Just as the child's mind develops so that the aid of the picture can be dispensed with, and the symbolic characters can be used in increasingly complex ways, in like manner the minds of men living in successive centuries have evolved. While an evolution of human conceptual processes in general is not necessarily implied by the evolution of the forms of written language, the former process is in part demonstrated by the latter in so far as the change from the writing of pictures to the use of conventional symbols involves an advance in human ideas of the interpretation and value of the symbols in question. A man of ancient times drew a tree to represent his conception of this object; in the writing of English we now use four letters to stand for the same object, and none of these symbols is in any way a replica of the tree. It is certainly obvious that some change in the mental a.s.sociation of symbol and object has been brought about, and to this extent there has been mental evolution.

Pa.s.sing now to other departments of human culture, we must deal in the next place with the basic "arts of life"; that is, the modes of conducting the necessary activities of every day. All men of all times, be they civilized or savage, are impelled like the brutes by their biological nature to seek food and to repel their foes. The rough stone club and ax were fashioned by the first savage men, when diminishing physical prowess placed them at a disadvantage in the compet.i.tion with stronger animals.

Smoother and more efficient weapons were made by the hordes of their more advanced descendants, some of whom remained in the mental and cultural condition of the stone age like the Fuegian, until the white travelers of recent centuries brought them newer ideas and implements. In Europe and elsewhere the period of stone gave place to the bronze and iron ages, and throughout the changing years human inventiveness improved the missile and weapon to become the bow and arrow of medieval civilization and recent African savagery. The artillery and sh.e.l.ls of modern warfare are their still more highly evolved descendants.

So it is with the dwellings of men, and the significance of the changes displayed by such things. The cave was a natural shelter for primitive man as well as for the wolf, and it is still used by men to-day. Where it did not exist, a leafy screen of branches served in its stead; even now there are human beings, like the African pygmy and the Indian of Brazil, who are little beyond the orang-outang as regards the character of the shelter they construct out of vegetation. From such crude beginnings, on a par with the lairs and nests of lower animals, have evolved the gra.s.s huts of the Zulu, the bamboo dwelling of the Malay, the igloo of the Arctic tribes, and the mud house of the desert Indians. The modern palace and apartment are merely more complex and more elaborate in material and architectural plan, when compared with their primitive antecedents.

Baskets, clay vessels, and other household articles testify in the same way to an evolution of the mental views of the people making them. The means of transportation are even more demonstrative. The wagon of the early Briton was like a rough ox-cart of the present day, evolved from the simple sledge as a beginning. In its turn it has served as a prototype for all the conveyances on wheels such as the stage-coach and the modern Pullman. The history of locomotives, employed in the first chapter to develop a clear conception of what evolution means, takes its place here as a demonstration of the way human ideas about traction have themselves evolved so as to render the construction of such mechanisms possible.

The primitive savage swimming in the sea found that a floating log supported his weight as he rested from his efforts. By the strokes of his arms or of a club in his hand, he could propel this log in a desired direction; thus the dugout canoe arose, to be steadied by the outrigger as the savage enlarged his experience. A cloth held aloft aided his progress down or across the wind, and it became an integral element of the sailing craft, which evolved through the stages of the galley and caravel to the schooner and frigate of modern times. When the steam-engine was invented and incorporated in the boat, a new line of evolution was initiated, leading from the "Clermont" to the "Lusitania" and the battleship.

The history of clothing begins with the employment of an animal's hide or a branch of leaves to protect the body from the sun's heat or the cold winds. Other early beginnings of the more elaborate decorative clothing are discerned by anthropologists in the scars made upon the arms and breast as in the case of the Australian black man, and in the figured patterns of tattooing, so remarkably developed by the natives in the islands of the South Pacific Ocean. A visit to a gallery of ancient and medieval paintings clearly shows that the conventional modes of clothing the human body have changed from century to century, while it is equally plain that they alter even from year to year of the present time, according to the vagaries of fashion.

A brief review of the "arts of pleasure," including music and sculpture and painting, demonstrates their evolution also. The earliest cavemen of Europe left crude drawings of reindeer and bears and wild oxen scratched upon bits of ivory or upon the stone walls of their shelters; the painting and sculpture of early historic Europe were more advanced, but they were far from being what Greece and Rome produced in later centuries. Indeed, the evolution of Greek sculpture carried this higher art to a point that is generally conceded to be far beyond that attained by even our modern sculptors, just as flying reptiles of the Chalk Age developed wings and learned to fly long before birds and bats came into existence.

In the field of music, the earliest stages can be surmised only by a study of the actual songs and instruments of primitive peoples now living in wild places. No doubt the song began as a recitation by a savage of the events of a battle or a journey in which he had partic.i.p.ated. In giving such a description he lives his battles again, and his simulated moods and pa.s.sions alter his voice so that the spoken history becomes a chant. From this to the choral and oratorio is not very far.

Musical instruments seem to have had a multiple origin. The ram's horn of the early Briton and the perforated conch-sh.e.l.l of the South Sea Islander are natural trumpets; when they were copied in bra.s.s and other metals they evolved rapidly to become the varied wind instruments typified to-day by the cornet and the tuba. In the same way the reed of the Greek shepherd is the ancestor of the flute and clarionet. Stringed instruments like the guitar, zither, and violin form another cla.s.s which begins with the bow and its tw.a.n.ging string. The power of the note was intensified by holding a gourd against the bow to serve as a resonance-chamber. When the musician of early times enlarged this chamber, moved it to the end of the bow, and multiplied the strings, he constructed the cithara of antiquity,--the ancestor of a host of modern types, from the harp to the ba.s.s-viol and mandolin.

The dance and the drama find their beginnings in the simple reenactment of an actual series of events. Among Polynesians of to-day the dances still retain the rhythmic beat of the war-tread measure, and many of the motions of the arms are more or less conventionalized imitations of the act of striking with a club, or hurling a spear, and other acts. To such elements many other things have been added, but the fact remains that our own formal dances, as well as the sun-dance of the Indian and the mad whirl of the Dervish, are modern products which have truly evolved.

When we turn to science and philosophy and other intellectual attainments of modern civilized peoples, it is easier to see how evolution has been accomplished, because we possess a wealth of written literature which explains the way that human ideas have changed from century to century. In these cases there can be no question that such evidences provide accurate instruments for estimating the mental abilities of the writers who produced them. We shall take up the higher conceptions of mankind at a later juncture, so at this point we need only to note that even these mental possessions, like household culture and even the physical structures of a human body, have changed and differentiated to become the widely different interpretations of the world and supernature that are held by the civilized, barbarous, and savage races of to-day.

As we look back over the facts that have been cited, and as we contemplate the large departments of knowledge about human psychology, mental development, and racial culture which these few details ill.u.s.trate, we come to realize how securely founded is the doctrine that even the human mind with all its varied powers has grown to be what it is. Indeed, it is solely due to his mental prowess that man has attained a position above that of any lower animal. And yet every human organ and its function can be traced to something in the lower world; it is a difference only in degree and not in category that science discovers. The line connecting civilized man with the savage leads inevitably through the ape to the lower mammalia possessing intelligence, and on down to the reflex organic mechanisms which end with the _Amoeba_. It is a long distance from the mechanical activities of the protozoon to the processes of human thought; yet the physical basis of the latter is a cellular mechanism and nothing more, developed during a single human life in company with all other organs from a one-celled starting-point--the human egg.

The method by which mental evolution has been accomplished is likewise demonstrable, because the factors are identical with those which bring about specific transformation in physical respects. This is to be expected, for the contention that the structures and the functions of the several organs const.i.tuting any system are inseparable has never been gainsaid.

Mental variation is real. It needs no scientist to tell us that human beings differ in intellectual qualifications and attainments, and that no two people are exactly similar even though they may be brothers or sisters. The struggle for existence or compet.i.tion on the basis of mental ability is equally real, and every day we see the prize awarded to the more fit, while those who lose are crowded ever closer to the wall. As in all other fields of endeavor, the goal of success can be attained only by adaptation, which involves an adjustment to all of the conditions of existence--to social and ethical as well as to the more expressly material biological circ.u.mstances.

Heredity of mental qualities has also been demonstrated notably by Galton, Pearson, Woods, and Thorndike, who have also shown that the strength of inheritance in the case of mental traits is approximately the same as for physical characteristics like stature and eye-color. Just as a worker-bee inherits a specific form of nervous system which cooperates with the other equally determined organic systems, wherefore the animal is forced to perform "instinctively" its peculiar specialized tasks, so the mental capacity of a human being is largely determined by congenital factors.

Upon these primarily depends his success or failure. It is quite true that environment has a high degree of influence, so great indeed that some speak of a "social heredity"; they mean by this phrase that the mental equipment of an individual is determined by the things he finds about him, or learns from others without having to invent or originate them himself.

Thus a Zulu boy acquires the habits of a warrior and a huntsman when he grows up in his native village, although he would undoubtedly develop quite different apt.i.tudes if he should be taken as an infant to a city of white men. Nevertheless his mental machinery itself would be no less surely determined by heredity, even though the things with which it dealt would be provided by an alien environment.

Our present knowledge of the nature and history of human mentality enables us to learn many lessons that have a direct practical value, although it is impossible under the present limitations to give them the full discussion they deserve. Starting from the dictum that physical inheritance provides the mechanism of intellect, education and training of any kind prove to be effective as agents for developing hereditary qualities or for suppressing undesirable tendencies. Just as wind-strewn grains of wheat may fall upon rock and stony soil and loam, to grow well or poorly or not at all according to their environmental situations, so children with similar intellectual possibilities would have their growth fostered or hampered or prevented by the educational systems to which they were subjected. But the common-sense of science demonstrates that the mental qualities themselves could not be altered _in nature_ by the circ.u.mstances controlling their development any more than the hereditary capability of the wheat grains to produce wheat would be altered by the character of the ground upon which they fell. Education and training thus find their sphere of usefulness is developing what it is worth while to bring out, and inhibiting the growth of what is harmful. That heredity in mental as well as in physical aspects provides the varying materials with which education must deal is a fundamental biological fact which is too often disregarded. It would be as futile for an instructor to attempt the task of forcing the children in a single schoolroom into the same mental mold, as it would be for a gymnasium master to expect that by a similar course of exercise he could make all of his students conform to the same identical stature, the same shape of the skull, or the same color of the eye and hair.

Before leaving the subject of mental evolution we must return to the conception of inseparable mind and matter with which the present discussion began. The whole problem of human mental evolution is solved when we accept the conclusion that the nervous mechanism and the total series of its functional operations have evolved together in the production of the human brain and human faculty. The case regarding the physical organs rests solidly on the basis of the evidences outlined in a previous chapter; the special examination of purely mental phenomena has likewise been made in the foregoing sections. Just here we must pause to give further attention to the invariable relation between the human mind and the human brain.

The personality of human consciousness consists of the current of thoughts and feelings flowing continuously as one of them rises for a time to dominance only to fade when it leads to and is replaced by another dominant element of thought. This current is affected by the messages brought to the brain by nerves from the outer parts of the body where lie the eye and ear and other sense-organs. In like manner the various non-nervous parts of the body exert their influences upon consciousness, but the affective processes, as they are called, are not as well understood as the impressions pa.s.sed inwards by the sense-organs along their nervous roadways to the central organ, the brain. But the brain is the place where the thinking individual resides; and this is one of the most important teachings of psychology, for not only does it help us to understand the evidence that human faculty has evolved, but it also inevitably brings us to consider certain vital questions of metaphysics, such as the immortality of the thinking individual after the material person with its brain ceases to exist. However, the latter question is something which does not concern us here; now it is most important to realize how completely mind is connected with the brain.

Many of the facts demonstrating this connection are matters of common knowledge. In deep and dreamless sleep the essential tissues of the brain are inactive, and in correspondence with the cessation of material events the thinking individual actually ceases to exist for a time. Any one who has ever fainted is subsequently aware of the break in the current of human consciousness when the blood does not fully supply the brain and this organ ceases to function properly; a severe blow upon the head likewise interrupts the normal physical processes, and at the same time the mind is correspondingly affected. Again, a progressive alteration of the brain as the result of diseased growth causes the mind to grow dim and incapable. Sometimes infants are born which are so deficient mentally as to be idiots, and an examination of the brain in such a case reveals certain correlated defects in physical organization. These and similar facts form the basis for the dictum that the development and evolution of the brain mean the growth and evolution of human intellect.

The further question as to the nature of the connection is interesting, but it relates to matters of far less consequence to the naturalist than the central fact of the invariable relation which does exist. Throughout the centuries many philosophers and naturalists of numerous peoples have endeavored to explain the connection in question in ways that have been largely determined by the changing states of knowledge of various periods, as well as by differences in individual temperament. Three general conceptions have been developed: first, that the material and mental phenomena _interact_; second, that they are _parallel_; and third, that they are _one_.

According to the first view, the individual thoughts and feelings forming elements in the chain of consecutive consciousness are affected by the events in the material physiology of the brain as a physical structure; the latter in turn react upon the psychical or mental elements. Thus there would be two complete series of phenomena, which are interdependent and interacting at all times, although each would be in itself a complete chain of elements.

The second interpretation is that the two series of events--namely, the physical processes of the brain and the elements of consciousness--are completely _independent_ but entirely parallel. As one writer has put the case, it is as though we had two clocks whose machinery worked at the same rate and whose relationships were such that "one clock would give the proper number of strokes when the hands of the other pointed to the hour."

But in my opinion this attempted explanation of the relation of mind to matter evades the whole question, as it does not account for the dependence of the former upon the latter, but merely a.s.sumes the existence of a more ultimate and unknown group of causes for a parallelism in the rates of operation of two series of things regarded as disconnected.

The third conception recommends itself to many on account of its greater simplicity. Formulated as the doctrine of monism, it states that the mind and its material basis are merely different _aspects_ of one and the same thing, and that there is only one series of connected elements which are known to us directly as the current of our thoughts and indirectly as the physiological processes going on mainly in the cerebrum. Thus mind is purely subjective, the brain is only mediately objective. It is because the mental and the material are so intimately related that the monist believes them to be connected as are the lungs and respiration, the hand and grasping, or the eye and the reception of visual impressions from without.

But whichever one of these explanations we choose to adopt as our own, the basic fact of primary importance is that there is an invariable dependence of human thought upon a brain comprising a highly developed cerebrum, whatever may be the ultimate nature of the way mental processes are determined by physical processes, or _vice versa_. This fact stands unquestioned and una.s.sailable; human faculty and the brain cannot be considered apart, even if they may not actually be different aspects of the same basic "mind-stuff," as Clifford calls the ultimate dual thing.

Like all of the other organs of lesser importance belonging to the nervous system, the brain is a complex of tissues which in the last a.n.a.lysis are groups of cell-bodies with their fibrous prolongations. When these cellular elements are in operation, mental processes go on; the unit of the mental process therefore is the functioning of a brain-cell. But we know that the substance of a brain-cell is the wonderful physical basis of life called protoplasm, that demanded our attention at the outset. The chemicals that go to make up protoplasm are everywhere carbon, hydrogen, oxygen, and other substances that are exactly the same outside the body as inside. It is the combination of these substances in a peculiar way which makes protoplasm, and it is the combination of their individual properties which in a real even though unknown manner gives the powers to protoplasm, even to that of a living brain-cell. Does science teach us, then, that the ultimate elements of human faculty are carbon-_ness_ and hydrogen-_ness_, and oxygen-_ness_, which in themselves are not mind, but which when they are combined, and when such chemical atoms exist in protoplasm, const.i.tute mental powers? Plain common-sense answers in the affirmative. We need not, indeed, we must not, attribute mind as such to rock salt or to the water of a stream, but we do know that salts and water and other dead substances may enter into the composition of the material brain which is the physical basis of mind.

In my opinion the individual argument renders the monistic conception of mind and matter una.s.sailable. The food that we may eat and the water we may drink are dead, and as such they display absolutely no evidence of nervous or mental processes. When they enter our bodies, they with other foods replenish the various tissues, and among these the parts of the brain. In a material sense they become actual living protoplasm, replacing the worn-out substances destroyed during our previous thinking; and their properties are combined to make brain and thought, to play for a time their part in life, and to pa.s.s back into the world of dead, unthinking things. Every one of us knows that hunger reduces our ability to think clearly and fully, and every one knows also that mental vigor is renewed when fresh supplies of nourishment reach the brain. What can be the source of mentality, if it is not something brought in from the outer world along with the chemical substances which taken singly are devoid of mind?

Scientific monism frankly replies that it is unable to find another origin.

We are thus brought to recognize, not only the continuity taught by organic evolution, but also the uniformity of the materials const.i.tuting the entire sensible world, inasmuch as the ultimate unit of all nervous phenomena is the reflex act of a protoplasmic ma.s.s, which itself is a synthesis of properties inhering in the chemical elements making up living matter. Among inorganic things the mind-stuff units are combined in relatively simple ways, and the "stuff" does not give any outward evidences of "mind" as such. Living things are almost infinitely complex as regards their chemical organization, and even in the very lowest of them we can discern a cell-reflex element which, combined with others like it, forms the unit of the compounds we call instinct, intelligence, and reason. Hence through an a.n.a.lysis of mental evolution we are enabled to form the larger conception of a continuous universe whose ultimate elements are the same everywhere.

VII

SOCIAL EVOLUTION AS A BIOLOGICAL PROCESS

We now reach a critical juncture in our study of the foundations of evolutionary doctrine, for we must pa.s.s at this point to an inquiry into the nature and origin of human social relations. In undertaking this task we may seem to leave the field which is properly that of organic evolution, and many perhaps will be unwilling to view such aspects of human life as materials for purely biological a.n.a.lysis, arrangement, and explanation. But even before the reasons for doing so may be made apparent, every one must admit that the subject of mental evolution, which comprises so large a bulk of details expressly social in their character and value, virtually compels us to scrutinize the history of the economic and other interrelationships maintained by the human const.i.tuents of civilized, barbarous, and savage communities. Language has been treated as an individual mental product, and so have the arts of life and of pleasure; but all of these things find their greatest utility in their social usage,--in their value as bonds which hold together the few or many human beings composing groups of lower or higher grade. Without discovering any other reasons we would be impelled to take up social evolution, for this process is inextricably bound up with the origin and development of all departments of human thought and action.

If now this new field is actually to be included within the scope of the laws controlling the rest of nature's evolution, two general conclusions must be established. Although no formal order need be followed, it must at some time be shown that human social relations are biological relations, to be best explained only through their comparison with the far simpler modes of a.s.sociation found by the biologist among lower orders of beings; and in the second place it must be demonstrated that identical biological laws, uniform in their operation everywhere in the organic world, have controlled the origin and establishment of even the most complex societies of men. So far no reason has been discovered by science for believing that evolution has been discontinuous, holding true only for the merely physical characteristics of humanity as a whole; and furthermore, the impersonal student of nature finds ample positive evidences showing that the basic laws of a.s.sociations of whatever grade are exactly the same. For these laws we are to seek.

Heretofore the doctrine of organic evolution has been discussed with reference to the single individual organism viewed as a natural object whose history and vital relations require elucidation. Both in the general arguments of the first few chapters and in the fifth and sixth chapters dealing with the single case of the human species, the proof has been given that all of the structural and physiological characters of any and every organic type fall within the scope of the principles of evolution, by which alone they can be reasonably interpreted. It has been unjust in a sense to ignore completely the importance of the organic relations of a social nature to which we are now to turn, because no individual can exist without having its life directly influenced, not only by other kinds of organisms, but even more intimately by other members of its own species.

In a single day's activity we who are citizens of a great metropolis are forced into contact with almost countless other lives, glancing off from one and another after influencing them to some degree, and gaining ourselves some impetus and stimulus from our longer or shorter intercourse with each of them. Our varied social relations are so many and obvious that it is quite superfluous to specify them as essential things in human life. For the very reason that they are so obvious and const.i.tute so large a part of our daily life, we are in danger of conceiving them to be exclusively human; we unconsciously regard them as different from anything to be found elsewhere and quite independent of the biological laws controlling the human unit.

On the contrary, as we trace the development of social organization from its earliest rudiments it becomes ever clearer that evolution has been continuous, and that during later ages there has been no suspension of the natural laws which earlier produced the human type of organism. The lessons we have learned are by no means to be ignored from this point forward; all of our conceptions of human biological history must be kept in mind, for anything new that we may learn is superadded to the rest,--it cannot disturb or alter the foundations already laid. It is even more important to realize that the same scientific method is to be employed which has been so fruitful heretofore. It has given us interesting facts; it has indicated the most profitable lines of attack upon one and another scientific problem; and it has demonstrated the practical value of accurate knowledge, even of information about the evolutionary process. As familiarity with the laws of human physiology enables one to lead a more hygienic and efficient life, and as the results of a.n.a.lyzing the evolution of mentality make it possible to advance intellectually with greater sureness, conserving our mental energies for effort along lines established by hereditary endowment, so now we are justified in expecting that a clear insight into the origin of our social situation and social obligations will have a higher usefulness beyond the value of the mere interest inhering in our new knowledge. Every one is necessarily concerned with social questions; never before has there been so much world-wide discussion of topics in this field. And while it is true that much good may be accomplished in utter ignorance of the past history of human inst.i.tutions and of the underlying principles which control the varied types of organic a.s.sociations, surely enlightened efforts will be more effective for good. Therefore every member of a community who is capable of thinking straight rests under an obligation imposed by nature to learn how he is related to his fellow-men; he must act in concert with them or else he forfeits his rights as a social unit. And it is his clear duty to search among the results of science for aid in ascertaining what he ought to do, and what reasons are given by evolution for the nature of his vital duties.

Despite the growing appreciation of the fundamental relation between biology and sociology, it is still far from universal. That the latter science is in a sense a division of the former is more often recognized by the biologist than by the average well-informed student of human social phenomena. The layman in sociology too often concerns himself solely with the complexities of the human problems, and he remains unaware of the manifold products in the way of communal organisms far lower in the scale of life firmly established as primitive biological a.s.sociations ages before the first human beings so advanced in mental stature that tribal unions were found good. Among insects especially the biologist finds many types of organized living things, ranging widely from the solitary individual--a counterpart of something even more primitive than the most unsocial savage now existing--up to communities that rival human civilization, as regards the concerted effect of the diversified lives of the component units. The student of the whole of living nature is favored still more in that he learns how the make-up of such a simple organism as a jellyfish displays principles underlying the structure of the whole and the interplay of the parts that are identical with principles of organization everywhere else. And all of these things can be dealt with in a purely impersonal way which is impossible when attention is restricted to the human case alone. Thus it becomes the biologist's privilege and his duty as well to place his findings before those who wish to understand the const.i.tution of human society in order that evils may be lessened and benefits may be extended. He does this so far as he may be able in full confidence that the elements and basic principles are discoverable in lower nature, just as they are in the case of the material make-up and mental const.i.tution of the single human individual.

A more explicit preliminary statement must now be given of the grounds for the belief that social evolution is but a part of organic evolution in general. Some of these reasons are not far to seek, but their cogency can scarcely be appreciated until we have examined the concrete facts of the whole biological series. Any human society selected for examination--be it a tribe, a village community, or a nation--is in last a.n.a.lysis an aggregate of human units and nothing besides. Its life consists of the combined activities of such components--and nothing else. Could we subtract the members one by one, there would be no intangible residuum after all the people and their lives had been taken away. When these simple facts are recognized, it is clear at once that the concerted activities performed by biological units cannot be anything but organic in their ultimate basis and nature; the evolution of such activities thus takes its place as a part of organic evolution.

The task of tracing out the history of social organizations of whatever grade can now be defined in precise terms: in simple words, it is to learn how the activities of the component biological units making up any a.s.sociation really differ from the vital performances of biological units existing by themselves. What is it that distinguishes a savage of antiquity from an American of to-day? The modern example is just as much an animal as the earlier type, and his physiology is essentially the same.

It is something added to the common biological qualities of all men, some relation which does not appear as such in the life of rude tribes, that makes the distinction. And it is just this superadded relation that requires explanation, as regards its exact biological value and its historic development as well.

In undertaking this difficult task, it seems best to begin with the very simplest organisms that biology knows, working upwards through the scale to man. By this course the most basic elements of organization can be discovered without having to look for them among the intricate details of our own vital situation, where secondary and advent.i.tious elements stand out in undue prominence, and where the impersonal view is well-nigh impossible. Step by step we will then work up the scale of social morphology, approaching in the natural evolutionary order that part of the subject which interests us most deeply.

Just as the construction of an edifice must begin with the fashioning of the individual brick and bolt and girder, so the evolution of a biological a.s.sociation begins with the unitary organisms consisting of single cells, like _Amoeba_. We have had occasion to discuss this animal many times in our previous studies of one or another aspect of evolution, and once again we must return to it in order to reestablish certain points that are of fundamental importance for our present purposes. Within the limits of its simple body, _Amoeba_ performs the several tasks which nature demands a living thing shall do; it feeds and respires and moves, continually utilizing matter and energy obtained from the environment for the reconstruction of its substance and replenishment of its vital powers; it coordinates the activities of its simple body, and by its reflex responses to environmental influences it maintains its adjustment to the external conditions of life. The animal does all of these things with a purely individual benefit, namely, the prolongation of its own life. While it is performing these individual tasks, it does not concern itself with anything else but its own welfare; the interests of other living things are not involved in any way, excepting in the case of other organisms that may serve the animal as food. _Amoeba_, like every other living thing, if it is to exist, must unconsciously obey the first great commandment of nature,--"_Preserve thyself_."

But its life is incomplete if it stops with the furtherance of aims that we may call purely selfish. Nature also demands that an _Amoeba_, again like every other living thing, shall perpetuate its kind. The mode by which it reproduces is ordinarily quite simple; the animal grows to a certain bulk and then it divides into two ma.s.ses of protoplasm, each of which receives a portion of the mother nucleus. Sometimes by a peculiar process it breaks up into numerous small fragments called spores, which also receive portions of the parent nucleus. The most striking feature in both kinds of reproduction in _Amoeba_ is the complete destruction of the individual parent that exists before the act and does not afterwards.

It is quite true that every part of the mother animal pa.s.ses over into one or another of its products, but it is equally true that no one of these products is by itself the original individual. So even the simplest animal we know performs a task that is not only useless to itself, but is completely destructive of itself, for nature's greater purpose of preserving the race. We can readily see why this must be so; there is no place in the world for a species whose members put individual well-being above the welfare of the race, for which the production of new generations is essential, even though the satisfaction of this demand should necessitate the sacrifice of the parent organism. We might hesitate to use the word "altruistic" in describing the self-destructive reproductive act of an _Amoeba_, because this word connotes some degree of consciousness of the existence of other than personal interests, and of the welfare of different individuals. There is no reason to believe that such conscious recognition of any natural duties is possible in the case of so low an organism. But the fact remains that the result worked out by nature is the same as though there were a definite understanding of real duties. Even this unitary organism, then, acts mechanically so as to fulfil two primal obligations, first _to itself_, through activities with individual benefit as the result, and _to the race_ by the act of reproduction which closes its individual existence and inaugurates a new generation.

The life of this example, representing the whole series of one-celled organisms, is almost infinitely simpler than that of a member of a human community, yet it reveals the beginnings of certain characteristics of the latter. Here, it is true, the natural obligations in question are not like those which are ordinarily denoted social, but it is equally true that even in this most elementary instance a living thing does not live unto itself alone. It is easy to see the value to the species as a whole of obedience to the second great law--"_Preserve thy kind_." But a little further thought makes it plain that even the performance of acts in compliance with the first mandate--"_preserve thyself_"--are not purely selfish, although their immediate value is realized as individual benefit.

Surely an organism that failed to live an efficient individual life would be ineffective in reproduction, so that from one point of view everything an animal does is tributary to the culminating act performed for the larger good of the life of the whole species. It is a nice balance that nature has worked out in _Amoeba_, as well as in all other cases, between the personal life of the individual, complete only when the final process of multiplication supervenes, and this process itself, which demands an efficient performance, even though this is destructive of the performer.