How completely the presence of life on the earth is dependent upon the sun, is known to everyone. Since, as now known, the sun pours torrents of elec- trons upon the earth, and sunlight exerts actual pressure,^'' the enormity of this change is evident. All these causes, of course, are interrelated and were interactive. 4. The great periods of convulsions and upheaval with their changes of the earth's surface. The untold significance of these times as mighty factors in determining the possibility of the appearance of higher life-forms, remains to be realized. Heretofore it has been thought and taught (by those who believe that all existing life-forms are descended from the first and lowliest forms of life on the early earth — by practically "everybody") that life advanced in spite of these disturbances. Of course, all pelagic and bathybic forms were unaffected by changes of continental surfaces, and flourished as temperature conditions permitted. Undoubtedly "many new forms have appeared (or 'evolution has gone on') in the sea." Possibly numerous surviving forms, through adaptation to changed environments, suffered modifications because of these disturbances. " J. H. Poynting, The Pressure of Light. ORIGIN OF SPECIES 239 But according to my theory, the immediate and direct means whereby the appearance of higher life- forms was made possible were the times which over wide areas meant changes of the earth's surface and the interruption of the life-process on land, times that were followed by conditions which were suitable to the new origin of life. It is a matter of common observation that life flourishes in every nook and cranny that will support it. When then at any one of several periods in geologic history, the earth was crowded with the highest forms of life which up to that time had appeared (and with lower forms), not much further advance was possible until there was opportunity for a new beginning. The conditions that necessarily followed the great upheavals and changes of the earth's surface provided this opportunity. Each great advance to higher life-forms was made possible by a new beginning. Necessarily each succeeding recurrence of wide- spread conditions suitable for the origin of life did not, could not, provide these conditions uniformly throughout, but only uniformly in a general way; and since every slightest difference in constituents or conditions necessarily is reflected, or registered, in corresponding variation, there must have arisen great varieties of forms which, on culmination, exhibited 240 WE AT IS LIFE much general similarity and much diversity in detail. Always, of course, earlier, lower life-forms persisted as conditions permitted, "adapting" themselves to the limit of possibility. The possibilities of adapta- tion, however, necessarily were limited. "Adapta- tion" as a factor in evolution has been greatly exaggerated. That the life-forms which escaped destruction when the wholesale loss of life, with extinction of many species, occurred, had any part in the evolution of higher forms that followed these destructive periods, seems most unlikely. Most, if not all such surviving forms in all probability had become distinct forms long before the disturbances set in. And, according to my theory, a ''species'' (such as the life-forms, mentioned by Osborn, that remained static for millions of years — see pp. 207,208) must be conceived to be the end of a series; not a step, or link, to higher forms. A dual-system such as the theory conceives every life-form to be, is a strictly limited system, a system limited by its own constitution. Any occasion, every occasion, that gave rise to life, gave rise to life-forms that were strictly limited as to possibilities of de- velopment, and of variability. Inevitably, when the limit of these possibilities was reached, sooner or later in geologic time, the "pattern" became rigid, no further development, or evolution, being possible. ORIGIN OF SPECIES 241 Reproduction then became a reduplication that faithfully copied the parent form, the succeeding generations showing only such variations as attend the transmission of hereditary traits from two parents. Cross breeding, when possible, generally resulted in sterile offspring. The form was fixed. (See p. 138.) As a fixed form of this kind I describe a species. And thus the theory accounts for the fixity, the specificity, of the species of geologic times which, Osborn and Loeb have said, persisted for "from two to possibly two hundred millions of years." {See p. 207.) One can conceive the possibility or probability of one incipient form, if sufficiently complex, giving rise to a variety of forms that ultimately resulted in separate species. Also some forms would remain less rigid than others, and these might produce a series in which the successive generations developed specific characteristics; or these less rigid forms through interbreeding would result in slight or pronounced variations. There is the famous example of the evolution of the horse, described by Henry Fairfield Osborn, ^^ the other of the Formenreihe of Waagen; " The Origin and Evolution of Life, 266-269; "Recent Advances in our Knowledge of the Horse," Proceedings of the American Philosophical Society, XLIII (April, 1904), 156; "The Evolution of the Horse," Report British Associ- ation for the Advancement of Science, 1905, pages 607 and 608; "The Continuous Origin of Certain Unit Characters as Observed by a Paleontologist," Harvey Society Volume, seventh series, November, 1912, pages 153-204. 242 WHAT 18 LIFE and hybrids and "intergrades" are numerous. How- ever, it is necessary to exercise extreme caution in assigning similar species to a common ancestral form. My theory brings about a curious reversal: The current theory of descent grants almost unlimited possibilities of evolution, demanding only the pri- mary, single origin of life. To account for the origin of life was thought to be impossible. According to my theory of life, the origin of life is a phenomenon that is bound to take place granted only a very limited set of physicochemical conditions. But the possibilities of evolution of any forms that arise — these, it appears, are strictly limited. It would seem that most existing species could not be other than specific and fixed in their essential characteristics, the limit of their development (evo- lution) having been reached long ago. Specificity fixity of species, then, may not be conceived in the sense of something fatal that was impressed upon a life-form; but must be understood to mean merely that the limit of the reactions that by reason of its constitution were made possible to any newly-arisen life-form (the reactions that represent an organism of a certain definite species), was reached long ago. The average limit of possible reactions of any form having been reached, the form necessarily became rigid. ORIGIN OF SPECIES 243 The pattern having become rigid, succeeding genera- tions demonstrate the "fixity of species." At several great periods in the earth's history, according to my theory, countless separate life-forms could originate, doubtless did originate at the same time. In each case, the process of development (evolution) inevitably continued until the form be- came rigid. Eventually, then, each of these different forms necessarily resulted in one or more separate species. That these conclusions have direct bearing on the problem of man's descent is obvious. The doctrine of man's descent is no stronger than the weakest link in the general descent theory. But that absolute specificity rules in all life-processes as in all other processes, cannot longer be doubted by anyone who is familiar with atomic physics. Therefore, emphatically, the painful crudity, the vague generalizations, and the inexactness of the old forms of expression relative to the facts of the di- versity of life-forms and their causes, which have been current in most of the evolutionary literature of the fifty and more years after Darwin, must be rejected utterly. High-sounding generalizations, however plausible, are absolutely meaningless to a physicist or a physical chemist. He knows only exact quantities and quantitative relations and their re- 244 WHAT 18 LIFE suits. The current general theory of descent is not compatible with the very specific, rigid, and exacting laws of atomic physics. And thus it comes about that the finding of the other, earlier, more general sciences concerning man's descent is reversed : The new verdict is that it would seem almost certain that the strain which resulted in "man" was a separate one from the beginning. It is extremely improbable that there should have developed a common ancestor from which (as many think, at a late date) both man and the apes evolved; and the idea that apes degenerated from an ancestral stock from which man evolved, is pure fancy. The reasons for rejecting the current doctrine of man's descent are: 1. The same reasons which apply to the general theory of descent; and 2. Specific reasons which arise from a comparison of man and ape. My theory of the origin of species, and of the cause of the successive appearance of higher and higher forms of life on the earth during geologic time, then, is dia- metrically opposed to the current theory of descent, which teaches that all higher organisms now existing have descended through an unbroken line, and have advanced by insensible gradations or sudden mutations from the ORIGIN OF SPECIES 245 earliest, the lowest, forms of life that appeared on the planet. It would appear that geology fully grants the facts that are necessary to the new theory. The concept that has been given of the origin of species, of the fixity of species and limit of variability, is that of my theory interpreting the natural process unmodified by artificial methods. It is a peculiar fact, however, and one that must be carefully noted, that the life-process as conceived by the theory is such that it must be assumed not only that definite, fixed, species necessarily arose in geologic time, but also that artificial methods and cross-breeding easily should succeed with various life-forms in achieving the ex- perimental transmutation of species. For, remember- ing the definition of "species," it is plain that the problem of transmuting a species into something else consists merely in disturbing or breaking up a specific state of equilibrium. In experimentation, various sets of conditions (physicochemical and other con- ditions) are carefully arranged and regulated in the deliberate effort to bring about a desired result. In this way conditions can be secured which, according to the theory of chance, might never have occurred in the natural state. Thus, for example, various luscious hybrid fruits now commonly enjoyed, prob- ably never would have been produced unaided by 246 WHAT IS LIFE artificial methods. Most notable are the experiments (of H. J. Muller, of the University of Texas, T. H. Goodspeed and A. R. Olson, of the University of California, W. C. Curtis, of the University of Mis- souri, and others) in which by exposing living or- ganisms to powerful beams of X-rays that were just below fatal intensity, a large number of mutations, or "sports," were produced in the third generation. Various life-forms — fruit-flies, mice, hen's eggs, jelly- fish, tobacco plants, etc. — have been subjected to this treatment with X-rays, and similar effects were found. Numerous other experiments that have been made also support my view. Chapter Eight Why Was This Theory of Life Not Stated Before? THE theory offers a solution that seems so simple and obvious that the only wonder of it is that it was not stated before. However, many of the facts on which it is based, and without which it could not be formulated, have been brought to light only recently. Biology itself is a very young science, and atomic physics is still younger. Modern biology may be said to date from the dis- covery of the cell. (Von Mohl, Schleiden and Schwann.) It was in 1839 that Schwann discovered that the human ovum is a cell, and recognized that animals and plants are built up of cells. And as a writer pointed out on the occasion of the centenary of Schwann's birth (Dec. 7, 1910), "the first years of Schwann's scientific activities fell within those happy days when it was still possible, in the words of Henle, *by scraping with the blade of a scalpel or with the fingernail over an animal membrane, to make fundamental discoveries.' " Following the revolution of all former conceptions 247 248 WHAT IS LIFE of life caused by the discovery of the cell, for about fifty years emphasis in biology was almost entirely placed on morphology. Concerning the cell, early views deemed the cell wall as hardly less important than the ''contents" of the cell. It was by no means known that the apparently simple cell constituents really are "incredibly complex," and that the cell is a unit which, as since shown by cytologists, exists in most various degrees of complexity. The conception of the cell as very close to the origin of life, and the idea of the importance of the cell wall, has been lingering. Thus it only a decade ago (1916) found expression by an authority in geology (Thomas Chrowder Chamberlin^) when among the conditions that might be considered favorable for the origin of life on the early earth, was mentioned the probable presence of cell-like, comb- like formations. Blitschli thought he discovered a comb-like structure in gels, but the "discovery" was discredited by Wolfgang Pauli. Naturally then, to be able to produce an artificial "cell," hollow cham- ber, membrane, was thought to be a very high goal. However, it has been found that artificial cells (Wilhelm Pfeffer's and Moritz Traube's) after all do not contribute much toward the solution of life. It is well known what importance the evolutionists ' The Origin of the Earth, 250-261. WHY WAS THIS THEORY NOT STATED BEFORE 249 of the second half of the nineteenth century attached to form and structure, to the neglect of causes save for vague ones such as "function," "use," and "dis- use." There was incessant and almost exclusive appeal to comparative anatomy, embryology, and paleontology — all morphological. Henry Fairfield Osborn finds: "The old paths of research have led nowhere, and the question arises: What lines shall new researches and experiments follow?"^ Osborn urged an "energy conception" of the origin and evolution of life. If one were asked today to state the trend in biology, one could answer in a word: away from mor- phology. Of course, the word "morphology" is used in its obvious sense, as it has been used since Goethe first coined the term ^'die MorpJiologie" \ for, cer- tainly, it is true, and guaranteed by atomic physics, that (as P. P. von Weimarn insists) amorphic chaos can be found nowhere in "nature." Modern colloid chemistry has been making its rapid strides only within the lifetime of the present workers. Only within the last few years have de- mands been made that it, one of the branches of physical chemistry, be ranked as a separate science. A German reviewer referred to Bechhold's Die Kol- loide in Biologie und Medizin (English translation ' The Origin and Evolution of Life, 10. 260 WHAT 18 LIFE and second German edition 1919) as pioneer effort. Wolfgang Ostwald, in the volume which embodies his lectures delivered in 1913 and 1914 before some of the leading universities in the United States, calls colloids "the world of neglected dimensions," and insists that "just as normal causal biology must be edited — must be rewritten in fact — in the terms of colloid chem- istry, even so must pathology be rewritten."^ Ost- wald indeed called colloid chemistry "the promised land of the biological scientist." It is well known that the employment of physico- chemical methods, especially in the hands of Jacques Loeb, was crowned with brilliant results. The successful substitution of physicochemical means for the life-activity of the spermatozoon of certain organisms, the work of Jacques Loeb on artificial parthenogenesis (mentioned repeatedly), has been the decisive factor in working a revolution of con- ceptions about life which stands out as the most conspicuous thing in biology since the discovery of the cell. Concerning these experiments, Loeb himself said: "I consider the chief value of the experiments on artificial parthenogenesis to be the fact that they transfer the problem of fertilization from the realm of morphology into the realm of physical chem- istry."* ' Theoretical and Applied Colloid Chemistry, 171. * The Mechanistic Conception of Life, 123. WHY WAS THIS THEORY NOT STATED BEFORE 251 Besides Loeb's work and the work of others on artificial parthenogenesis, much other work also has been done which indicates that morphology is of only secondary importance. Thus, for example, as Wolf- gang Pauli insists, the concept of a boundary phase has to do service in the absence of histologic evidence of a membrane between different tissue constituents. Then there are the experiments on the growth and form modifying tropisms of plants (J. Sachs), and of organs of certain animals (Loeb^). One also may recall Brown-Sequard's classic experiments and theories on sex-gland transplantation (1888), and the earlier (1849) experiments of Berthold, who found that a hen into which the testicles of a young cock had been transplanted, developed secondary sex characteristics — masculine voice, love of combat, etc. But the trend away from morphology in biology, and the substitution of the methods of physical chemistry for those of morphology, is not the end. Life, the organism, cannot be interpreted adequately in terms of physical chemistry any more than in terms of morphology. This does not mean that, depending on the method of approach, the organism may not be described as a series of chemical reactions, the rate of progression of which, in some organisms ' Forced Movements, Tropisms, and Animal Conduct. 262 WHAT IS LIFE at least, can be definitely accelerated or retarded by changes in the temperature in which the organ- ism is kept;^ or as an aggregate of cells; as like a galvanic cell — transforming chemical energy into electrical energy; or (the higher organism) as a mechanical engine, as Arthur Keith describes it in his volume The Engine of the Human Body, and De la Mettrie (b. 1709) pictures it in his Man a Machine. Each description is true but inadequate, as were the five different descriptions which the five blind sages of India gave of an elephant. It would seem that physical chemistry in the service of biology already is about exhausted — of course not as to countless possible experiments that never yet have been made, but rather so far as con- cerns any further great fundamental contributions towards the elucidation of the problem of life. The one capital contribution which physical chemistry has yet to furnish, experimental abiogenesis, has been an impractical line of research in the absence of a working theory of the origin of life. {See p. 180.) Therefore, although experimental abiogenesis is seen as the challenging goal of biology, not a few of the leading representatives of science retain the idea of panspermia. And this in face of the fact that no evidence for panspermatism ever has been discovered. • See Jacques Loeb, Scientific Monthly, December, 1919. WHY WAS THIS THEORY NOT STATED BEFORE 263 The hypothesis has been put forth gratuitously, as the ancient Greeks put it forth, in the absence of a definition of what constitutes life and determines the origin of life. That life cannot be interpreted adequately in the terms of physical chemistry is plain from the definite limitations of physical chemistry. In the division of labor, which alone now divides one science from another, it is allotted to physical chemistry to work with the chemical atom, the molecule, and the ion. When then, for instance, membrane permeability is interpreted in terms of ions of positive or negative sign, in pointing out the ion (the element) and its sign as the active agent, physical chemistry reaches its limit. Unaided, it can go no further. But today no one thinks of the chemical atom and the ion as ultimate units. It bears repeating: Concerning the chemical elements, it is an indisputable fact now firmly established, that they are not simple but com- pound, and not only compound, but trebly complex; and further, that all their qualitative properties are determined numerically. Elucidation of the con- stitution of matter, basically considered, is furnished by theoretical (mathematical) and experimental physics. How then, reasonably, can one expect physical chemistry to perform for biology what admittedly it cannot do and is not expected to do in 254 WHAT 18 LIFE the realm of the inorganic — yield fundamental con- cepts ? Soddy teaches: "The chemical analysis of matter is, even within its own province, superficial rather than ultimate."^ In order to get at the inner constitution of matter, "ordinary" inorganic matter, physics has devised, has had to devise, methods a million million times more sensitive than ordinary chemical analysis. How can one expect the secret of living matter to reveal itself to methods too clumsy for the inorganic? One cannot expect to get results by using a tool comparable to a mile measure when what is needed is one correspond- ing to an inch. Therefore in biological inquiry, even when physical chemistry points out and describes causes and effects, such as identifying certain changes as of rate of action, with change of electrical sign of a specific ion, the demand for a further reduction of the terms cannot be suppressed. The terms to which the atom and ion and their activities must be reduced of course are the terms of atomic physics. This is obvious, since the chemical elements which are present in organisms and involved in life-processes, are like the same chemical elements found in the inorganic, fundamental conceptions of which are supplied by atomic physics. Jacques Loeb, whose ^ Nature, July 19, 1917. WHY WAS THIS THEORY NOT STATED BEFORE 255 investigations into the effects of ions led him to the successful employment of physicochemical methods in research on artificial parthenogenesis, later con- ducted experiments on diffusion, in which he inter- preted the action of the ion in terms of atomic physics. Wolfgang Pauli believes: "There can be little doubt that out of the study of the physicochemical properties of the colloids there will spring a new bud of physical physiology in which the application of the modern teachings of electricity will play a primary role. The physiology which recognizes in the neighboring sciences of physics and chem- istry that profound revolutionizing influence of the newer electrical investigations, which do not stop before even the most sacred and funda- mental conceptions of this subject, must con- sider it as a next most worthy task to guarantee itself its share in the new conquests of scientific knowledge."^ The terms of physical chemistry then admittedly are utterly inadequate to express the ultimate rela- tions which obtain among the phenomena of life, or the organism. It comes to this: Life, any and all life-phenomena and the organism as a whole, cannot • Physical Chemistry in the Service of Medicine, 155. 266 WHAT IS LIFE be interpreted adequately in the terms of physical chemistry for the simple reason that the inorganic cannot be interpreted adequately in these terms. There seems to be no reason for accepting as the final word in biological research an analysis which is not accepted as the final word concerning the in- organic, unless the mere circumstance that an experi- ment is related to problems of life-processes consti- tutes reason why the matter and electricity involved should not be reduced to the terms of atomic physics. Of course, this latter idea is absurd. To insist that the interpretation of the organism in terms of the electron and of atomic physics is legitimate, is merely to insist in a specific way on the relationship which exists between the organic and the inorganic on which many — Helmholtz at the age of twenty-five, Ernst Mach to the rounding-out of his scientific career, Jacques Loeb, Wilhelm Ostwald, Sir Jagadis C. Bose, and many others — forced by overwhelming evidence, have insisted. Indeed, a large number of students see an "all-embracing unity," and therefore, with Wilhelm Ostwald, insist on "a doctrine which ex- cludes all double-entry bookkeeping, which removes all barriers, hitherto regarded as insurmountable, between inner and outer life, between the life of the present and that of the future, between the existence of the body and that of the soul, and which compre- WHY WAS THIS THEORY NOT STATED BEFORE 257 hends all these things in a single unity, that extends everywhere and leaves nothing outside its scope. "^ A strong plea for the stating of the facts of psy- chology in the general terms of science is made by the psychologist, J, B. Watson, formerly of Johns Hopkins University: "The key which will unlock the door of any other scientific structure will unlock the door of psychology. The differences among the various sciences now are only those necessitated by the division of labor. Until psychology recognizes this and discards everything which cannot be stated in the universal terms of science, she does not deserve her place in the sun."^° Thus Jacques Loeb : "The physical researches of the last ten years have put the atomistic theory of matter and electricity on a definite and in all probability permanent basis. We know the exact number of molecules in a given mass of any substance whose molecular weight is known to us, and we know the exact charge of a single electron. This per- mits us to state as the ultimate aim of the physical sciences the visualization of all phe- nomena in terms of groupings and displacements of ultimate particles, and since there is no dis- ' Monism as the Goal of Civilization, 5, 6. ^^ Psychology from the Standpoint of Behavior. 258 WHAT IS LIFE continuity between the matter constituting the living and non-living world the goal of biology can be expressed in the same way."" Wolfgang Ostwald declares: "Like the chemistry, so must the physics of organized substance be analyzed into unit processes and through gradual rebuilding from these be resurrected into a synthetic biology. "^^ Of the admitted legitimacy then of interpreting life in terms of atomic physics there can be no doubt. How far from the goal biology has been, appears from the fact that heredity is interpreted in terms of chromosomes. {See p. 230.) To be sure, especially when one reflects that the scientific conception of heredity only dates from Herbert Spencer, heredity in terms of chromosomes is seen as a marvelous advance over heredity in terms of ^'adaptation." As Bateson points out: "The absence of any definite progress in genetics in the last century was in great measure due to the exclusive prominence given to the problem of adaptation. Almost all debates on heredity centered in that part of the subject."^^ However, concerning the unsatisfactoriness of the morphological interpretation of heredity, Ralph S. Lillie, in a paper on The Place of Life in Nature (read " The Organism as a Whole, 1. '* Theoretical and Applied Colloid Chemistry, 170. " Problems of Genetics, 187. WHY WAS THIS THEORY NOT STATED BEFORE 269 before the Royce Club, Harvard University), ex- pressed himself thus: "Most geneticists regard chromosomes as the bearers of hereditary qualities in organisms. But in the physiological sense no such theories of heredity can be regarded as ultimate; if chromo- somes (e.g.) determine the appearance of certain special characters in organisms (as now appears almost certainly to be the case) what determines the appearance of the special qualities possessed by a given set of chromosomes themselves? Surely not a second set of chromosomes — i.e., similar physiological units of a lower order? Evidently these would require a third set of determinants, and so on ad infinitum, like the fleas in Swift's epigram. But the facts of physical science forbid any such regressus since limits to divisibility are set by the atomic or electronic constitution of matter."^* Atomic physics enables a refinement of definite concepts to a degree until recently deemed im- possible. But the thorough establishment of modern atomic physics is of most recent date. As yet com- paratively few persons are thoroughly conversant with the facts of the new atomic physics and the labors (including the early labors of Kaufmann, Laue, other " Journal of Philosophy, Psychology, and Scientific Methods, XVII, 38. 260 WE AT IS LIFE German students, the Braggs, and Henry Moseley) on which it is built. Nevertheless, how general the acceptance of the fundamentals of atomic physics is, may be stated in the words of R. A. Millikan: "Today there is absolutely no philosophy in the field other than the atomic philosophy, at least among physicists. "^^ The facts of atomic physics are absolutely in- dispensable to the comprehensive interpretation of life, the organism. In the absence of much-needed data, then, it was impossible for the would-be inter- preter of the organism to frame an adequate theory of life. Surely that was his misfortune — blame for the tardiness of the development of physics may not be heaped upon him. Lawrence J. Henderson (in 1913) sketched *'the painful advance of physics and chem- istry into the domain of biology," and pointed out *'how progress is beset with well-nigh insuperable obstacles." He concluded : "Thus it is that biological thought has never attained to that finality which appears, at least by contrast, to characterize the greater body of opinions in physical science. "^^ However, the needed facts are now available. And to neglect to make use of all the facts of atomic physics predestines any "theory" of life to certain failure. '^ The Electron, second edition, 10. '" The Fitness of the Environment, 282. WHY WAS THIS THEORY NOT STATED BEFORE 261 The mere recognition of the electron or of the discrete nature of matter and electricity does not take one far. The mere reduction of the units of physical chem- istry— the atom and the ion — to the electron, does not solve the problem of the organism. Plainly, it does not advance our knowledge of the organism in any way that would make possible a statement of the differ- ence between life and non-life, the organism and inorganic matter, in terms of atomic physics. In fact, the mere reduction of the atom and the ion to the electron does not shed even a ray of light on the specific questions about the organism that physical chemistry cannot answer. The bare idea that an immensely large number of atoms, that themselves are built up of a large number of elementary units, constitute a cell or are contained even in chromo- somes or chromatin, and therefore permit of the forming of rich and varied "mosaics," is like the idea that a very great number of cells that build up an organism — one estimate has it twenty-six million million cells in the human body — account for the organism. Neither idea contains anything that in the least would indicate the relationships among these units that result in the larger living aggregate. In connection with the fact (as I hold it to be) that life, that is, the living organism, cannot be interpreted comprehensively without taking account 262 WHAT 18 LIFE of all the facts of atomic physics, it is of very special interest that a department of biophysics has been estabHshed in a number of large institutions. The work is in the field of X-rays, of radium, and of ultra- violet light brought into relation with living matter. {See p. 196.) Seemingly it is only a short step from the much-pursued study of the effects of X-rays and of radium on animal tissue and particularly on cancer, to the study of atomic physics and biophysics, yet the establishment by a great institution of a department of biophysics marks the official recognition of the most significant advance in methods since physical chemistry was first employed to elucidate life phe- nomena. The hour of physics is striking. However, when a textbook by an eminent physiologist (D. Noel Paton^^) still makes the assertion (emphasizing it with italics) that "the science of life has become the science of the chemistry of protoplasm," it is, after all, small wonder that a theory of life based on atomic physics was not formulated before. " Essentials of Human Physiology, fifth edition, 3. Chapter Nine On Proof CONCERNING the theory of life that has been submitted (Chapter Five) it may be urged: 1 . The theory is in entire accord with the accepted findings of atomic physics. 2. The pecuHarities of organic matter, that is, the pecuHarities of the carbon compounds, or combina- tions {see pp. 91, 92) would support well the author's contention that in the dual atomic-intraatomic sys- tem of living matter, the atomic (material) system is the secondary system; i.e., the arrangement of atoms to form molecules in and during the living state is directly or indirectly determined by the intraatomic system, the primary system of the dual system. 3. The theory adequately accounts for the phe- nomena of life basically considered. It accounts for the peculiarities of the organism that distinguish life from non-life. 4. There are no known facts to invalidate or dis- credit it. 263 264 WHAT IS LIFE 5. All pertinent facts find their ready interpreta- tion, that is, classification; and with its aid stubborn difficulties are readily solved. Thus, for example, the cause of man's long infancy, as compared with the ape's short infancy, finds its easy statement when the problem is viewed in the light of the new theory. {See pp. 185-188.) Anatomi- cally man and the great apes are similar; physiologi- cally and chemically there is an extremely close relationship between them; yet the period of time required to reach physiological maturity, in which the same sets of organs and the same functions are involved, in the case of man is several times that required in the case of the ape. Why.^^ The cause of man's long infancy, it appears, simply cannot find its statement by science on any other theory than this theory of life based on atomic physics. Someone said: "He has not adduced proof until he has adduced a fact which is compatible with no other explanation than his own." Such a fact having been adduced, has not proof been adduced? If the exigencies of a theory require that to be true a certain given set of phenomena must be found present under certain specific conditions; and if this set of phenomena is found unmistakably to exist under the specified conditions; and if, furthermore, the facts, or phenomena, for which one is searching ON PROOF 265 as necessary to the theory — in the present case, lengthened infancy with increase of psychic powers — are facts which themselves have been vainly seeking classification (by science) on any theory whatever, and have remained utterly inexplicable: the com- bination amounts to proof for the theory. 6. It is a complete theory, in that "the truly psychical" is included and fully accounted for — accounted for, that is, to the same extent to which anything else may be said to be accounted for. (See p. 151.) 7. The theory calls in no unknown agencies. It shows that there is absolutely no more need for postulating pansperm, a peculiar "life-element," a pre-existing soul, "life entities," etc., to account for life and all life-phenomena than there was for the many kinds of elementary "atoms" which the Greeks postulated to account for matter. As a theory of life, the theory is both sufficient and necessary. Further, it appears that certain rigid demands which the theory makes, are met by answering facts of observation. One of these demands is that given certain specific conditions which beyond a doubt follow many in- juries, inevitably a neoplasm, cancer or other growth, must result. (See p. 181.) And surely, no critical but impartial reader will underrate the significance, 266 WHAT IS LIFE or corroborative value, of this agreement between demand of theory concerning neoplasms and the phenomena of cancer — the phenomena of both the abnormal "proliferation" of cells, as which (for want of a closer definition) cancer has been described by some pathologists, and of those cancers which, according to some researchers of unquestioned ability, show the presence of minute organisms. Thus it would appear that while the theory states the cause of cancer, the phenomena of cancer con- stitute a striking proof of the theory. Another demand of theory concerns specificity of species. This demand of theory is met by the fact that "species" appear to be constant. {See Chapter Seven.) The theory makes several demands of geology. (See Chapter Seven.) The easy harmony that is found to obtain between these demands and the pertinent facts of the geologic record, not improperly may be said to be in the nature of proof of the correct- ness of the theory. The theory then, plainly, is well supported. Yet there remains the imperative demand for direct ex- perimental proof. This is simply because to the trained, critical mind, absolute conviction in matters of science which may be referred to the laboratory can come only through positive and conclusive proof ON PROOF 267 that is furnished by the laboratory. And in view of the wealth of corroborative evidence of various sorts that supports the theory, it is apparent: 1 . The demand for direct physical laboratory proof of the theory is a demand that may not be denied. 2. Physical laboratory experiments to test the theory will be not only crucial as concerns the theory ^ but, since the theory treats of the basic problems of life, the research will be fundamental as well, designed to solve the primary problem of the nature of life. 3. This crucial and fundamental research will pre- pare the way and serve as a basis for much other work, since the theory opens up the entire field of inquiry into life phenomena to the quantitative method. 4. The necessary expenditure of time and money for whatever extensive and costly laboratory research is required to test the theory is well warranted. 5. Only the physical laboratory can supply the required proof. A mathematical demonstration, that is, proof, of the theory is impossible in the present state of our imperfect knowledge of the atoms that are involved. Concerning the Bohr (or the Rutherford-Bohr- Sommerfeld) atom, on which the theory is based, it is, of course, well known that it was not established mathematically, but was, as Sommerfeld put it, 268 WH AT IS LIFE **intuitiv erfasst.** However, that the *'Bohr atom" is signally successful in interpreting the spectral lines of the atoms and the chemical behavior of the ele- ments, is evident to everyone who is familiar with the problems that are involved. The modified Bohr atom today is accepted by most if not by all physi- cists and chemists. Nevertheless, it is true that the precise relations — positions and motions, of the orbi- tal electrons of the atoms of nitrogen, oxygen, sodium, etc., are not yet known. The negative electron, thanks especially to the exact measurements of Millikan, is a known constant; the value of the positive electron, too, Millikan has stated. Planck's constant has its definite value. The ratio of charge to mass is readily determined. But the normal orbits of the electrons that revolve about the nucleus of the atom are still unknown, and thus the changes caused in these orbits by the relations of the atom with other bodies are unknown; therefore the exact values of the electron that depend on position and velocity, are undetermined. Mathematical proof of the theory, then, plainly, is not possible yet. Any mathematical work lacking this knowledge of exact quantitative values, in its skillful use of variables and factors might be a thing of art, and in the ease of its presentation a veritable mathematical poem, but it could not be proof. ON PROOF 269 Fortunately, the theory does not depend on mathe- matics but on the laboratory for proof; it does not need to wait for proof until the basic data required by mathematics are determined, but it is directly amenable to crucial laboratory test. It sometimes happens that data that are lacking and that are indispensable to mathematics, are not necessary to proof by the laboratory. Thus, today the existence of the cell is one of the best-known basic facts of biology; but von Mohl's and Schleiden and Schwann's "cell-theory" never was a problem of mathematics but, of course, was established by direct experimental research. The exact manner of the formation of a system and the fact of the existence of that system are two different things. It probably would not be questioned that, though the exact paths and speeds of the orbital electrons of the atoms cannot be pointed out, and therefore certain quantitative values of even the first positive and negative electrons that collide and unite at critical positions and — pursuing a new and in- dependent path — through further collisions and unions form a new and different system (life), cannot be pointed out, the theory is none the less valid. And after all, desirable as mathematical "proof" is, it is the boast of science that most of our modern knowledge rests upon direct evidence of the labora- 270 WE AT IS LIFE tory; and only the laboratory can furnish absolutely decisive, unequivocal, and final proof on so revolu- tionary a theory as this one that asserts that life is a quantity. What constitutes the general problem that is in- volved in the question of laboratory proof of the theory, is obvious. The theory involves two essential hypotheses for which there is as yet no laboratory evidence: (1) There is a type of combination of positive and negative electrons which is distinct from the types at present recognized by physicists and chemists ; (2) this new entity is an essential constitu- ent of living matter. Thus the core of the theory is the general law of the structure of living matter. It is the affirmation that all living matter is dual, atomic-intraatomic, in composi- tion. The stability of the organism that means the living state, is determined by an intraatomic system. The intraatomic system — necessarily described as not belonging to the configuration of the atoms within which it is found, but as an immaterial quantity, that is, a quantity the units of which are not grouped after the pattern of the elements, but are organized after a different pattern, with qualities peculiarly its own — was identified as life. Together with the general law of the structure of living matter, then, are given the propositions: ON PROOF 271 1. The stability, or state of living, of the organism is due to an intraatomic system (life, or the soul). 2. The organism is a dual (atomic-intraatomic) system. 3. Life, or the soul, is a quantity — a quantity different and separable from the quantity which is the body. 4. Death is the rupture between, and the separa- tion of, the two quantities. Obviously, these concepts either do or do not answer to the facts. And the general problem of physics that is involved in the question of proof, is to establish the correctness or the erroneousness of these several propositions. The theory concerning the law of the structure of living matter is directly amenable to test. Whether it is a fact that the organism is a dual system, as described, can be experimentally determined by laboratory test. It is not a mathematical proposition that cannot be tested. Inquiring into the question of direct proof, then, it appears that amenable to laboratory test are: 1 . The general law of the structure of living matter — the description of the organism as a dual atomic- intraatomic system. 2. The definition of life — at least, so far as the description of life as a quantity is concerned. 272 WHAT IS LIFE 3. The definition of death, which describes death as the severance of the intraatomic quantity, "life," (which determines the Hving state of the organism) from the matter (or body) of the organism. With this law and these definitions established by laboratory test, it would seem that proof of the theory would be complete. For, clearly, the law of growth, the involved theory of the origin of species, and the other conclusions which are offered, all follow from the simple law of the structure of living matter, when the details of this law are carefully considered and interpreted in keeping with the established facts of atomic physics. Of course, it may be urged that since the theory afiirms the specific general condition that is necessary to initiate life, that is, to transform non-living matter into "living matter," and supplies a more or less defi- nite picture of the transition from non-life to life, the question of proof of the theory concerning the origin of life must include experimental abiogenesis. Proof of the theory as related to experimental abiogenesis, obviously can come only from the physi- cal chemistry laboratory. The physical chemist, as such, is the only person who is qualified to try to transform non-living matter into living matter in his laboratory. In his hands, the research should not be too difficult. ON PROOF 273 It would seem plain that the general law of the structure of living matter and the definition of life and of death are amenable to proof in the laboratory of the physicist. But because the problem of the structure of living matter (no less than the problem of the structure of inert matter) ultimately is a prob- lem of atomic physics, the physicist is the only one who has the tools, or who, finding his tools inade- quate, can contrive tools, to test for the law and the definitions. Of all who heretofore have testified con- cerning the problem of life in one or another of its aspects, not one has the tools for this investigation. This question of direct experimental proof of the theory then cannot be answered by the paleontol- ogist (whose facts in every way satisfy the demands of the theory), the comparative anatomist and the embryologist — who have been the chief witnesses on the question of descent; nor by the physiologist, nor the cytologist, nor the psychologist, and by neither the biochemist nor the physical chemist. The biolo- gist, as such, does not have the means of approach to the problem involved in this question of proof. Proof can be supplied only by the physicist. The work required certainly is not less difficult, but perhaps is more difficult, than any that yet has been done in physics. That living matter presents peculiar difficulties to direct research is, of course, well known. 274 W H AT I S LIFE Biophysics has been engaged for some years in experi- mentation on living matter, especially in connection with cancer research, and particularly on the effects of various rays on living matter. Thus, there is no difficulty in causing the destruction of cancer cells — where they are accessible to treatment — by X-rays or by radium rays; the difficulty consists in not also causing injury or death to normal cells. Of the fact of the difficulty of research on living matter there is no doubt. But why living matter should behave so utterly unlike non-living matter, except non-informa- tvely to assign "the state of living" as the cause, no biophysicist has attempted to say; and there then has been no clue to the cause of the peculiar dif- ficulties of research on living matter. The first of these is the difficulty that all experi- menters on protoplasm have recognized, the diffi- culty, namely, of keeping living matter alive under experimentation. "Following life in creatures we dissect, We lose it, in the moment we detect." The cause of this difficulty is found in the fact (asserted by theory) that living matter is a dual sys- tem, the constituent systems of which are in a state of delicate equilibrium, which equilibrium is easily upset. Any attack upon the dual system that de- stroijs the equilibrium to a degree that recovery of ON P ROOF 276 equilibrium is impossible, necessarily causes the sep- aration of the two systems, or the dislodgment and escape of the Z-system, from the Y-system, that is, death. The difficulty of research on living matter, ac- cording to the theory, is due, first, then, to the idelicacy of the equilibrium between the two con- stituent systems of living matter. The second difficulty is that the Z-system (the intraatomic system, life) corresponds to undeter- mined wave-lengths, which wave-lengths, however, would be found to lie outside the range of wave- lengths associated with matter. (See X-rays.) The third great difficulty of research on living mat- ter is owing to the fact (of theory) that in the living state the Z-system is screened off by the Y-system. This screening, as the theory conceives it, of course, is unlike the screening off of the nucleus, as the center, or core, of an atom, by the K-shell and other shells of the atom, yet roughly comparable to it, in that, as n research on the atom, the inner constituents of the atom cannot be made to register by the same methods that suffice for the atom as a whole, so the Z-system cannot be made to register by the same methods as the Y-system. It is a question of re- sponding to different wave-lengths, or wave-numbers. The Y-system then screens the Z-system, but screens 276 W HAT 18 LIFE it merely by reason of registering more readily (more readily, that is, according to present methods of research) . These are the chief difficulties that according to the theory are inseparable from research on pro- toplasm, and that definitely limit experimentation. However, concerning the problem of proof: It is plain that if the theory of life that has been presented is true, that is, answers to the facts, then at death the escape of the Z-system (life) from the Y-system (the body) must take place. For — once more — as life is defined as the immaterial, intraatomic sys- tem, of the organism, so death is defined as the separation and escape of this quantity from the organism. Therefore, to determine conclusively whether life is a quantity, as the theory describes, requires research upon living matter, or an organism, at the moment of death. For if the death of an or- ganism indeed means the separation of a definite quantity from the organism, then that quantity can be made to register, at least at the moment of death, by adequate means. The crucial experiment (a bi- ologist, physiologist, having prepared a suitable sub- ject) consists in causing death, and testing for and measuring the Z-system, the quantity life, that ac- cording to the theory, becomes separated from the body, the atomic system, the Y-system, at the mo- ON PROOF 277 ment of death. The experiment to be decisive, at first may be only a rather rough one — relatively speaking — and merely to establish the fact of life as a quantity. Nevertheless, the research is extremely difficult. The main problem consists in devising a method for registering a quantity (as which the theory conceives life to be) that corresponds to an undeter- mined but exceedingly small wave-lengthy or a very great wave-number. The research, of course, pre- sents a number of other difficulties, such as, for example, the necessity of distinguishing carefully between the quantities of electricity that an or- ganism may give off, due to being alive, quantities that vary according to state of health, etc., and the quantity, asserted by theory, that is life. Obviously, the research that is indicated is en- tirely different from research on the changes caused in the body by death. It is well known, and has been known for many years, that the body does not behave towards electrical stimuli in the same way after death as before death. Thus, one of the rec- ognized means of distinguishing death-like trance from actual death, is the persistence of the excita- bility of the muscles to electrical stimuli. Numerous experiments have established the fact that death causes changes in the body in respect to excitability and resistance to the electrical current. 278 WHAT 18 LIFE Obviously, too, the measurement of life that is proposed, is entirely unlike the experiments that have been made in "weighing the soul." The experi- ments of a Dr. Duncan MacDougall (of Haverhill, Mass.) who "weighed the soul," consisted in weigh- ing the human body immediately before and after death. He found a difference in weight of about six to eight ounces, and from this concluded that he had "weighed the soul." That at the moment of death, with the exhalation of the last breath, the body should lose slightly (some ounces) in weight, would seem likely from physicochemical considera- tions. However, the loss that is registered on a scale that weighs "matter" certainly is not the loss of the quantity which the theory describes as life, or the soul. One might with equal pro- priety and with equal hope of success weigh a wire after the current has been shut off, to determine something about the quantity of the current, as to weigh the human body before and after death to determine something about life, or the soul. All experiments in connection with death hereto- fore have been on the body; on tissue, nerve, muscle; on matter. There has been no research to determine whether or not death is the severance, the sub- traction, of an immaterial quantity from the or- ganism; because not a few leading men of science ON PROOF 279 have been holding and dogmatically asserting the opinion — strange to say, unwarrantedly, without any pertinent experimental data to support it — that "nothing leaves the body at death," However, it is true that never before was there a basis or warrant in science for research such as the new theory of life, based on atomic physics, is under the neces- sity of demanding. Evidently, the quantitative measurement of life hat may be expected as the result of this research, will disclose nothing of life-qualities, as a scale in a market only registers pounds without indicating whether it is a man or a barrel of flour that is weighed. The question may be raised whether, in the event that the laboratory establishes the fact of death as the separation of a quantity from the body, the quantity that leaves the body really constitutes life. Of course, if any one chooses to postulate "vital force" or "life entities" to account for life, nothing will prevent him. But it is a generally accepted principle that it is unscientific to seek a more dif- ficult "explanation" when a simple one sufiices, or to call in unknown factors when known factors answer fully. It would seem that the fact of death as the sep- aration of a quantity from the body demonstrated 280 WHAT 18 LIFE by laboratory test, will amount to conclusive proof that the quantity that escapes is life, because the establishment of this fact is the last link that is needed in the chain of evidence that supports the theory. The peculiarities of the organism, including the "truly psychical," would seem to be accounted for on the theory. The burden of proof will rest upon him who would aflfirm something else needed. That the physical laboratory can establish the propositions of the theory experimentally — if they correctly state the facts — is not open to doubt. That physical laboratory research will supply the direct experimental proof of the theory that is de- manded, reasonably may be expected; since it would appear that the theory is in entire accord with and fully supported by all known facts. Appendix Glossary Ahiogenesis. The production of living matter from non-living matter. Absolute Temperatures. Temperatures measured from absolute zero. (Absolute zero is reached at —273° centigrade, at which point the molecules are motion- less.) Acids. Acids change the color of certain indi- cators, dissolve metals, combine with bases, neutral- ize alkalis, etc. Acids are defined as compounds that in aqueous solution suffer electrolytic dissocia- tion with formation of hydrogen ions. Some acids are highly ionizable; many acids are not highly ionized in ordinary solutions. A very extensive literature treats of hydrogen ions. The accumulation of data is so great that. Dr. Leonor Michaelis says, no one person can master the entire field. See Elec- trolytic Dissociation and Metal. Adsorption. The action of a substance in con- densing and holding another substance by surface condensation (as of colloids in taking up dissolved substances). Analysis {Chemical). The determination and (or) estimation of the constituents of a compound or mixture is termed chemical analysis. There are several branches of chemical analysis: (1) Qualita- tive analysis, the process of detecting what elements are present in a compound or mixture. (2) Quantita- 281 282 WHAT 18 LIFE tive analysis, the process of determining the amounts of the elements present in a compound or mixture. (3) Proximate analysis, an analysis for the purpose of detecting and estimating the presence of certain compounds in a mixture. (4) Ultimate analysis, the determination of the elements in a compound. (5) Organic analysis, the qualitative and quantitative analysis of organic compounds, involving the deter- mination of carbon, hydrogen, nitrogen, sulphur, and the halogens (iodine, chlorine, bromine, and fluorine). (6) Combustion analysis, a method of analysis of or- ganic compounds for the determination of carbon, hydrogen (and oxygen by difference), and nitrogen. (7) Electroanalysis. This method employs the electric current to effect the separation of the constituents of a compound or mixture. (8) Spectrum analysis, the detection of elements by means of their char- acteristic spectra. Atigstrom Unit. A unit for measuring the wave- lengths of light. It is equal to one ten-thousandth of a micron. See Millimicron. Aphelion, The point in an orbit (as of a planet) farthest from the sun Qielios). By extension, in the theory of the planetary atom, the point in the orbit of an orbital electron that is farthest from the nucleus of the atom. Opposed to perihelion. Archeozoic Era. The oldest era of geological his- tory. The era of the earliest life-forms. Atmospheric Pressure. See Pressure, Atmospheric. Atomic Weight. The weight of an atom of a chemi- cal element as compared with the weight of an atom of hydrogen. The value 1 was arbitrarily assigned to the weight of the hydrogen atom because hydro- gen is the lightest of all the elements. On the basis of hydrogen equals atomic weight 1, oxygen — found to be sixteen times heavier than hydrogen — equals GLOSSARY 283 16. Because most of the elements form analyzable compounds with oxygen and few with hydrogen, oxygen =16 was adopted as the more convenient standard. (Taking 16.00 as the atomic weight of oxygen, it was later found that the atomic weight of hydrogen is 1.008.) Autolysis. The disintegration of tissues caused by the action of their own ferments. Avogadro's Constant. The number of molecules in a gram-molecule. (Symbol A^.) iV =6.062 xlO^^, It is the famous rule of Avogadro (stated in 1811) that given the same temperature and pressure, equal volumes of all gases contain equal numbers of molecules. Bacteria. Microorganisms. Bacteria were first discovered by the Dutch naturalist Anton van Leeuwenhoek in the last quarter of the seventeenth century. About a hundred years later the Danish investigator Miiller made further observations. In 1838 Ehrenberg, who discovered iron bacteria, de- scribed a large number of bacteria. The study of bacteria now ranks among the most important sub- jects of research from several approaches. The re- sults which crowned the experiments of the pathologists Robert Koch, Pasteur, and Metchnikoff, have made the widest possible appeal. Special interest also has centered in the nitrifying bacteria, which became known chiefly through the investigations of S. Winogradsky, Many hundreds of different bacteria are known and described. Bacteria are found in the alimentary canal of animals, and distributed in the air and in water, etc. Those that are injurious to the health of animals and plants are termed pathogenic. Most infectious diseases are due to bacteria; as diphtheria, to the bacillus of diptheria; typhoid fever, to the bacillus of typhoid fever, etc. Some 284 WHAT 18 LIFE bacteria are able to survive extreme cold. Paul Becquerel kept bacteria for many hours at a tempera- ture of 253°C. below zero, and yet they retained their vitality. Some bacteria or the poisons generated by them, according to E. O. Jordan, may survive boil- ing. Morphologically, bacteria are rod-shaped (ba- cilli); or in shape like twisted rods (spirella); or spherical (cocci). Methods that make possible the examination of the structure of living bacteria have been available since, some years ago, J. E. Barnard, the English optical physicist, discovered methods whereby to secure a useful magnification of 3,000 diameters, that is, the magnifying of an object twelve and one-half million times, showing detail. (Ultramicroscopes of even greater power have since been perfected; one by F. F. Lucas, with a magnification to 9,000 diameters, and one yet more powerful by W. G. Guthrie.) Bathybic Life-forms. Life-forms that inhabit the deep sea. Brownian Movement. The constant rapid and os- cillatory motion of fine particles of a substance sus- pended in a liquid. Named for the botanist Dr. Robert Brown, who first treated of the phenomenon in 1827. Brownian movement is also exhibited by the molecules of a gas. See Kinetic Theory of Gases. c. Symbol for the velocity of light. See Velocity of Light. Cancer. "Any malignant growth." Catalysis. The phenomenon in which many reac- tions that otherwise proceed very slowly have their velocities increased in the presence of certain sub- stances, which latter in most cases themselves re- main chemically unchanged. In some cases reactions are retarded. Catalyser (Catalyst). A chemical substance which GLOSSARY 285 by its presence is capable of influencing the reactions between certain other substances, while remaining chemically unchanged itself. Cathode Rays. A stream of electrons emitted from the negative pole (cathode) of a vacuum tube. Centrosome. An organ of the cell that is found at the center of greatest activity in the processes of cell-division. Chemical Action. The process in which atoms unite to form molecules or molecules are broken up into atoms. Generally, in chemical processes mole- cules are both formed and decomposed. Chemical action always is accompanied with changes in energy. Chemical Affinity, "the force which binds the atoms together in their combinations as molecules," is measured in terms of energy. The quantitative re- lations between the free energy change (change in the energy which can be obtained in the form of work) and the total energy change of a reaction in condensed systems is expressed in Nernsfs Heat Theorem. The amount of heat liberated or absorbed in a chemical reaction between given quantities of substances is termed the heat of reaction. The heat of formation is "the amount of heat liberated or ab- sorbed in the formation of one gram-molecule of a compound from its elements." Hess's Law states the amount is the same whether it is formed in one or more reactions. The heat of combustion is "the total heat liberated by the complete oxidation of a given quantity of an element or compound." And so on. (See Heat of Solution.) The idea that chemical af- finity is electrical in nature, has been entertained since the days of Sir Humphry Davy (Bakerian Lecture, 1806) and of Berzelius (1812). Faraday said that the forces of chemical affinity and electric- ity are the same. 286 WHAT IS LIFE Chemical Analysis. See Analysis, Chemical. Chemical Changes and Radioactivity, The Difference Between. In chemical changes molecules are formed or decomposed; in radioactivity atoms are disinte- grated. In chemical changes the nuclei of the atoms that are involved remain unaltered in constitution; in radioactivity the nucleus of the atom suffers the loss of one or more constituents. In chemical changes the atoms (elements) remain unchanged; in radio- activity the element is changed, transmuted, into another element. The energy liberated in radio- activity is millions of times greater than any energy liberated in chemVal changes. Chemotaxis, Positive. The property possessed by certain living cells (that are capable of spontaneous motion) of moving towards certain substances. Chromatin. The minute granules that constitute the chromoplasm (the readily stained parts) of a cell-nucleus. Coagulation. The precipitation of a colloid. In some colloids the disperse phase is separated from the dispersion medium by heat, in others by the addition of a small quantity of an electrolyte, etc. See Disperse Phase and Dispersion Medium. Compton Effect. In a very interesting and dif- ficult experiment, involving the scattering of X-rays (of molybdenum) by free electrons, the shifting of a characteristic spectral line from blue to red, indicat- ing the change of the "waves" from a shorter to a longer wave-length, or a higher to a lower frequency. This effect is produced as the result of the collision of "light-quanta" with free electrons, in which collision the light-quant transfers some of its energy to the electron, and thus with a smaller energy is changed to a lower frequency, which latter registers as a shifting of lines. The experiment was designed GLOSSARY 287 and carried out in 1923 by Arthur H. Compton, of the University of Chicago, to test the hypothesis of locahzed light-quanta. Since X-rays resemble Hght, the scattering of X-rays is a phenomenon comparable to the reflection of light. Compton proceeded on the assumption that a collision between a "light-quant" and a free electron should be governed by the general law of the conservation of energy and Newton's law of the conservation of momentum. The actual shifting of lines, and the amount of the displacement that resulted from the scattering of X-rays by free electroms, were approximately those which Compton predicted from these laws and the values belonging to a light-quant (energy hv, velocity c, etc.) and a "free" electron. The Compton experiments have been repeated and confirmed by P. A. Ross, of Stan- ford Universit}^ and others. (W. Duane, who re- peated the experiments, failed to secure the Compton effect, and secured an effect — now known as Duane's effect — that is distinct from the Compton effect. Duane therefore at first held that the Compton effect did not exist. But both effects have since been found on the same photographic plate.) The Comp- ton effect demonstrates the existence of localized "light-quanta," and thus is a directproof of Einstein's theory. Sommerfeld holds that the Compton effect promises to become the experhnentum crucis between the wave-theory of light and the quantum theory. He places the Compton effect "among the fundamental experience facts," and says "it is perhaps the most important discovery that in the present state of physics could have been made." See Spectrometer, Energy, Quantum, and X-rays. Coolidge Tube. A high-power cathode ray tube. According to Dr. Coolidge, the tube is capable of operation up to 900,000 volts. 288 WHAT 18 LIFE Coulomb's Law. The law that "the mutual force exerted by two charged bodies is directly propor- tional to the product of their charges, and inversely proportional to the square of the distance between the bodies." Crystalloids. A name given by Graham to sub- stances that in solution diffuse readily through a parchment membrane or some other septum. Dialyze. To separate crystalloids from colloids by dialysis. (In dialysis the crystalloids diffuse out through a membrane into the surrounding solvent, the colloids remaining behind.) Dielectric Constant. A term to denote the capac- ity of a substance for transmitting electrical forces or effects to another body or substance by virtue of the mere proximity to it. Disperse Phase. The dispersoid in a disperse sys- tem; that is, the colloidal particles that are suspended in a medium. See Phase and Disperse System. Disperse System. A colloidal system. Dispersion Medium. The continuous phase in a disperse system; that is, the medium in which the colloidal particles are suspended. See Phase and Dis- perse System. Electricity and Life, Early Knoivledge of. That electrical phenomena abound in life is knowledge of long standing. An early number of the Philosophical Magazine (Vol. V, Oct., 1799) contains an article entitled: "Observations on Animal Electricity, and particularly that called spontaneous." The writer, J. J. Hemmer, observes: "We are taught by many instances, both ancient and modern, that men, as well as other animals, have exhibited evident signs of electricity; although the ancients, who mention these instances, did not know to what the phenom- enon was to be ascribed." That the human body GLOSSARY 289 conducts electricity was discovered by Stephen Gray ; electricity in plants was discovered by Sir John Burdon-Sanderson (nearly sixty years ago). So- called "animal electricity" has received much atten- tion, with names such as Galvani, Peltier, Du Bois-Reymond, Tigerstedt, Ewald Hering, and Au- gustus Waller identified with the investigations. Electrochemistry. One of the branches of physical chemistry. It treats of chemical changes that deter- mine or are determined by electrical processes or phenomena. Electrokinetic. Relating to or caused by elec- tricity in motion. Electrolysis. The decomposition of a chemical compound by means of an electric current. Electrolyte. A substance (acid, base, salt) that, when present in solution, conducts the electric cur- rent. Electrolytic Dissociation. The dissociation of an electrolyte into ions when it is dissolved in water or certain other liquids. See Electrolyte. Electrolytic Solution Pressure. A term used to designate the force by virtue of which metal ions pass into solution when a metal is immersed in pure water. The metal is negatively charged and the solution positively charged. At the interface, or boundary of the metal and the solution, a layer of positive and negative charges (electrical double layer) is formed. Electron, The. Historical. The first instance on record when electricity was thought to be atomic is that of Thales of Miletus {ca. 600 B.C.) who ob- served the effect of the rubbing of amber. Benjamin Franklin, to whom we owe the terms "positive" and "negative" to designate the two kinds of electricity, was perhaps the first in modern time to advocate 290 WHAT 18 LIFE the view that electricity is atomic. In 1871 Wilhelm Weber wrote of positive and negative electrical particles. In 1873 J. Clerk Maxwell, in referring to Faraday's experiments (which showed that the quantity of electricity carried by an atom in elec- trolytic conduction is exactly proportional to the valency of the atom), spoke of a "molecule of electricity," but deemed it "extremely improbable" that the "theory of molecular charges" would be retained. In his Faraday lecture at the Royal In- stitution (1881) Helmholtz expressed the belief that electricity is atomic on the basis of Faraday's dis- coveries. However, Helmholtz did not feel prepared to embrace all electrical phenomena in his atomic view. Faraday himself did not use his own remark- able data to further an atomic theory of electricity. Dr. G. Johnstone Stoney did use the facts of ions in solutions brought to light by Faraday as his starting point, and, in 1874, developed clearly the theory of the atomic nature of electricity. He even estimated the value of the elementary electrical charge, and his estimate shows a surprising ap- proach to the later accurately determined values. Stoney also, in 1891, first suggested the word "elec- tron" (Greek elektron, amber) as a name for the "natural unit of electricity." Much theoretical work was done on the electron, notably by Sir Joseph Larmor and by H. A. Lorentz. The discovery of cathode rays for the first time in history revealed pure negative electricity. "Before we had found only electrical bodies," said P. Lenard, "but never electricity itself." But in 1897 the great Lord Kelvin, though expressing his preference for "an atomic theory of electricity," still admitted the possibility that electricity might be "a continuous homogeneous liquid." GLOSSARY 291 Then, crowning a long series of painstaking experi- ments, Sir J. J. Thomson at the Cavendish Labora- tory in Cambridge, discovered the negative electron, and measured its mean statistical charge. The work of Sir J. J. Thomson easily claims first attention. There is, as Sir Arthur Schuster says, "no doubt that Sir J. J. Thomson's experiment will be looked upon in the future as a landmark in the advance of science." Sir J. J. Thomson's epoch-making work in 1898 consisted in the experimental demonstration of the existence of units of negative electricity, whose mass is nearly 2,000 (1845) times smaller than the mass of the hydrogen atom, the lightest atom known. And, finally, Robert Andrews Millikan in Ryerson Laboratory, the University of Chicago, isolated the electron and measured the unit electrical charge. (1909.) Dr. Millikan determined the ionic charge, compared it with the frictional charge; determined the charge carried by a beta particle or the cathode ray — all have the same value. (This value is stated in the text, p. 119.) Energy, Physics. Whatever the form of the energy, potential energy, kinetic energy, electric energy, etc., energy always means "capacity for performing mechanical work"; that is, the capacity for accomplishing motion against the action of a resisting force. According to Einstein's Theory of Special Relativity, a quantity of energy represents a mass; active energy represents momentum. The mass is equal to the energy divided by c^. Einstein says: "Mass and energy are therefore essentially alike; they are only different expressions for the same thing." See Quantum. Faraday's Law of Electrical Equivalence. In elec- trolysis, the amount of a substance deposited by the same quantity of electricity always is proportional 292 WHAT IS LIFE to the equivalent weight of the substance, and is the same for all electrolytes. This quantity (termed a Faraday, or the Faraday constant, symbol F) is equal to 96,494 Coulomb, or 9,649.4 C. G. S. (or absolute electromagnetic) units. Flocculation. "The coalescence of the suspended particles of a disperse system into particles or ag- gregates of much larger size which settle out." See Disperse System. Gamete. The germ-cells that unite in fertili- zation. Gas Law. The law that at constant temperatures the product of the pressure and volume of a given quantity of gas is a constant. The volume varies inversely as the pressure. (Boyle's Law.) For the same change in temperature, the change in volume is the same for all gases. (Charles's Law. The Law of Gay-Lussac.) See Osmotic Pressure, van't Hoff Factor i, and Avogadro's Constant. Gibbs's Phase Rule. A general law that governs equilibria in heterogeneous systems. It states that "the number of degrees of freedom of a system is equal to the number of its components plus two, minus the number of phases in which it exists." It was enunciated in 1874 by Josiah Willard Gibbs. Gland. An organ the function of which is to re- move specific constituents from the blood, either as an excretion or as a secretion (as the kidneys, the liver, the sebaceous and gastric glands, etc.). Duct- less glands (as the thyroid gland, the suprarenal body, etc.) resemble true glands. Gram-atom. The atomic weight of an element stated in grams. Gram-molecule. The molecular weight of an ele- ment or compound given in grams. See Molecular Weight. GLOSSARY 298 Heat of Ionization. The heat absorbed or set free by the electrolytic dissociation of a compound in water. See Electrolytic Dissociation. Heat of Solution. The amount of heat absorbed or set free when a given quantity of a substance is dissolved in a solvent. The amount depends on the substance, the solvent, and quantity. Heliotropic. Characterized by or relating to heli- otropism. See Tropism. Hertzian Waves. "Wireless" waves. Very long electric waves. Electric waves lie below the region of the heat waves. The wave-length of the longest Hertzian waves is over a mile. They are named for their discoverer, Heinrich Hertz. Histologic. Concerned with the minute structure of tissues. See Tissue. Hydrolysis. A reaction between water and an- other compound (as salts of weak bases or weak acids) in which the second compound suffers chemi- cal decomposition and the water splits up into H and OH, one of the decomposition products com- bining with H and the other with OH. Hysteresis, Chem. A term used to denote a lag or retardation in passing into a stable condition. Hysteresis. Physics. "The tendency of a magnetic substance to persist in any state of magnetization." Isomerism. The condition of two or more (or- ganic, or carbon) compounds of having identical molecular formula (i.e., the same chemical compo- sition) but exhibiting different physical properties, and in many cases different chemical proper- ties. Compounds thus characterized are termed isomers or isomerides. Organic chemistry shows a great many cases of isomerism. Several special types of isomerism are recognized; as, stereoisom- erism (isomerism due to the different arrangement 294 WHAT IS LIFE in space of certain groups), structural isomerism, dynamic isomerism (tautomerism) , etc. See Tau- tomerism. Isotopes. The name, proposed by Soddy, for all elements that are inseparable by chemical processes. Isotopes have identical chemical properties, and the same valency. They differ in atomic weight by small amounts. The radioactive isotopes always differ in radioactive properties. Karyokinesis. Indirect cell-division. Also the series of changes exhibited by the nucleus in such cell-division. Kinetic Theory of Gases. The kinetic theory teaches that each individual molecule of a gas is endowed with motion, the velocity of which is different for the different molecules (different ele- ments), and which varies with the temperature. The kinetic theory of gases is the theory according to which all the phenomena exhibited by gases are accounted for by the motion of their constituent molecules. Kinetic Energy. The energy that belongs to a body in motion. See Energy and Quantum. Metabolism. A general term that comprises both anabolism and cataholism, and designates the changes undergone by the food taken into the animal body. In the limited sense of chemistry it means the proc- ess of the building up of more complex substances from simple substances (anabolism), or the breaking down of complex substances into simpler ones (catab- olism). In the wider view of biology it means the process of the change of the food constituents into living matter (anabolism), or the process bj'' which living matter is broken down into simpler products within a cell or an organism (catabolism). Metal. Chem. Any element that forms a base GLOSSARY 295 by combining with oxygen. (A base is a compound that in aqueous solution gives hydroxyl ions [HO].) Bases combine with acids and form salts. See Acids and Salt. Millimicron. One-thousandth of a micron. (A micron is equivalent to one-thousandth of a milli- meter, or one-millionth of a meter.) A unit for measuring light-waves. Molecular Weight. The sum of the atomic weights of all the atoms in the molecule of a compound or element. Molecule. Chem. Two or more atoms that are bound together chemically constitute a molecule. The power of atoms to unite with other atoms to form molecules is termed their "valency." The atoms of all the elements except the rare gases (helium, argon, neon, krypton, and xenon) enter into combination with other atoms to give mole- cules. When two or more atoms of the same element are united, they form a molecule of an element. When the combining atoms are of different kinds, they form a molecule of a compound. A molecule con- sists of the smallest number of atoms that will form a given chemical compound. Thus it is the smallest particle of a substance, or compound, that can have an independent existence and retain its com- position and properties . The molecule of most inor- ganic substances is light, and consists of only a small number of atoms. The molecule of most organic substances (carbon compounds) is extremely heavy. Thus, according to Julius B. Cohen, probably few proteins have a molecular weight of less than 10,000. The minimum molecular weight of hemoglobin (the solid coloring-matter of red blood-corpuscles) is estimated at about 16,000. A molecule, an octadec- apeptid (18 amino acid molecules combined), hav- 296 W H AT IS LIFE ing a molecular weight of 1213 has been built up by the German chemist Emil Fischer. This is the largest molecule ever produced by synthetic meth- ods. The polypeptides synthesized by Fischer, according to E. J. Holmyard, are very similar to the first decomposition product of the proteins, the peptones. C. W. Porter says that "no doubt this compound would have been classed as a protein if it had been discovered in nature instead of appearing as a synthetic preparation." See Chemical Action and Molecular Weight. Molecule. Physics. The structural unit in the kinetic theory. To the alteration of the position or relation of molecules all physical changes (freezing, evaporation, etc.), as distinguished from chemical changes, are due. Neoplasm. A new growth resulting from a patho- logical condition. Nereis. A sea-worm. Nulvalent. Without chemical combining power. The rare gases are nulvalent. Ooplasm. The cytoplasm of the Qgg\ i.e., the protoplasm of the egg as distinguished from the egg- nucleus. Osmotic Pressure. See Pressure, Osmotic. Oxidation. The process or state of the chemical combination of an element or compound with oxygen. Several types of reactions are covered by this term. Oxygen enters into chemical combination with most elements. Paleontology. The branch of biology that treats of fossil plants and animals. Panspermia {Cosmozoa)^ Hijpothesis of. The hy- pothesis that life-giving seeds are drifting about in space. They encounter the planets, and fill their surfaces with life as soon as the necessary conditions GLOSSARY 297 for the existence of organic beings are established. As held by Arrheniiis it teaches that when conditions on the earth had become favorable to life, life origi- nated from the action of life-sperms, or germs, which, eternal in nature and able to survive the extreme cold of interstellar space, came from space, trans- ported largely by means of radiation pressure. The view, like most other views, is related to some similar ideas of antiquity. The modern hy- pothesis of panspermia was advanced in 1865 by H. E. Richter. It was accepted by Helmholtz, by Ferdinand Cohn, and many others. Parthenogenesis. Reproduction without sexual union. Pelagic Life-forms. Life-forms that inhabit the surface of the ocean far from the land. Perihelion. The point in an orbit (as of a planet) nearest to the sun. By extension, in the theory of the planetary atom, the point in the orbit of an orbital electron that is nearest to the nucleus. Opposed to aphelion. Phase. Physical Chem. In a heterogeneous sys- tem, a uniform solid, liquid, or gas, or a mixture, a compound, or solution, that is one of the physically distinct and mechanically separable portions of the system. Photoelectric Effect. The emission of electrons caused by the influence of light. Knowledge of the photoelectric effect dates from Heinrich Hertz (1887). According to Ernest O. Lawrence and W. J. Beams, of Yale University, electrons are ejected from a metal in less than three-billion ths of a second after a ray of light strikes it. Photosynthesis. A synthetic reaction brought about by the influence of light. Planorhis. A pond snail. 298 WHAT IS LIFE Pressure, Atmospheric. The pressure of 14.7 pounds per square inch exerted by the atmosphere at sea-level. Pressure, Osmotic. If a solution is separated from the pure solvent by a semi-permeable membrane, the solvent will diffuse through the membrane into the solution, a process termed osinosis. The volume of the solution will then increase and its level will rise, thus setting up a hydrostatic pressure, termed the osmotic pressure. Chem. Diet. See van't Hoff Factor i. Protoplasm. The accepted name for "living mat- ter." It was so named by von Mohl, and called by Huxley "the physical basis of life." Quantum. The quantum of action. It is known as Planck's constant or Planck's element of action (symbol h). The sum and substance of the quantum theory is that radiant energy (sunlight and sim lar forms of energy) is emitted and absorbed by a given source only in units. The value of this unit is equal to hv, in which h, Planck's element of action, ( =6.547 XlO-" ergs) is the same for all sources, and V is the frequency of the source, varying with the source. All leading physicists now recognize h to be a universal constant. The quantum theory dates from Dec. 14, 1900, when Max Planck, professor of physics in the Uni- versity of Berlin, presented his thesis on energy quanta before the Deutsche Physikalische Gesell- schaft. Planck was led to his conclusion that the emission of energy is a discontinuous process, through his exhaustive study of black-body radiation. Five years later (in 1905) Einstein formulated the theory that light itself consists of "light-quanta," units having the value hv. Einstein evaluated the work necessary to lift an electron out of its bond in GLOSSARY 299 an atom of metal in the photoelectric effect. This value was purely theoretical. But in 1914, R. A. Millikan, as the result of elaborate experiments on the photoelectric emission of electrons, designed to test Einstein's equation, obtained results that proved Einstein's equation correct. Meanwhile Niels Bohr, in developing his now generally accepted theory of the atom, computed the value of the energy that is lost when an electron in an atom jumps from one state to another, in terms of hv. The results of cer- tain experiments by W. Duane and his collaborators corroborated this equation. A. Sommerfeld extended the laws of the distribution of quanta in atomic systems. (Of the formula which Sommerfeld worked out, Planck holds that it "is an accomplishment in every way comparable with the famous discovery of the planet Neptune, whose existence and position had been calculated by Le Verrier before it had been seen by human eye.") Millikan and Bowen's work on stripping valence electrons from atoms included the furnishing of proof of Sommerfeld's formula. With the aid of the quantum theory, and on the basis of the Bohr theory of orbits, P. Epstein and K. Schwarzschild were able to compute the value of the energy changes caused in the orbital electrons of atoms by a strong electrical field. (The so-called "Stark effect," discovered by J. Stark in 1913.) This brilliant theoretical work also was thoroughly confirmed by the spectroscope. Other verification — by J. Franck, G. Hertz, Paul D. Foote, K. T. Comp- ton, R. W. Wood, and others — has come from the field of optics, the experiments having to do with the determination of the energy values in ionization and radiation phenomena. In the X-ray field, too, experiments by De Broglie and Ellis, and other experiments by D. L. Webster supplied further 300 W H AT IS LIFE proof. A wealth of experimental work thus has proved Planck's element of action to be indeed a universal constant. However, though the quantum theory so far as h is concerned has been generally accepted as fully established, not many have been ready to accept Einstein's "extreme quantum theory" of discrete, or corpuscular, "light-quanta." Recently (1923), direct and, it would seem, convincing proof of Einstein's theory of light-quanta has been fur- nished by the Compton effect. But serious difficul- ties remain, and must be cleared up before various phenomena that have been accounted for on the wave-theory can be harmonized with the quantum theory. See Energy, Photoelectric Effect, and Comp- ton Effect. Radical. Chem. A group of atoms which enters into chemical combinations, acting as a single ele- ment, and that can pass unchanged through many chemical transformations. Salt. Chem. A compound that is produced when the hydrogen of an acid is replaced by an electro- positive element or radical. See Acid, Electrolyte, and Electrolytic Dissociation. Simiidae. An African and Asiatic family of apes. Sols. Colloidal solutions. Solution. 1. The term is generally understood to refer to the liquid phase, but solutions may also exist in the solid, and gaseous phases. A solution is "a single homogeneous phase made up of two or more components and whose compositions may vary within certain limits." In the liquid phase the liquid is known as the solvent^ and the substance dissolved in it, as the solute. 2. The process of dissolving a substance in a solvent. Sorption. A general term denoting all cases in- volving more than one of the factors, adsorption, GLOSSARY 301 diffusion, absorption, chemical reaction, electrical effects, surface tension, hydrolysis, double decom- position, and formation of solid and colloidal films. — Chem. Did. Spectrometer. A spectroscope (i.e., an optical in- strument for producing and analyzing spectra) that is fitted with special appliances for the measurement of wave-length of spectral lines, etc. Spontaneous Generation. Until about the middle of the seventeenth century, besides the belief in the doctrine of special creations, the belief in the spon- taneous generation of various life-forms, which was handed down from antiquity, was very general; in the church as well as without. When, about 1660 A.D., Francesco Redi, an Italian court physician, demonstrated that the maggots of flies grow from eggs, and not spontaneously from putrefying mat- ter, it was — to use the words of a writer in Man — "the accepted notion, that scorpions were generated by sweet basil, that frogs were brought by heavy rain, that cabbages brought forth butterflies, and that a mulberry tree could engender silkworms." But experiments to prove or disprove spontaneous generation continued to be made for two hundred years. All these experiments, however, merely had to do with sterilization. Pasteur (-1-1895) was fore- most among the men who finally disproved the old ideas. When perfect sterilization had been secured, the belief in spontaneous generation was discarded for the belief: Omne vivum ex vivo. Surface Tension. The tension of a liquid caused by the attraction exerted upon the surface mole- cules by the molecules lying underneath, and mani- festing as the tendency of all liquids to contract to the minimum area and to act as if they were sur- rounded by a very thin membrane. 302 WHAT IS LIFE Tautomerism. A term introduced by Van Laar, and used to indicate that a compound can react in two different ways. See Isomerism. Tetragrammaton. The four letters J H V H (or a variant of them) that in Hebrew texts represent the ineffable name of Jehovah. Tissue. Biol. An aggregation of similar cells and fibers that shows a definite structure and is a con- stituent part of an organ. Trauma. A wound. Tropism. The inherent tendency of an organism to respond in a specific manner to an external stimulus. Thus a heliotropic organism, unless illuminated evenly on all sides, moves either toward or away from the source of light. Tyndall {Optical) Effect. In a highly disperse system, the suspended particles are of a size too small to be visible under the microscope when they have diameters of the order of about lO^^ cms. If a powerful converging beam of white light, termed the Tyndall cone, is passed through the disperse system, the suspended particles if viewed at right angles to the direction of the beam, become visible through the light reflections of the individual par- ticles. This is called the Tyndall optical effect. True solutions do not reflect the light. Ultra-violet Rays. Light-rays that register be- yond the limit of the visible spectrum. Ultra-violet rays are the actinic, or chemically active, rays. Ultra-violet rays exert a beneficial effect on living beings from the region of the limit of the violet to about 2,900 A; rays of wave-lengths 2,990 A to 2,100 A (the middle ultra-violet) have a bactericidal action. Urease. A ferment that decomposes urea. GLOSSARY 303 Valence Electrons. Those outer electrons of an atom through the dnect agency of which the atom oombines with other atoms. VanH Hoff Factor i. Van't Hoff found that for many very dilute solutions the osmotic pressure is the same as the gaseous pressure which the substance in solution would exert in the gaseous state, at the same absolute temperature and occupying an equal volume. Van't Hoff's law of osmotic pressure states: "Equal volumes of different solutions, at the same temperature and osmotic pressure, contain equal numbers of molecules of dissolved substances." Electrolytes, because of their dissociation into ions, give greater osmotic pressures than non-electrolytes. To bring these anomalous osmotic pressures into harmony with the general finding, van't Hoff introduced the factor i, the value of which is "the ratio of the total number of ions and molecules to the total number of molecules if no dissociation had occurred." See Osmotic Pressure, Electrolyte, and Avogadro Constant. Velocity of Light (symbol c). 186,173 miles a second. (Albert A. Michelson's new figures.) All other known velocities are less than that of light; and it is held to be impossible that material veloc- ities can exceed the velocity of light. Viscosity. That property of gases, liquids and semi-fluids by reason of which they resist displace- ment, or change of the arrangement, of their con- stituent parts. X-rays, Roentgen Rays. Rays that are sent out when a stream of cathode rays (electrons) strikes the opposite walls of a vacuum tube. X-rays are similar to fight. "Today," says Sommerfeld, "we speak of Roentgen-light, and distinguish it from visible light only through its greater hardness (pene- 304. WHAT IS LIFE trability)." (Great hardness means short wave- length, or high frequency; soft rays mean greater wave-length, or lower frequency.) According to Millikan, the hardest X-rays have a wave-length of 0.1 A. It has been shown by Barkla that every ele- ment when made the anti-cathode in a discharge tube, will emit its own characteristic X-rays. These can be photographed by employing a suitable spectrometer, and the photographic plate will show lines that are characteristic for the element, and that are analogous to the spectral lines in an ordinary spectrum. The "hardness" of the X-rays increases with increase in the atomic weight of the element. Much brilliant work has been done in research upon X-ray spectra. The work of Laue, who (in 1912) in- troduced the use of the crystal grating, is a landmark in the study of X-rays. The Braggs — Sir W H. Bragg and his son W. L.Bragg — stand out for their spectrom- eter and their determination of the wave-lengths of the X-rays of various metals. Notable work has been done by Siegbahn, De Broglie, W. Duane, A. W. Hull, D. L. Webster and Harry Clark, and many others. Henry Moseley's study of the wave- lengths of the characteristic X-rays of most of the elements, resulted in his classic demonstration (1912) of the arithmetic progression in the natural series of the elements. With the aid of the modified Bohr theory of the atom, the spectral lines of the elements are slowly being deciphered, A. Sommerfeld leading in this extremely difficult research. Index Abiogenesis, experimental 252 goal of biology 14, 181 working theory of 180, 181 Acids 107, 109,281 Adaptation 240, 258 Air 102 essential to organisms 51 Allbutt, Sir Thomas Clifford 24, 31 Alpha particle 84 particles 78, 85 -ray transformation 78 Ames, Joseph S 29 Analysis, chemical 254, 281 Aristotle 199 Arrhenius, Svante 13, 34, 65, 163, 237. 297 Athenian race 194, 195 Athens 195 Artificial parthenogenesis 59, 185, 223-228, 250 Askenay 58 Aston, F.Y^ 79, 83, 85, 86, 98, 103, 124 Atmosphere 102, 236, 237 Atom 74, 82 Bohr, the 86-88, 94-97, 100, 113, 267, 268 charged 83 cubical 87 determined by nucleus 78, 99 domain of 121 dynamic 87, 88 energy changes in 95, 97 levels in 96, 97 of 83 heaviest 82 new mechanics of 95 nucleus of 86 97-100 may exist in numerous states 99 open structure of 84, 85 penetrability of 83 planetary 87, 90, 91, 94, 95, 120 and organic chemistry 91, 93 radius of 90, 106 research on 275, 304 unit in chemical changes 89 305 306 WHAT IS LIFE Atomic number 76, 86, 141 how determined 78 physics 74, 75, 119, 162, 253 ff., 258, 259-262, 273 and biologists 15, 16, 259 weight 76, 141, 282 Atoms 141 constituents of 75 76, 82 shattered 85, 103 stabiHty of 96 stripped 85, 103 Avogadro di Quaregna, Amadeo 283 constant 70, 283 Bacon, Friar Roger 31 Bacteria 51, 61, 283, 284 and colloids, similarities between 60, 61 characteristics of 60, 61 Baly, E. C. C 15 Barkla, C. J 304 Barnard, James E 284 Barrell, Joseph 27 Bases 107, 294, 295 Bateson, William 199, 208, 209, 211, 228, 258 Beams, W. J 297 Bean, Robert Bennett 191 Bechhold, H 249 Becquerel, Henri 82 Paul 284 Bergson, Henri 212 Berkeley, Hugh K 200 Bertand, Gabriel 102 Berthold, Arnold Adolph 251 Berzelius, Baron Jons Jakob 285 Beta particles 78 -ray transformation 78 Bickerton, A. W 79 Biological problem, most fundamental 14 Biology 247, 260 basic doctrine of 13, 14 final object of 175 great goal of 14, 181, 252 Biophysics 196, 197, 262, 274 Blood-relationship between man and apes 200 INDEX 307 Bloxam, Charles Loudon 106, 107, 135 Boeckh, Augustus 195 Bohn, G 59 Bohr, Niels 86, 124, 299 atom 87, 267, 268 theory of the 86-88, 94-97. 100, 299, 304 Bois-Reymond, Emil du 289 Born, Max 75, 94, 99 Bose, Sir Jagadis Chandra 174, 193, 256 Boveri, Theodor 223 Bovie, W. T 230 Bowen, I. S 85, 97, 299 Bragg, Sir William H 130, 260, 304 W. L 260,304 Brain, human 61, 165 -weight 191, 193 and intelligence 190, 191 man's and the ape's 186 Bredig, Georg 67 Broek, A. van den 76 Broglie, Louis de 299, 304 Brown, Robert 284 Brownian movement 69, 70, 284 Brown-Sequard, Charles Edward 251 Butschli, Otto 248 Bumstead, H. A 26 Burdon-Sanderson, Sir John Scott 289 Cancer, cause of 154, 181, 182, 265, 266 -cells 147 Carbohydrates 53 Carbon 52, 86, 102, 103 compounds 91 Carmichael, R. D 26 Carrel, Alexis 147, 148 Catalysis 284 Cathode rays 119, 303 tube 84, 287 Cause of cancer 154, 181, 182, 265, 266 of difference in length between man's and ape's infancy 185-188 of differences between organic and inorganic substances 176-178 of difficulties of research on living matter 274-276 308 WHAT IS LIFE Cell, the 47. 217, 248, 269 discovery of 247 specificity of 48 -theory 28, 269 Cells, artificial 248 immortality of 147-149 number of, in human body 261 Centrosome 285 Chadwick, J 85 Chamberlin, Thomas Chrowder 27, 63, 248 Chapin, Charles V 61 Chemical action 285 affinity 285 analysis 254', 281 changes and radioactivity 286 Chemistry, colloid 71, 72, 249, 250 organic 52, 87, 89. 90 physical 250, 252-256 physiological, limitations of 49 Chemotaxis. positive 184, 286 Chromatin 286 Chromosomes 230, 258, 259 Church 15 Clark, Harry 108, 304 W. Mansfield 52 Coagulation 286 Cohen, Julius B 295 Cohn, Ferdinand 297 Colloidal solutions and true solutions, how distinguished 69 Colloid chemistry 71, 72. 249. 250 state 68 Colloids and electric charges 70, 71 and crystalloids, how distinguished 67 characteristics of 60, 61 conditions for formation of 63-65 defined 66. 67, 68 Compton, Arthur H 287 Karl T 7-10, 97, 299 effect 54, 286, 287, 300 Coolidge, William D 84, 287 tube 84,287 Cosmic rays 84 Coulomb's law of electrical attraction 95, 288 INDEX 309 Crookes, Sir William 30 Crystalloids 288 Curie, Marie 82 Pierre 82 Curtis, W. C 246 Dalton, John 89 Dantec, Felix le 173 Darwin, Charles 198, 199, 200, 205, 206, 243 Darwin's Origin of Species 198 Darwinism 203 Davy, Sir Humphry 285 Death 51, 277, 278 causes of 166 Gaskell's theory of 153, 157, 165-168 Descartes, Rene 200 Descent, bases of the current theory of 208, 209 current theory of 242, 244 difficulties of the current theory of 203-213 first teaching of 199 man's 199-202, 243, 244 rejection of the current theory of 243-245 theory of 199, 202 Differences, qualitative, how caused 141 Dissociation, the ultimate in 108 Driesch, Hans 25, 28, 48, 175, 212, 220 Duane, W 287, 299, 304 Duckworth, W. L. H 201 Earth, early 63, 64, 65, 236 the 79, 80 Eddington, A. S 79 Egg, the 227, 228 specificity of 232 Ehrenberg, C. G 283 Ehrenhaft, F 104 Einstein.. Albert 29, 70, 75, 291, 298, 299, 300 theory of light-quanta 298 and Compton effect 287, 300 of relativity 29, 75, 291 Electrical stimuli and death 277 Electric charge 83, 107 on colloids 70, 71 A 310 WHAT IS LIFE Electricity 105 and life 57, 288, 289 atomic theory of 30 Electrolyte 106, 107, 289 Electrolytes 303 Electrolytic solution pressure 289 Electron 104 historical 289-291 isolation of the 291 orbits 16, 93-96 origin of the word 290 positive 85, 108 speed of the 119 value of the 119 Electronegative elements 103, 104 Electrons 75, 84 displacement of 106, 107 free 286 orbital 87, 90. 94, 106, 120, 121 positive, dislocation of 85 time required to eject 297 valence 85, 87, 90, 303 Electropositive elements 103 Element, heaviest 82 lightest 282 most abundant 102 Elements and X-rays 304 arithemetical progression of the 76 basic classi6cation of the 76, 141 electronegative 83, 103, 104 electropositive 83, 103 end of the series of the 77 found in organisms 100-103, 254 found in sun and stars 79 most abundant 103 ninety-two 78 periodic table of the 28, 77, 78, 98 prediction of 28, 141 series of the 76, 78, 98 simple 83, 103 the 75-79, 253 transmutation of 85, 86 Ellis, Carleton 53 CD 85,209 INDEX 311 Embryo 222 Embryology, experimental 219-221 Empedocles 199 Enderlein 15 Energy and light 97 and mass 75, 291 changes in atom 97 deBnition of 291 free 285 -levels in atom 96, 97 Enzymes 55, 56 Epstein, Paul S 299 Euler, Hans von 56 Evolution 73, 183, 211-214, 243 ideas of 199 of species, idea of the 198 founder of modern theory of 199 Ewald, P. P 75 Excitations and galvanometric deflections 57 Experimental abiogenesis and the Gaskell theory 180, 181, 272 embryology 219-221 method 26, 27 Fajans, Kasimir 78 Faraday, Michael 285, 290 Faraday's law of electrical equivalence 291 laws 70 Fere, Charles S 57 Fertilization 218, 219, 223, 226, 229, 230, 231 theory of 183, 184, 185 Fischer. Emil 296 Eugen 231 Martin H 62, 71 Fiske, John 25. 157 Fixity of species 206-208, 242, 243 Fodor, Andor 56 Foote, Paul D 299 Franck, J 94, 299 Franklin, Benjamin 289 Freundlich, Herbert 70. 71 Fritsch, Gustav 201, 202 Galilei 213 312 WHAT IS LIFE Gallon, Sir Francis 194 Galvani, Luigi 59, 289 Gas law 292 Gaskell, Augusta 15, 16, 17 Walter H 58 Geological record 203-206, 235-237, 239, 266 Germ-cell 48 Germ-cells 217, 218 theory of the 183-185 Gibbs, Josiah Willard 115, 292 Gibbs's phase rule 292 Gland 292 Goal of biology 14, 181, 252 Goethe, Johann Wolfgang von 249 Goodspeed, T. H 246 Graham, Thomas 68, 288 Gram-molecule 70, 292 Gray. Stephen 289 Greeks, superiority of 194-196 Growth 49, 272 Guthrie, W. G 284 Guyer, Michael F 216 Haeckel, Ernst 199, 205 Hammond, John Hays, Jr 57 Handovsky, Hans 72 Harkins, W. D 103 Hatschek, Emil 71 Heart 52, 58 Heat 285, 293 Heer, Oswald 204 Helium atom 88 Helmholtz, Baron H. von 59, 256, 290, 297 Hemmer, J. J 288 Hemoglobin, molecular weight of 295 Henderson, Lawrence J 260 Henle, Jakob 247 Heredity 48, 209, 210, 211, 214, 228-231, 258, 259 theory of 185, 231, 232, 233 Herelle, F. de 15 Hering, Ewald 170, 289 Herschel, Sir John 24 Hertwig, Oskar 183, 223 INDEX 313 Hertz, G 299 Heinrich 293, 297 Hertzian waves 293 Hess's law 285 Hittorf 30 Hoeffding, Harald 41 Hoff, H. J., van't 59, 303 Holmyard, E. J 150, 296 Hull, A. W 304 Human body, cells in 261 chemical constituents of the 100, 102 brain, shrinking of the 61 embryo, water contents of the 61 Huxley, Thomas Henry 65, 205, 298 Hydrocarbons 52, 53 Hydrogen 52, 103, 104, 105, 108, 282 atom 88, 94, 104, 105 ions 108, 116 molecule 94, 121 how split 105 nuclei 103 nucleus 85, 108 H2+-ion 109 constituents of 108 Hydrolysis 293 Hylozoism 165 Hypothesis, the place of, in science 23-25 Hypotheses, essential, of the Gaskell theory of life 270 Hysteresis 293 Immortality of cells 147-149 unicellular organisms 147 Infancy, cause of difference in length between man's and ape's. . . 185-188, 264 length of, standard for rating intelligence of a race 189-194, 196 Intelligence of a race, standard for rating 189-194, 196 Intergrades 242 Iodine 101 Ion 90 Ions, critical concentration of, postulated by the Gaskell theory of life 117, 121, 178, 235 Ionization 100, 106, 107 in liquids 106, 107, 120 of gases 106, 107 314 WHAT IS LIFE Isoelectric point 116 Isomerism 51, 293 Isotopes 83, 103, 294 Janda 217 Jeans, J. H 88 Jordan, Edwin 0 284 Kanitz, A 58 Kant, Immaniiel 35 Kaufmann, W 259 Keith, Sir Arthur 190, 252 Kelvin, Lord 32, 80, 290 Kendall, A. 1 65 Kidd, Benjamin 194 Kinetic theory of gases 294 Kirby, D 148 Klaatsch, H 200 Koch, Robert 283 Koehler, August 230 Kohlbruegge, J. H. F 198 Kossel, W 92 Kronecker, Hugo 58 Kuljabko 58 Laar, J. J. van 302 Lamarck, J. B. P 199 Langmuir, Irving 94, 99, 105 Laplace, Pierre Simon, Marquis de 27 Larmor, Sir Joseph 290 Laue, M. von 259, 304 Lavoisier, Antoine Laurent 52 Law, basic, of qualitative differences 141 Boyle's 292 Charles's 292 Coulomb's 95, 288 Faraday's, of electrical equivalence 291 Gaskell's, of the structure of living matter 154, 155, 162, 163, 270 amenable to test. . . .271, 273 and the laboratory 196 Hess's 285 Newton's, of gravitation 95 of nature 26 van't Hoff 's of osmotic pressure 303 INDEX 315 Lawrence, Ernest 0 297 Laws, Faraday's 70 similar, apply to life processes and the inorganic 57 Leduc, Stephane 173 Leeuwenhoek, Anton van 283 Lenard, P 97, 290 Le Verrier, IJrbain Jean Joseph 299 Lewis, Gilbert N 92, 177 Liesegang, Raphael Ed 64 Life, origin of 242 -processes and electrical phenomena 57 and temperature 58, 236 quantitative measurement of 34 theories about origin of, not convincing 13 not amenable to test 13 Life, the Gaskell theory of 152-157, 161, 163. 197 amenable to test 9, 16, 39, 40, 271, 272, 273 and laboratory test 270-272 and mathematical proof 267, 268, 269 and the physical laboratory 267, 273, 280 a working hypothesis 9, 180, 197 completeness of 265, 280 core of 270 critical concentration of ions postulated by 117,121,178,235 essential hypotheses of 270 opposed to panspermatism 179 prerequisites of 113 proof of 39,280 demanded 266, 267 summarization of 152, 153 test of 9,276-279 decisive 16, 279, 280 difficult 16,273,277 what will constitute proof of 272, 279, 280 Life, the Gaskell theory of, and death 153, 157, 165-168 and experimental abiogenesis 180, 181, 272 and heredity 185, 231-233 and plural origins of life. . . . 179, 233, 235, 242, 243 and quantitative methods for psychology . . 169-173 and the cause of cancer. . . .154, 181, 182, 265, 266 and the cause of man's lengthened infancy 185-188, 264 316 WHAT IS LIFE Life, the Gaskell theory of, and the cause of the difference between organic and inorganic substances 176-178 and the cause of the diflSculty of research on living matter 274-276 and the difference between living and non- living matter 173, 175, 176 and the germ-cells 183-185 and the mind 165, 169 and the organism 152, 168, 169 and the origin of life 153, 178-180, 242 and the origin of psychic prop- erties 153, 164, 165, 169 and the origin of species 153, 182, 183, 233-243 and the soul 163, 164, 271 Light 97 velocity of 303 -quanta, Einstein's theory of 298 and the Compton effect 287, 300 Lillie, Frank R 226 Ralph S 258 Linder 70 Living matter 54 and non-living matter, difference between 173, 175, 176 cause of difficulty of research on 274-276 chemical substances of 55 chemistry of 55 difficulties of research on 273-276 Gaskell's law of the structure of 154, 162, 163 state, the 153 Loeb, Jacques. . . .33, 34, 49, 51, 55, 58, 59, 62, 66, 101, 147, 167, 171, 180, 181, 185, 207, 211, 216ff., 223ff., 227, 228. 230, 241, 250ff., 257 Leo 148, 215, 216 Leonard B 85 Lohnis, Felix 15 Longevity 166 Lorentz, H. A 29, 290 Loschmidt number 70 Lucas, F. F 284 Lull, Richard Swann 201 Luschan, Felix von 200, 210 Lyman, Theodore 97 Mach, Ernst 170, 171, 256 INDEX 317 Madelung, Erwin 75 Mall, F. P 190 Mameli 53 Man and apes, blood-relationship between 200 dissimilarities between 202 similarities between 264 Man's descent 199-202, 243, 244 erect posture, cause of 188, 189 lengthened infancy, cause of 185-188 Mass 75 and energy 75, 291 Matter 105 a condition 75 amount of, in existence 79, 80 analysis of 254 and electricity, unity of 74 changed concept of 74 difference between living and non-living 173, 175, 176 living, the Gaskell law of the structure of 154, 155, 162, 163 restriction of term 74, 75, 78 Maupertuis, P. L. M. de 165 Maxwell, J. Clerk 290 Mayo, Marion J 191, 192 McClendon, J. F 185 Meltzer 58 Mendel, Gregor Johann. 33, 211, 229 Mendeleeff, Dmitri Ivanovich, 28, 141 Mendelsohn, Martin 52 Metabolism 294 Metamorphosis, induced 101 Metals 108 Metchnikoff, Elie 283 Methods, quantitative 31-34 Mettrie, Julien de la 252 Michaelis, Leonor 281 Michelson, Albert A 303 Miethe, Adolf 86 Mill, John Stuart 25, 26 MiUikan, Robert Andrews 30, 31, 32, 70, 84, 85, 87, 93, 97, 103, 119, 130, 260, 268, 291, 299, 304 Minchin, E. A 217 Minkowski, H 29 Mohl, von 247, 269, 298 318 WHAT IS LIFE Molecule 295, 296 heavy 50, 91 of chemistry 90 of organic substances 91, 295 of physics 90 Molecules 106, 141 when motionless 281 Moore, Benjamin 15, 53 Morgan, G. T 89 Thomas Hunt 211, 220, 221 Morphology 248 ff. Moseley, Henry 76, 260, 304 Motherhood, dignity of 164 Moulton, Forest Ray 27, 79 Mueller, Fritz 205 Muller, Otto Frederik 283 Muller, H. J 246 Negative charges, how acquired 83 Nernst, Walter 105, 116, 285 Newton, Sir Isaac 42, 54 Newton's law of gravitation 95 Nitrogen 53, 102, 103, 268 atom 85, 86 Non-polar substances, properties of 92 Nuclei 93 disintegrated 85 Nucleus of atom 95, 97-100 determines the atom 78, 100 Nuttall, G. H. F 200 Olson, A. R 246 Organic and inorganic substances, cause of difference between 176-178 differences between 91, 92 compounds 53 substances 50, 51, 177 peculiarities of 150, 151, 176 Organism 47. 251, 252 beginning of the 219, 222 dynamics of the 56 Gaskell theory of the 152, 168 peculiarities of the 49-51, 145-150 stability of the 50 INDEX 319 Organisms, chemical constituents of 100, 101 psychic properties of 50 unicelhilar, immortality of 147 Origin of life 242 Gaskell's theory of the 153, 178-180, 242 amenable to test 180, 181 , 272 plural 179, 233, 235, 242, 243 theories about, not amenable to test 13 not convincing 13 Origin of species, current theory of the 213 Gaskell's theory of the 153, 182, 183, 233-243 problem of the 214 Oaborn, Henry Fairfield. .63, 174, 199, 201, 206, 207, 212, 230, 236, 240, 241, 249 Osmosis 298 Osmotic forms 173 pressm-e 298 van't Hoff's law of 303 Ostwald, Wilhelm 59, 256 Wolfgang 60, 62, 66, 250, 258 Overton, James B 226 Oxidation 296 Oxygen 51, 52, 102, 268, 296 Panspermatism 13, 65, 179, 181, 252, 253, 296, 297 Parthenogenesis 215, 216, 297 artificial : ... .59, 223-228, 250 and ions 185 Paschen, F 97 Pasteur, Louis 14, 283, 301 Paton, D. Noel 262 Pauli, Wolfgang 71, 171, 182, 248, 251, 255 Pearl, Raymond 13-17, 148, 166, 211 Pearson, Karl 31, 40 Peltier, J. C. A 289 Periodic table of the elements 28, 77, 78, 98 Perrin, Jean 71, 183 Pettibone, C. J. V 55 Pfeffer, Wilhehn 248 Phase 297 rule, Gibbs's 292 Philochoras 195 Photoelectric effect 108, 297, 299 Photosynthesis 53, 54 320 WHA T IS LIFE Physical chemistry 250, 252-256 surface contacts 64 Picton ij-Q Pirsson, Louis V 205 Planck, Max 87, 120, 298, 299 Planck's constant 119^ 298, 300 value of 119 Plaskett, John Stanley 79 Pluecker, Julius 30 Plutarch I95 Poincare, Jules Henri I75 Polar substances, properties of 92 Pollaci 33 Poor, Charles Lane 29 Porter, C. W 296 Positive charges, how acquired 83 electron 85, 108, 119 Poynting, J. H 54^ 238 Problem of science, most important 7 Proof 264, 265 mathematical, of the Gaskell theory of life 267-269 of a theory 26, 36 of the Gaskell theory of life 39, 272, 279, 280 demanded 266, 267 standard of 30, 31 Proteins 54 molecular weight of 295 Proton 119 Protoplasm 48, 60, 274, 298 Prout 104 Prout's hjTDothesis 104 Psychic properties of organisms 50 origin of 153, 164, 165 Psychology and quantitative methods 169-173 Pythagoras 31 Qualitative differences, how caused 141 Quantitative methods of measurements 31-34 and psychology 169-173 Quantum 94, 96, 298 theory 87, 95, 99. 120, 298-300 Radiant energy 298 INDEX 321 Radiation 54 Radical 9O Radioactivity 78, 82, 83, 98 energy liberated in 286 Radius of atom 106 Ramsay, Sir William 237 Rare gases 295 Ratio of charge to mass 119 Ranvier, Louis Antoine 58 Redi, Francesco 301 Relativity theory, Einstein's 29, 75, 291 Reproduction 50, 149, 214, 215, 241 Respiration 56 Revolutions of thought 73, 74 Richter, H. E 297 Roentgen, Wilhelm Konrad 82 Roentgen rays 303 Rohland, Paul 61 Ross, P. A 287 Roux, W 220, 221 Russell, Henry Norris 79 Rutherford, Sir Ernest 79, 82, 85, 86, 87, 97, 103 Sachs, Julius 58, 251 Saha, M. N 79 Salt 236 Salts 52, 107 Science, most important problem of 7 Scientific activity, the fundamental 26 Schaefer, Sir Edward Albert 37, 62 Schleiden, Matthias Jakob 247, 269 Schuchert, Charles 203, 205, 236 Schuster, Sir Arthur 291 Schwann, Theodor 28, 247, 269 Schwarzschild, K 299 Sea-water 102 Seler, Eduard 210 Sex 216,217 Shaler, Nathaniel Southgate 25 Sheldon, H. H 86 Sidis, Boris 57 Siegbahn, K. M. G 304 Simiidae 200 322 WHAT IS LIFE Smith, J. D. Main 88, 89, 96 Smoluchowski, M . von 71 Soddy, Frederick 78, 174, 254, 294 Sommerfeld, Arnold 77, 82, 86, 87, 09, 104, 267, 287, 299, 303, 304 Sorption 69, 300 Soul, Gaskell's theory of the 163. 164, 271 Space 80, 81 Species, current theory of the origin of 213 fixity of 206-208, 242, 243, 266 Gaskell's theory of the origin of 153, 182, 183, 233-243 problem of the origin of 214 transmutation of 245, 246 Spectrum analysis 97, 304 Spencer, Herbert 80, 199, 258 Spontaneous generation 301 Standard of proof 30, 31 Stark, J 299 efifect 299 States of matter 105 Stieglitz, Julius 70 Stoney, G. Johnstone 290 Subelectron 104 Substances, laboratory synthesis of 89, 296 organic 50, 177 peculiarities of loO, 151, 176 Suess, Eduard 65, 203 fif Summarization of the Gaskell theory of life 152, 153 Summer, James B 56 Sunlight 54, 236, 238, 298 Surface tension 301 Svedberg, Theodcr 71 Swann, W. F. G 107 Swingle, W. W 101 Tagore, Sir Rabindranath 193 Tarchanov 57 Tautomerism 302 Temperature and life-processes 58, 236, 237 Thales 30, 33, 108, 289 Theories about origin of life not amenable to test 13 not convincing 13 Theory, Bohr's, of the atom 86-88, 94-97, 100, 267, 268, 299, 304 critical examination of a 23, 34, 35 INDEX 323 Theory, current, of the origin of species 213 definition of 25 Einstein's, of light-quanta 287, 298, 300 of relativity 29, 75, 291 Gaskell's, of life — see Life, the Gaskell theory of Theory of descent 199, 202 bases of the 208, 209 current 242, 244 difficulties of the 203-213 rejection of the 243-245 Theory of life, what is demanded of a 49 proof of a 26, 36 quantum 87, 95, 99, 120, 298-300 Thiele, T. U 23 Thomson, Sir Joseph John 30, 104, 291 Thorpe, J. F 89 Thought, revolutions of 73, 74 Tigerstedt, Robert 57, 289 Townsend, John S 30 Transmutation of elements 85, 86 of species 245, 246 Traube, Moritz 248 Tropism 302 Tropisms 251 Tyndall, John 79 effect 69, 302 Uhlenhuth 58, 200 Ultimate units 104 Ultra-violet rays 302 Unity of interpretation 256-258 Universe, extent of the 80 Uranium 82 Valence electrons 303 Valency 89, 295 Van't Hoff factor i 303 Variation 199, 208, 209-211, 229, 239 Vaulx, R. de la 216 Veraguth, Otto 57 Verworn, Max 174 Vinci, Leonardo da 31 Vries, Hugo de 59, 229 324 WHAT IS LIFE Waagen, W. H 206, 241 Walcott, Charles D 235 Wallace, Alfred Russell 199 Waller, Augustus D 57, 289 Watson, J. B 257 Weber, Wilhelm 290 Webster, D. L 299, 304 T. Arthur 53 Weimarn, P. P. von 68, 249 Weismann, August 198. 199,205 Wells, Alfred A 53 Wheeler, John M 148 Wilson, C. T. R 30 Edmund B 48, 184, 217, 219 H. A 30 H. V 149 Winogradsky, S 283 Wood, R. W 299 Woodruff, Lorande Loss 37, 48, 147 Working hypothesis 25 Gaskells theory a 9 theory of abiogenesis 180, 181 Wundt, Wilhelm 31 X-rays 82, 287. 303, 304 Zeller, Eduard 199 Zsigmondy, R. A 07, 71. 119 This book, WHAT IS LIFE by Augusta Gaskell, was designed, set, printed and bound by the Collegiate Press of Menasha, Wisconsin. The type face is Scotch Roman, Monotype No. 36, a splendid type of modern design. It composes beautifully if generously leaded and is undoubtedly the best all-around modern letter for general use. The paper is Warren's Olde Style Laid, made by the S. D. Warren Co., Boston. The binding is Holliston Cloth. With THOMAS BOOKS, careful attention is given to all details of manufacturing and design. It is the publisher's desire to present books that are satisfactory as to their physical qualities and artistic possibilities and appropriate for their par- ticular use. THOMAS BOOKS will be true to those laws of quality that assure a good name and good will.