The Biologist Speaks of Life

I

WHILE engaged in the work of Mr. Hoover’s relief organizations, I saw a good deal at very close range of the behavior of men at war. I saw a constant struggle, in the case of some of these men in positions of authority, between two elements in their make-up: a brute element inherent in them as a biologically inherited vestige of prehistoric days, and a strictly human element more recently acquired and transmitted to them by education and social inheritance. Sometimes one element dictated their behavior, sometimes the other. Sometimes, unfortunately, the element of education reinforced the element of brute inheritance. The existence and influence of these two usually conflicting parts of human make-up were made especially clear and sharp because of the unwonted continuous stress of the whole situation. It was an unusual opportunity for the biologist student of human life to observe the relative strength of these two factors, which play their parts in the determination of the behavior and fate of us all. Are we, in our present evolutionary stage, more animal than human, or more human than animal? And why? And can any attempt at scientific analysis of present human make-up give us knowledge that will enable us to live more rationally, more successfully, more happily?

As detached and cool-blooded as he can possibly be in his contemplation of the make-up and the capacities and behavior of human beings, the biologist is, nevertheless, often overcome by those same feelings of awe and reverence in the face of the ‘wonders of human life,’ which overcome other less cool-blooded persons. In his laboratory and study he may assure himself that he is dealing only with an unusually complex, highly endowed, and, in every way, remarkable animal, and reassure himself, in the face of the difficulties of the biological analysis of this animal, by remembering how he has been able to reveal, and, in some measure, to explain, the make-up and capacities of other at first baffling animals. But in his home with his family, and in social intercourse with his friends and acquaintances, he sometimes loses the confidence of his laboratory hours. There is something, or many things, in all the human beings I know personally, and something in myself, which make them and me very different from the samples of the species that I study in the laboratory.

I started studying human life as a biologist by studying, first, plants, then, birds, and finally, and for a long time, insects. This might be called my undergraduate course in human life. I began my graduate course with a baby — my own — for special subject; and then, as she grew older, I turned to something easier — just men and women with whom I had less personal relations and whom I knew only as representatives of the animal species man. I found that I could not advisedly let my serious biological studies be interfered with by such incidental, but, in some ways, very confusing, things as sympathy and love and pride and hope.

II

The biologist, pays much attention to origins — often, too much. Two things can have a common or related origin and yet acquire, in the course of their development, differences that make, for all practical purposes, two very different things out of them. Quantitative differences may come to be so great that they have all the practical effect of qualitative differences. Or qualitative differences, very small, indeed, when measured by the chemist or physicist and described in the terminology of their sciences, may have very large effects in the practical relation of the substances or things exhibiting them.

Nevertheless, the biologist has good grounds for paying much attention to commonness of origin and similarities of structural make-up in his attempts to read the riddle of life — even human life. Things that have come from the same t hing, or that have a fundamental likeness of structure, are bound to have some commonness of capacity and behavior. And so the biologist, in his approach to man as a subject of scientific scrutiny, is deeply interested in the possible unraveling of the tangled and broken skein of his biological history. Whence and how has he come into being? And into being in the particular form and condition which now characterize him? Can human characteristics be found in a less complex stage of development and organization elsewhere in the world of life? And if the human body shows no radical qualitative differences from other animal bodies, what will be the significance of this to the biologist in his attempt to study and appraise human life?

As to human origin, the biologist finds no tangible evidence to support any other explanat ion t han the now familiar and widely accepted one of evolution from preëxisting lower animal kinds. For this explanation he does find what is, to him, practically convincing evidence. It is of no very great interest, certainly of no very great importance, to most of us, if we once accept the evolutionary explanation of origin, whether man is traced back to this or that particular kind of anthropoid ape, or other less anthropoid ancestor. However, when we watch a chimpanzee for some time, we come to have a hope that he is not the particular anthropoid that the biologist would ask us to recognize with any filial admiration or affection. The feeling is even more marked when the orangutan or the gorilla is the object of our curiosity. It is true, though, that, if we watch a chimpanzee long enough, a rather unsettling feeling is likely to grow on us that there is something all too familiar about him. He seems to be a caricature of some people whom we know; he behaves curiously like some children (other people’s children) whom we recall.

I had an experience with a chimpanzee once in Berlin, which sticks always in my memory. I was giving at the time, as a student of zoölogy, some special attention to anthropoids, and used to go out almost daily to the Zoölogical Gardens, where I had become acquainted with the keeper of the apes. He had a favorite chimpanzee, which he used to keep with him a great deal in his own room or office; and I got into the habit of dropping in frequently for an afternoon chat with the friendly pair. The keeper was a rather stolid sort of person, who seemed to me to possess a marked paucity of human feeling and expression. On the other hand, the chimpanzee seemed possessed of a wide range of human-like interests and feelings, and was fascinatingly varied and interesting in his expression of them. The conviction grew on me that he was almost the more human of the two.

But he rarely paid me the compliment of showing any special recognition of me or interest in me. I seemed to lack any special traits of attractiveness for him. One day, however, with the permission of the keeper, I brought an American family with me, who had with them a coal-black, extremely African negress as nurse-maid; and the chimpanzee was so animatedly friendly to this dear old mammy from the very moment of her entrance, that she soon fled, screaming with horror and fright. I shall never forget the strong impression made on me of the chimpanzee’s immediate apparent recognition of Matilda as an old acquaintance; she was the kind of human being he knew about and was interested in. Yet, as he had been brought to the Gardens as a baby and had had really no personal acquaintanceship with negroes, if he really knew Matilda, or had some sense of relationship with her, it must have been a case of biological memory.

However, the biologist does not claim that we are directly descended from the chimpanzee, or any other particular anthropoid, or particular lower kind of monkey that we know, either living or extinct. But that anthropoid and human structure are too fundamentally and minutely similar to be a result of mere coincidence or convergence, or anything else than true homology based on commonness of origin, he simply accepts as a biological fact, without regard to his feelings of friendliness or unfriendliness for chimpanzees and their immediate relatives.

This structural evidence of ancestral relationship between the anthropoids and man is added to by several other well-known kinds of likenesses, physiological, psychological, even ecological. The similarity of the chemical character of the blood of the two groups, as shown by the approximate identity of its reactions in the face of certain stimulation, — the so-called precipitin reactions, — these differing from those of the blood of other higher mammals, is a notable modern addition to the biological evidence of anthropoid and human relationships. For the same identities or close similarities in blood-character occur in other kinds of animals well known to be closely related, as the wolf and dog, or the horse and ass, and do not occur when the blood of two less closely related animals is tested.

A less important and less well-known added bit of evidence is one that came under my own observation a few years ago, during the course of some study of certain highly specialized external insect parasites of man and some other mammals. In this study it became apparent that the kinds of these parasites characteristic of and limited to men and apes are more closely related to each other than they are to parasitic kinds characteristic of the other quadrumana or of any other mammals. This points to a probable commonness of origin of the now slightly differentiated parasites of men and apes from some parasite ancestor, which may have helped to make life uncomfortable for certain common ancestors of the anthropoids and early men.

III

The biologist finds another evidence of man’s place in nature as simply one among the various groups of mammals in the conditions of the physical variation among different human races — or species, as they would probably be called by any entirely disinterested student of human kind. If an expedition of scientific gentlemen from the Academy of Sciences of Mars, say, should some day find its way to our planet, the members would doubtless report to their colleagues, on their return home, the discovery of a considerable number of earth-inhabiting different species of man, and might issue a classificatory monograph on them, not unlike one of our own monographs on the various species of bears. Our attempts at classifying the bears, you know, are attended by a good deal of discussion as to whether some of the different kinds are just different races or varieties of one species, or whether they truly represent different species. As a matter of fact, I suppose this does not much worry the bears: it worries only the scientists.

There is also some suggestive evidence about man’s position in nature to be derived from the facts of the geographical distribution of his different races. The suggestiveness comes from the interesting resemblance of the status of this distribution to that obtaining generally among the higher vertebrates. Dr. J. C. Merriam, the distinguished palæontologist and student of the history of the human species, has especially stressed this fact and its significance. Just as the distribution of the members of a group of mammals or birds indicates in fairly clear outlines a classification of these members such as would be made on a basis of their comparative structure, so the different subdivisions of human kind show a similar parallel in their distribution and structural similarities or dissimilarities.

Now, the essential point of all that has just been said concerning man’s striking structural similarity to certain higher animals, and concerning his likenesses to them in other ways, physiological, variational, and distributional, is that in these similarities the biologist finds convincing proof of man’s origin from, and definite relation to, other forms of life. And this must be ever in our minds in all our subsequent discussion. But before pointing out any of the probable special significances, to the biologist-student of human life, of the undoubted evolutionary derivation of man from lower, non-human forms of life, let us glance briefly at another aspect of the consideration of human origin, namely, the pre-history of man as a creature unmistakably man, but of much more primitive human culture than he possesses at present — a history that the discoveries and investigations of the last score of years have done more to reveal, than had all study previous to the beginning of this century.

It is to the palæontologist and historical anthropologist, that we look for facts concerning the very earliest days of man’s existence. How far back in geologic time, how long ago as estimated in years and centuries, does man seem to have lived on this earth? Where did he live? Does he first appear as scattered over all the land-surface of the globe, as he now is; or was he originally limited to a certain part or parts of it? What sort of man was he in those firstman days? What of his body? What of his habits, his culture, his relation as individual to others of his kind?

Before we listen to any of the answers, let us note that the anthropologist, in his attempts to satisfy his and our curiosity about primitive man, has a second string to his bow, in addition to that provided him primarily by the palæontologist. He recognizes in his study of the man-group, just as the general biologist does in his study of any group of animals or plants, that the present existing members of his group are not all of equal evolutionary advancement or chronology. There are always some of a type less advanced or specialized, and some of types more advanced. The less advanced are usually presumed to be older in their evolutionary origin than the more advanced; so that, although they all live now side by side and at the same time, some may be looked on as in a form or stage of greater primitiveness or antiquity, as compared with others. This is, indeed, quite true of the various living kinds, or races, of man. The native Australians, the Veddahs of Ceylon, the lost Tasmanians, the Ainus of Japan, the Bushmen of Central Africa, and several other scattered similar small groups, do represent, in their physical structure, mental capacity, and general culture, more primitive stages in human evolution than those represented by the larger Caucasian, Mongolian, Negro, and Polynesian groups, which comprise the great majority of living men.

In comparing the physical and mental character and the culture of these living primitive types, and the character and culture of various extinct types of men, as indicated by their recovered bones and articles of handiwork, the anthropologist finds such similarities, that he can refer with some confidence to these living primitive types as paralleling in many characteristics some of the more recent types of prehistoric man. He has not yet found alive that missing link between men and the anthropoids which some anthropologists have fondly imagined may still be living in unexplored regions of Africa, Asia, or Malaysia, and to find which, expeditions have occasionally been sent out, only, so far, to return empty-handed. Nor does he find any living types that can possibly be construed to parallel in their condition, or actually to be persisting remnants of, the most ancient or most primitive types of real men. But he gets nearer to understanding the life of man in t hose days when types of men now extinct were the highest types, by looking at human life as exhibited by the lowest types now living.

I must recall to your minds that geologists divide the eight hundred million years, more or less, of earth-time into a series of successive ages, characterized by differing kinds of rocks and by different floras and faunas, all, with the exception of the flora and fauna of the present age, now extinct. It is with only a few of the more recent of these ages that we need concern ourselves in our search for the geologic evidence of man’s origin. Of course, recent is a comparative term. It means, as used by geologists, anything that happened within anywhere from the last few hundred thousand to the last few million years.

In the rocks of these more recent ages, beginning with an age called Lower Oligocene, and running on up through Upper Oligocene, Lower, Mid, and Upper Miocene and Pliocene, have been found the fossil remains of numerous now extinct anthropoid apes. These have been found, not only in Asia and Africa, to which continents the few living anthropoids are now restricted, but also in Europe, which so far has been the source of all but one of the most ancient human relics. I speak of these fossils as representing numerous anthropoids; but numerous also is a comparative term; I mean by it simply considerably more kinds of anthropoids than now exist; and some of these extinct forms seem to be of a higher specialization than any now existing ones. But the rocks of none of these ages — that is, up to and including the Pliocene Age—have revealed any fossils of indubitable human creatures. The one case that may possibly constitute an exception to this statement is that of the famous Pithecanthropus, a creature of which a few bones, — to be specific, a skull-cap, a femur, and two molar teeth — probably belonging to a single individual, were found nearly thirty years ago in Java, by Dubois. These relics were found in a situation which, if it does not allow the fossils to be ascribed definitively to the Pliocene Age, in its very latest days, at least proves this relic to be an antiquity as old as the very beginning of the Pleistocene, or Glacial, Age, which is the age immediately succeeding the Pliocene, and is the most recent of the geologic series, unless the period since the last great continental glaciers existed is given a special name, such as Recent (with a capital letter), or Present, to distinguish it from that period which included the several glacial and interglacial times now recognized as comprised in the so-called Glacial Age.

Pithecanthropus has been variously hailed with joy as the long-sought missing link, regarded with scorn as an individual degenerate human reversion, or looked on, with less emotion but more judgment, as a creature of very great interest and importance in the study of man’s origin, whether it be called highest of apes or lowest of men, or whether it be excluded from the direct line of human genealogy and called an offshoot from this direct line, but one arising just before the line had culminated in undoubted human kind. In a famous discussion held around the actual fossils (brought by their discoverer to the Zoölogical Congress at Leyden in 1895), and participated in by an extraordinary gathering of the most eminent anthropologists of the world, five of these experts maintained that Pithecanthropus was an ape, seven that it was a man, and seven others that it was a transition form between man and the anthropoids. The discussion was, you see, primarily one of precise classification: there was practical agreement that this creature of uppermost Pliocene or lowest Pleistocene time was so much like an ape, and at the same time so much like a man, that it proved, if proof were still needed, that, so far as structure, at least, is concerned, the anthropoids and man differ only quantitatively and not qualitatively.

Now Pithecanthropus lived at least one million years ago; so that, if he really represents man in lowest human terms, we have had a human history on this earth of which the period since the earliest historically known civilization of Egypt and Crete is a very small fraction. But that is not necessarily to disparage the possibility of a great deal of important human history occurring during that small fraction of time. The biologist is not so foolish as to suggest that extent of time alone is a measure of the importance of epochs in human history: for most of us, that last one hundred thousandth of the period of man’s existence has a hundred thousand times more interest than all the rest; but the biologist believes that paying a little attention to prehistoric man may make the greater attention we pay to historic man more fruitful of a sounder understanding of human character, capacity, and possibility.

We seem rather to have taken for granted that Pithecanthropus was the first man, or obviously near-man, type. If this is to be our starting-point, we ask the palæontologist if he has found a more or less continuous series of human fossils running forward from Pithecanthropus, both as to time and evolutionary development, up to now. His answer inclines to be, Yes. But, in truth, he has found comparatively few actual fossils or relics of human bodies, and very considerable gaps exist in the series, both as to gradations in structure and as to time-periods represented. In fact, only one of his undoubted human relics goes back in geologic time to a period approaching that represented by Pithecanthropus.

This oldest one is known as the ‘Heidelberg Jaw,’ — because it was found in the Elsenz Valley not far from Heidelberg, — and is a lower jaw-bone, with almost all the teeth in place. Compared with the present human jaw, it is notable for its unusual size, the lack of a protruding chin, and its great strength and thickness, combined with unusual width of the region for the attachment of the muscles used in mastication. The teeth are large, but not out of proportion to the size of the jaw. The jaw-bone itself is more simian than human, but the teeth are more human than simian. Particularly notable in this respect are the canines, which are not large and long, as simian and many other mammal canines are, but small, and not extending above the level of the other teeth. However, in their size, heavy roots, and wide pulp-cavities, all the teeth present characters which distinguish them readily from human teeth of to-day.

In addition to these very earliest actual remains of the bodies of man or man-ape, there have been found, in various localities in Portugal, France, Belgium, England, and perhaps elsewhere, a large number of flaked flints, in positions which undeniably refer them to a geologic time ranging back through Pleistocene into Pliocene and probably into an even earlier age. These flaked flints, which in higher or more complex stages of flaking are commonly known in connection with all of prehistoric man’s later Pleistocene life, and even with present human life as exhibited by the more primitive living peoples, are, in their earliest forms, — known as eoliths,— the subject of much discussion. It has been shown that a certain simple flaking of flint stones can occur by natural physical means without the aid of living creatures. But many of these Pliocene, or very early Pleistocene, eoliths show such a kind of flaking, affording cutting edges and grips for firm holding in the hand, fitting them to be very simple weapons or tools, that many competent anthropologists insist that they must have been produced by living creatures, of sufficient wit and dexterity to make tools out of the material at hand most available for this purpose. Indeed, we can well imagine the first human beings picking up flints naturally flaked, and then moving on to better tools or weapons by intelligently and deliberately further flaking them, or flaking other flints, which are still found in the form of heavy, rounded pebbles of various sizes.

The great importance of these eoliths to the student of early man is that, if they are really man-made, they help substantiate the evidence of Pithecanthropus and the Heidelberg Jaw as to man’s probable origin in Pliocene time, or even earlier. If man did arise in Pliocene time, then, his antiquity is carried back by many hundred thousand years behind that later Pleistocene period in which we can be certain of his existence on the basis of undoubted human fossils.

This Pleistocene, or Glacial, Age, of which our present time may be reckoned the latest part, was a period of several hundred thousand years, characterized by a succession of great continental glaciers sweeping down from the north, probably three on this continent and four in Europe, with separating interglacial times of considerably higher average temperature, and consequent climatic amelioration. In the times of the glaciers, animals of the colder regions— as the mammoth, aurochs, and the like, — occurred all over Europe, even to its present southern boundaries; while in the warmer interglacial times, animals characteristic of lower latitudes, even considerably lower than those of present Southern Europe, replaced them. It is to this interesting age of alternating cold and warm periods that all the known actual human fossils so far found in Europe, with the exception of the probably older Heidelberg Jaw already mentioned, are assigned.

The careful study of all these Pleistocene relics of early man’s body has enabled anthropologists to distinguish certain successive types of prehistoric man, differing in some measure structurally and evolutionally; so that an older type, like Neanderthal man, distinctly shows stronger simian characters, such as smaller brain-case and more projecting orbital ridges, less chin and more jaw, more curving thighbones and more opposed great toe, than a later type, like Cro-Magnon man. And the exhaustive study of the collected thousands of specimens of early man’s handiwork have enabled anthropologists to distinguish a series of successive human cultural stages, marked by obvious differences in the variety and degree of elaboration of the weapons and tools and ornaments made and used by prehistoric man during Palæolithic, Neolithic, and the early metal ages. They even know what other animals he knew, from actual remains of these animals found with his own bones, and from crude carvings and drawings of these animals on cavewalls, made by prehistoric man himself. There are certain limestone caverns in Southern France whose walls are veritable picture galleries of prehistoric art.

Students of prehistoric man know also that many things that were a part of human life as we first know it historically formed no part of human life in Pleistocene time. Among the many thousand recovered specimens of prehistoric man’s handiwork, there is a singular paucity of variety: a few kinds are repeated over and over again with superficial changes — a fact that reveals the limited resources and variety of occupations of this early human life.

IV

Now, all this consideration of man’s origin prepares, even compels, the biological student of present-day human life to recognize many characteristics of this life as vestigial, that is, as carried over from pre-human life and from prehistoric human life. It compels him also to face the fact that, if the human body and its capacities are recognized as derived by the more or less understood processes of organic evolution from other lower animal bodies and endowments, with no introduction of super-natural means to give human life qualitatively different capacities, — supernatural ones, they might be called, — then he must not only expect to find present human life influenced by inherited carry-overs from man’s animal ancestors, but he must expect to find the human body and its behavior and its fate subject, in greater or less degree, to the influence of all the general conditions and so-called laws of biology, such as those of heredity, variation, selection, mutation, growth, the influence of environment, and the like, which apply to all living things, to all substance and capacities of substance organized as living matter.

But he must be prepared to go even further. The bio-chemists and physicists have made much progress recently in showing that many of the longaccepted familiar distinctions between living and non-living matter must be given up, and that living matter is fundamentally only a much more complex association or state of the same substances that compose other matter, and that, therefore, it is largely controlled in its behavior just as other matter is controlled, namely by physical and chemical conditions and stimuli. So that the biological student of human life must be prepared to take constantly into account the results of the investigations, and the significance of the claims, of the upholders of the physico-chemical, or mechanistic, conception of life.

Facing all this, one can see at once how necessary it is for the biological student of human life to have, if he is not to be carried off his feet at once into the camp of the cynical and hopeless complete mechanists, a wife and child at home to return to from his laboratory. If I myself am not yet convinced that all of humanism is to be dumped, together with all the rest of nature, into the common pot of chemicalism, it is chiefly due to my wife and child. Not that I cannot recognize in them the presence of bodies composed of engines, and of living tissues and organs composed of substances, mostly very complex, but at bottom made up of the same chemical elements that make up the less complex substances of non-living matter; nor that I cannot perceive in them the results of the influences of the biological laws that I find also in the various lower forms of life. But I find more in them; so much more, indeed, that, although my scientific training and knowledge urge me to look on this more as only quantitatively more, my common sense and general experience, to say nothing of my recognition of the limitations of scientific knowledge, compel me to see in them the manifestations of natural possibilities so far removed from, or in advance of, those manifestations as revealed in non-living matter or in the whole range of the rest of the world of life, that, for all practical purposes, these two human beings, and hence all others, must be looked on as possessed of at least some qualities and capacities essentially different from those found anywhere else in nature.

But this is not at all to say that I must recognize anything supernatural in these qualities. They may simply be such different and such extraordinary natural qualities, that all the study of the most widely versed and wisest student of all the rest of nature will not enable him to understand these special human qualities and capacities on the basis of this study alone. I am still not necessarily driven to look on man as something out of or beyond nature. In fact, I see so much in him that is familiar elsewhere in nature, that I should have quite as much difficulty in explaining why this is so, if he is supernatural, as I now have in trying to explain all of him in terms of the nature that is revealed in studying physics, chemistry, and the natural history of plants and the lower animals.

Altogether, then, in approaching the study of human life from the standpoint of the biologist who is not a bigot, but who is, after all, a biologist and not a theologian or metaphysician, we must take fairly into account all that the study of the rest of nature allows us to make use of in understanding certain aspects of human life, and yet must guard ourselves against the assumption that, because we understand the life of starfishes pretty well, we are sufficiently equipped with knowledge to be confident of explaining human life in terms of magnified starfish life. Even if I can declare with almost perfect certainty what will be the color of the eyes of the children of two blue-eyed parents, and with much confidence what kind of mental equipment the children of two congenitally feeble-minded parents will have, because I am familiar with a biological law discovered by a naturalist who studied heredity in garden peas, and because I have noted that this law applies equally well to certain silkworm characters and, finally, to various human traits, I am in no position to say whether your children will believe in God or not, be Republicans or Democrats or Bolsheviki, write poetry or rob banks, or live in settlement houses. I may be able to make a fair prognosis of the degreee of resistance to tuberculosis which your children will exhibit during their life, but I can make no least guess as to their probability of dying in a future war with Germany. I feel pretty certain about what will happen to the human body after death; but whether that is the whole significance of death in relation to a human being, I, not being a scientific bigot, am not at all certain. I am not a spiritist, but if I claimed to be able to say that there are and can be no spirits, I should be claiming to know the whole order of nature. And that, no naturalist, or anyone else, does know. All that the naturalist can claim is that he knows a part of the order of nature; and if some part of human life comes within that known part of the order of nature, then he insists that anyone seriously considering human life must take cognizance of this knowledge of his. Men who, in discussing the possibility of a league of nations doing away with war, argue against such possibility on the assumed premises that fighting is inherent in human nature and that human nature does not change, are not taking into account the biologist’s certain knowledge that human nature does change. The educator or prison reformer who claims that you can do anything with any man by education and environment, does not take into account the biologist’s knowledge of the unescapable influence on human fate of inherited traits. He knows that it is perfectly true that you cannot put a thousand-dollar education into a fiftydollar boy. But well-meaning people keep trying to do this all the time.

V

We have, then, to face, in our further consideration of human life from the point of view of the biologist, two rather sharply contrasted things. One thing is, that the biologist does have a certain positive knowledge of some conditions or factors that do help to determine the course of human life. The other thing is, that the course of human life is partly determined by a set of conditions which are, so far, at least, quite outside the special knowledge of the biologist. He can guess and wonder about them just as other people do, but he has no right to claim that he knows about them. If some biologists do make this claim, it must be because they are carried away by the interesting sensation of knowing anything at all about what has been so long called ‘the mystery of life.’

A famous biologist of the mechanistic-conception-of-life school once said to me, as he saw me find my way to a certain corner seat in a restaurant with bench seats along the walls, that the reason why I tried to find a corner seat was because I was positively thigmotropic — that is, because I was irresistibly impelled, as a sand flea is, to get my body into as much contact as possible with solid surroundings. The fact is that I had made an appointment with a friend to meet him in that corner.

The human being has such power of dislocating his reactions to stimuli as regards both time and space, that his behavior cannot be prophesied by any naturalist with ever so complete knowledge of the reflexes and tropisms exhibited by very simple animals. That is, the inevitable and immediate responses of Paramœcium, or house-flies, or of just-hatched spiderlings, to physical and chemical stimuli, which responses, in sum, compose their behavior, may have their vestiges in man, and do have certain parallels, as in the behavior of the internal organs and certain external reflexes. But, for the most part, man turns toward or away from light, or finds a seat in a corner or away from the roomwalls, because he is influenced by factors very different from simple physical and chemical ones — factors which may be of a week ago or a mile away. It is these non-mechanistic factors or conditions in human life, and their results, that constitute that part of human life — which is peculiarly the human part—that the biologist must hesitate to be dogmatic about. Yet this part must have a seizing interest for him— that is, if he is himself human and not made over, by too much association with Parumœcium, to be more like his Protozoan pet than like the rest of his own species.

In our continuing consideration of human life, therefore, as the biologist sees it, we shall not hesitate to touch upon any of the phenomena and problems presented by this life, whether they be clearly within the province which the biologist can pretty confidently claim as his, or in that other province which less clearly belongs to him, but which he may believe he has at least as much right as anyone else to venture into.

{The Biologist and Death will be the subject of Mr. Kellogg’s next paper.)