So far our attention has been directed to the evolution of the human body, now we must consider that of the human mind. In seeking through the animal kingdom for the probable ancestor of man in his bodily aspect, we were drawn irresistibly to the ape tribe, as the only one that made any near approach to him in structure. In considering the case from the point of view of mental development we find a similar irresistible drawing toward the apes, as the most spontaneously intelligent of the mammalia. While many of the lower animals are capable of being taught, the ape stands nearly alone in the power of thinking for itself, the characteristic of self-education.

Innumerable testimonials could be quoted from observers in evidence of the superior mental powers of the apes. Hartmann says of them that "their intelligence sets them high above other mammals," and Romanes that they "certainly surpass all other animals in the scope of their rational faculty." It is scarcely necessary here to give extended examples of ape intelligence. Hundreds of instances are on record, many of them showing remarkable powers of reasoning for one of the lower animals. The ape, it is true, is not alone in its teachableness. Nearly all the domestic animals can be taught, the dog and the elephant to a considerable degree. And evidences of reasoning out some subject for themselves now and then appear in the domesticated species; but these are rare instances, not frequent acts as in the case of the apes.

The apes, indeed, rarely need teaching. They observe and imitate to an extent far beyond that displayed by any others of the lower animals, and the more remarkable from the fact that in nearly every instance the animals concerned began life in the wild state, and had none of the advantages of hereditary influence possessed by the domesticated dog and horse. Among the most interesting examples of spontaneous acts of intelligence of the ape tribe are those related by Romanes, in his "Animal Intelligence," of the doings of a cebus monkey, which he kept for several months under close observation in his own house. Instead of selecting general examples of ape actions, we may cite some of the doings of this intelligent creature.

The cebus did not wait to be shown how to do things, but was an adept in devising ways to do them himself. He had the monkey love of mischief well developed, and not much that was breakable came whole from his hands. When he could not break an egg cup by dashing it to the ground, he hammered it on the post of a brass bedstead until it was in fragments. In breaking a stick, he would pass it down between a heavy object and the wall, and break it by hanging on its end. In destroying an article of dress, he would begin by carefully pulling out the threads, and afterward tear it to pieces with his teeth. His nuts he broke with a hammer precisely as a man would have done and without being shown its use. Ridicule was not pleasant to him; he strongly resented being laughed at, and would throw anything within reach at his tormentor and with a skill and force not usual with monkeys. Taking the missile in both hands and standing erect, he would extend his long arms behind his back and hurl the article by bringing them forcibly forward.

If any object he wanted was too far away to reach, he would draw it toward him with a stick. Failing in this, he was observed to throw a shawl back over his head, and then fling it forward with all his strength, holding it by two corners. When it fell over the object, he brought this within reach by drawing in the shawl. In his gyrations, the chain by which he was fastened often became twisted around some object. He would now examine it intently, pulling it in opposite ways with his fingers until he had discovered how the turns ran. This done, he would carefully reverse his motions until the chain was quite disentangled.

The most striking act of intelligence told of this creature was his dealings with a hearth-brush which fell into his hands, and of which the handle screwed into the brush. It took him no long time to find out how to unscrew the handle. When this was achieved, he at once began to try and screw it in again. In doing so he showed great ingenuity. At first he put the wrong end of the handle into the hole, and turned it round and round in the right direction for screwing. Finding this would not work, he took it out and tried the other end, always turning in the right direction. It was a difficult feat to perform, as he had to turn the screw with both hands, while the flexible bristles of the brush prevented it from remaining steady. To aid his operations he now held the brush with one foot, while turning with both hands. It was still difficult to make the first turn of the screw, but he worked on with untiring perseverance until he got the thread to catch, and then screwed it in to the end. The remarkable thing was that he never tried to turn the handle in the wrong direction, but always screwed it from left to right, as if he knew that he must reverse the original motion. The feat accomplished, he repeated it, and continued to do so until he could perform it easily. Then he threw the brush aside, apparently taking no more interest in that over which he had worked so persistently. No man could have devoted himself more earnestly to learn some new art, and become more indifferent to it when once learned. These are a few only of the many acts of intelligence observed by Mr. Romanes in the doings of this animal. They will suffice as examples of what we mean by spontaneous intelligence. The cebus did not need to be shown how to do things; it worked them out for itself much as a man would have done, performing acts of an intricacy far beyond any ever observed in other classes of animals in captivity. It may be said further that the displays of spontaneous intelligence shown by dogs, cats, and similar animals have usually been intended in some way for the advantage of the animal; few or none are on record which indicate a mere desire to know without ulterior advantage; no persevering effort, like that with the brush, which is purely an instance of self-instruction.

Examples of intelligence of this advanced character could be cited from observation of monkeys of various species. The anthropoid apes have not been brought to any large extent under observation, but are notable for their intelligence in captivity. It is not easy to observe them in a state of nature, and nearly all we know is that the orang makes itself a nightly bed of branches broken off and carefully laid together, and is said to cover itself in bed with large leaves, if the weather is wet. The chimpanzee has a similar habit, and the gorilla is said to build itself a nest in which the female and the young sleep, the old male resting at the foot of the tree, on guard against their dangerous foe, the leopard.

It is the young animals of these species which are the most social and docile and most approach man in appearance. As they grow older, their specific characters become more marked. Fierce and sullen as is the old gorilla, the young of this species is playful and affectionate in captivity and is given to mischievous tricks. The one that was kept for a time in Berlin showed much good-nature, playfulness, and intelligence, and some degree of monkey mischievousness. It was very cunning in carrying out its plans, particularly in stealing sugar, of which it was very fond.

The chief examples of anthropoid intelligence are told of the chimpanzee, which has been most frequently kept in captivity. It is usually lively and good-tempered and is very teachable. Some of the stories of its intelligence may be apocryphal, as those told by Captain Grandpre of a chimpanzee which performed all the duties of a sailor on board ship, and of one that would heat the oven for a baker and inform him when it was of the right temperature. But there are authenticated stories of chimpanzee intelligence which give it a high standing in this respect among the lower animals.

The emotional nature of the ape is also highly developed. It displays an affection equal to that of the dog, and a sympathy surpassing that of any other animal below man. The feeling displayed by monkeys for others of their kind in pain is of the most affecting nature, and Brehm relates that in the monkeys of certain species kept under confinement by him in Africa, the grief of the females for the loss of their young was so intense as to cause their death. More than once an ardent hunter has seen such examples of tender solicitude among monkeys for the wounded and of grief for the dead as to resolve never to fire at one of the race again.

James Forbes, in his "Oriental Memoirs," relates a striking instance of this kind. One of a shooting party had killed a female monkey in a banian tree, and carried it to his tent. Forty or fifty of the tribe soon gathered around the tent, chattering furiously and threatening an attack, from which they were only diverted by the display of the fowling-piece, whose effects they seemed perfectly to understand. But while the others retreated, the leader of the troop stood his ground, continuing his threatening chatter. Finding this of no avail, he came to the door of the tent, moaning sadly, and by his gestures seeming to beg for the dead body. When it was given, he took it sorrowfully up in his arms and carried it away to the waiting troop. That hunter never shot a monkey again.

This deep feeling for the dead is probably not common among monkeys. The gibbon, for instance, is said to take no notice of the dead. It is, however, highly sympathetic to injured and sick companions, and this feeling seems common to all the apes. No human being could show more tender care of wounded or helpless companions than has often been seen in members of this affectionate tribe of animals.

Without giving further examples of the intelligence and sympathy of the apes, we may say that they possess in a marked degree the mental powers to which man owes so much, viz. observation and imitation. The ape is the most curious of the lower animals—that is, it possesses the faculty of observation in an unusual degree. What we call curiosity in the ape is the basic form of the characteristic which we call attention or observation in man. Its seeming great activity in the ape is what might naturally be expected in an observant animal when removed from its natural habitat to a location where all around it is new and strange. Man under like circumstances is as curious as the ape, while the latter in its native trees probably finds little to excite its special attention. In both man and the ape it needs novelty to excite curiosity.

Again, the ape is imitative in a high degree. This faculty also it does not share with the lower animals, but does with man, imitation being one of the methods by which he has attained his supremacy. Observation, imitation, education, are the three levers in the development of the human intellect. The first two of these the ape possesses in a marked degree. It is susceptible also to the last, being very teachable. Education certainly exists to some extent among the apes in their natural habitat, perhaps to as great an extent as it did in primitive man. In the latter case it is doubtful if there was much that could be called designed education, the young gaining their degree of knowledge by observing and imitating their elders. The same is certainly the case among the apes.

We may reasonably ask what there is in the life and character of the apes to give them this mental superiority over the remaining lower animals. It is certainly not due to the arboreal life and powers of grasp of these animals, for in those respects they resemble the lemurs, which are greatly lacking in intelligence. Whether the monkeys emerged from the lemurs or the two groups developed side by side is a question as yet unsettled; at all events they are closely similar in conditions of existence. Yet while the monkeys are the most intelligent and teachable of animals, the lemurs are among the least intelligent of the mammalia. There is here a marked distinction which is evidently not due to difference of structure or habitat, and must have its origin in some other characteristic, such as difference in life habits.

There is certainly nothing in the diet of the ape to develop intelligence. The frugivorous and herbivorous animals do not need cunning and shrewdness to anything like the extent necessary in carnivorous animals. They do not need to pursue or lie in wait for prey; and they escape from their enemies mainly through strength, speed, concealment, or other physical powers or methods. Escape may occasionally develop mental alertness, but does not usually do so. Certainly if the alert, watchful, suspicious habits of the apes are due to the requisite of avoiding dangerous enemies, we might naturally look for similar habits in the lemurs, which are similarly situated. And if we consider the wide distribution of the apes throughout the tropics of both hemispheres, and their great diversity in species and condition, it seems very unlikely that in all these localities their relations with other animals would be such as to develop the mental alertness which they so generally display. The fact appears to be that, while this may be a cause, it is not a leading cause, of mental development in animals, and that we must seek elsewhere for the origin of animal intelligence.

Research, indeed, leads us to examples of intelligence where we should least expect to find it. Among the mammalia we perceive one marked example in the beavers, the only one in the great class of the rodents, with their nine hundred or more of species. But we must go still lower, to the insects, for the most striking examples, finding them alone in the ants, the bees, and the termites, among the vast multitude of insect forms. Less marked instances appear in the elephants, in some of the birds, and in certain other gregarious animals.

From these examples, and what is elsewhere known of animal intelligence, one broad conclusion may be drawn, that all the strikingly intelligent animals are strongly social in their habits, and that no decided display of intelligence is to be found among solitary species. This conclusion becomes almost a demonstration in the case of the ants and bees. The ants, for instance, comprise hundreds of species, spread over most of the world, mainly social, but occasionally solitary. The social species, while varying greatly in habit, all display powers of intelligence, and these so diversified as to indicate many separate lines of evolution. The solitary ants, on the contrary, manifest no special intelligence, and do not rise above the general insect level. The same may be said of the bees. The hive bee, the most communal in habit, shows the highest traits of intelligent activity. The bees which form smaller groups and the social wasps stand at a lower level, and the solitary bees and wasps sink to the ordinary insect plane. We arrive at like conclusions from observation of the social termites, or white ants, some species of which are remarkable for their intelligent cooeperation and division of duties.

Examples similar in kind may be drawn from the vertebrates. Among the birds there are none more quick-witted than the social crows, none with less display of intelligence than the solitary carnivorous species. Birds are rather gregarious than social. There are few species whose association is above that of mere aggregation in flight. Those more distinctively social usually have special habits which indicate intelligence—as in the often cited instances of their seemingly trying and executing delinquents. Among the carnivorous mammals the social dog or wolf tribe displays the intelligent habit of mutual aid. The horses, oxen, deer, and other gregarious hoofed animals have a degree of division of duties, but their intelligence is of a lower grade than that of the dogs and the elephants. On the whole, it may be affirmed that the social habit is frequently accompanied by instances of special intelligence to which we find no counterpart among the solitary forms, and that the highest manifestations of intelligence in the lower animals are found in those forms which possess communal habits, as the ants, bees, termites, and beavers.

One important characteristic of the communal animals is that they become mentally specialized. They round up their powers, build barriers of habit over which they cannot pass, perform the same acts with such interminable iteration that what began as intellect sinks back into instinct. Each individual has fixed duties and is confined within a limited circle of acts, whose scope it cannot pass, or only to the minutest extent.

The non-communal social animals, on the contrary, are not thus restricted. Their intelligence is of a generalized character, and is capable of developing in new channels. None are tied down to special duties, each possesses the full powers of all, and they are thus more open to a continued growth of the intellect than the communal forms. To this class belongs the ape. Its intelligence is general, not special; broadly capable of development, not narrowed and bound in by the limitation of certain fixed and special duties.

The suggestions above offered point to three grades of community among animals, which may be designated the communal, the social, and the solitary. Among these there are, of course, many stages of transition from one to the other. The specially communal, including the ants, bees, termites, and beavers, are those in which there is almost a total loss of individuality, each member working for the good of the community as a unit, not for its personal advantage. The result consists in organized industries, division and specialization of duties, a common home, food stock, etc. At a lower level in animal life, that of the hydroid polyps, communism has become so complete that the community has grown into an actual individual, the members not being free, but acting as organs of an aggregate mass, in which each performs some special duty for the good of the community.

The social animals differ from the communal in that the individuality of the members is fully preserved. There is some measure of work for the group, some degree of mutual aid, some evidence of leadership and subordination, but these are confined to a few exigencies of life, while in most of the details of existence each member of the group acts for itself. The solitary animals are those which do not form groups larger than that of the family, and into whose life the principle of mutual aid, outside the immediate family relations, does not enter. Each acts for itself alone, and intercourse between the individuals of the species is greatly restricted.

The advantages of social habits among animals are evident. There is excellent reason to believe that all animals, and especially such advanced forms as the vertebrates and the higher arthropods, have some power of mental development, some facility in devising new methods of action to meet new situations. Though their reasoning power may be small, it is not quite lacking, and many examples of the exercise of the faculty of thought could be cited if necessary.

What we are here concerned with, is the final result of such exercises of individual thought powers. In the case of the solitary forms, such new conceptions die with the individual. Though they may exert an influence on the development of the nervous system, and aid in the hereditary transmission of more active brain powers, they are lost as special ideas, fail to be taken up and repeated by other members of the species. This is not the case with the social animals. Each of these has some faculty of observation and some tendency to imitation, and useful steps of advance made by individuals are likely to be observed and retained as general habits of the community. Anything of importance that is gained may be preserved by educative influences. The facility of mental communication between these creatures is perhaps much greater than is generally supposed, and acts of importance which are not directly observed might in many cases be transmitted through repetition for the benefit of the group. We know this to be the main agency in human progress. New ideas are of rare occurrence with man. Ideas of permanent value do not occur to one per cent., perhaps not to one hundredth of one per cent., of civilized mankind, yet few of such ideas are lost, and that which has proved of advantage to an individual soon becomes the common possession of a community.

Among the lower animals new and advantageous ideas are probably of exceedingly rare occurrence. When they do occur, their advantage to solitary forms is very slight, being that of minute steps of brain development and hereditary transmission of the same. To social forms they are doubly advantageous, since, while they tend to brain development, they may also be preserved in their original form, and transmitted directly to members of the group. They are still more advantageous to the communal animals, from the closer intercourse of these, and their constant association in acts of mutual aid. But in the latter instance their influence is usually exerted for the benefit of the community as a unit, while in the case of social animals it is of advantage to the individual.

The result of such a process of evolution in the case of the communal animals is a strict specialism. A series of acts of advantage to the community are slowly developed, and are repeated so frequently that they become instinctive, while a fixed circle of duties arises, through whose links it is almost impossible to break. There is no reason to believe that the individual initiative is wanting. The varied round of duties of a community of ants, for instance, could only have arisen through step after step of progress from the condition of the solitary ants. If such steps have been made, others may be made, and are likely to be preserved if found advantageous. The ant individual preserves its powers of observation and thought and may initiate new processes. But most of the ant communities are already so excellently adapted to the conditions of their life as to leave little opportunity for improvement, so that the adoption of new and advantageous habits are certain to be exceedingly rare.

It is an interesting fact that communalism has been confined to animals of comparatively low organization. The most complete examples of it exist in the polyps and some other low forms, in which each community has become a compound individual, the members remaining attached to the parent stock. The next higher examples to be met are the frequently cited ants and bees, belonging to the lowly organized class of arthropoda, yet, through the advantage of association and mutual aid, developing actions and habits only found elsewhere in the human race. The only example among vertebrates is that of the beavers, members of the low order of rodents. With these the results are less varied and intricate than with the ants, in accordance with the much smaller size of the community. All the higher vertebrates are either social or solitary in habit, and among them the narrow specialism of the communal forms does not exist. Each individual works in large measure for itself, its mental powers remain generalized, and it is not tied down to the performance of a series of fixed hereditary acts from which escape is well-nigh impossible.

Of the social animals, man presents the most complete type, and the one from which we can best deduce the conditions of the class. A human community is made up of individuals of many degrees of intellectual ability, the mass remaining at a low level, the few attaining a high level. Yet those of high powers of intellect set the standard for the whole, teach the lower either by precept or example, and aid effectively in advancing the standard of the community. A rope or chain is said to be as weak as its weakest part. A human community, on the contrary, may be said to be as strong as its strongest part. The standing of the whole is dependent upon the thoughts and acts of the few, from whom the general mass receive new ideas and gain new habits. The existing intellectual and industrial position of mankind is very largely a result of ideas evolved by individuals age after age, and preserved as the mental property of the whole. Destroy the books and works of art and industry of any community, cut off its intellectual leaders, remove from the general mind the results of education, and it would at once fall back to a low level and be obliged to begin again its slow climb upward. The intellectual standing of any civilized nation depends upon two things: the preservation in books, in memory, and in works of art and industry, of the ideas of ancient workers and thinkers; and the mental activity of living thinkers and inventors, whose work takes its start from this standpoint of stored-up thought. Rob any community of all its basic ideas, and it would quickly retrograde to a primitive condition of thought and organization, from which it might need many centuries to emerge.

It has been said above that man is the highest example of the social animal. While that is the truth, it is not the whole truth. He is at the same time the highest example of the communal animal. Mutual aid, organization into strictly rounded communities, labor for the good of the whole, is as declared in him as in the most developed community of the ants, and we admire the work of the latter simply because they repeat at a lower level the work of man. In truth, in man we have a splendid example of the existence of the individual initiative in connection with the communal organization. Specialism exists in a hundred forms. Some nations have been tied down by it to conditions almost as fixed as those of the ants. But generalism exists in as full a measure, new ideas are constantly modifying or replacing the old, and the communism of man is a progressive one, steadily borne upward on the wings of new ideas. Individual thought has the fullest swing, and it is to the system of special reward for useful thought and act that man owes much of his great advance. On the other hand, reward without useful service has been one of the leading agencies that have acted to check human progress.

The lower animals do not possess the advantage of man in his power of preserving the thoughts and products of the past as a foundation for new steps of progress. Memory may aid them to a slight degree, but they have no special means of recording useful ideas. This cannot fairly be said of the communal forms, which possess the result of the labors of former generations as useful object lessons. But in the higher animals no means exist for the permanent preservation of ideas, and each step of progress must be due to the direct influence of living individuals and the indirect result of natural selection.

This is one cause of the slow mental advance of the lower animals. A second is the deficiency in educational influences, which have had so much to do with human progress. Education is not quite wanting in the brute creation. There are many instances on record of instruction given by the adults to the young. But this agency is in its embryo stage, and its influence must be small. Again, each tribe of lower animals is apt to fall into a fixed circle of life acts, to become so closely adapted to some situation or condition that any change of habits would be likely to prove detrimental. This is a state of affairs tending to produce stagnation and vigorously to check advance. Many instances of this could be cited from human history, while it is the common condition with the animals below man.

To return to the apes, the considerations above taken lead to the conclusion that it is chiefly, if not solely, to their social habits that they owe their mental quickness. While only in minor traits communal, they are eminently social, and have doubtless derived great advantage from this. The lemurs, which share their habitat and resemble them in organization, are markedly unsocial, and are as mentally dull as the apes are mentally quick. Possibly, the thought powers of the apes once set in train, there may have been something in the exigencies of arboreal life that quickened their powers of observation; but we are constrained to believe that the main influence to which they owe their development is that of social habits, in which they stand at a high, if not the highest, level among the distinctly social animals.

The thought capacities of the ape intellect are general, not special. The mind of these animals remains free and capable of new thought in new situations. It is fully alive to the needs and dangers of arboreal life, and advances no farther in its native habitat because there is nothing more of importance to be learned. But while fixed it is not stagnant. When the ape is taken from its native woods and put among the many new conditions arising on shipboard and in human habitations, we quickly perceive indications of its mental alertness. Its faculties of observation and imitation are actively exercised, and new habits and conceptions are quickly gained. Could the apes be made to breed freely in captivity, so that a domestic race, comparable to that of the dogs, could be obtained, their mental powers might, perhaps, be cultivated to an extraordinary degree, yielding instances of thought approaching that of man. The ape is especially notable for its tendency to attempt new acts of itself, not waiting to be taught, as in the case of other domesticated animals. In short, it seems by all odds to be the animal best fitted mentally to serve as the basis of a high intellectual development, as it is the best fitted physically to change from the attitude of the quadruped to that of the biped.

The anthropoid apes in general manifest a reversion from the social toward the solitary state, this condition reaching its ultimate in the orang, which is one of the most solitary of animals. The smaller forms are the most social, the gibbons being decidedly so. There is very good reason to believe that the man-ape was highly social, if we may judge from what we find in all races of men, and all grades, from the savage to the civilized. This animal was thus in a position to avail itself of all the advantages of the social habit, and to gain the mental development thence arising. How long ago it was when it left the trees and made its home upon the ground, it is impossible to say. It may have been as far back as the early Pliocene or the late Miocene Period, or even earlier. As yet its brain was probably no more developed than in the case of the other anthropoids, perhaps less so than in the existing species. But in its new habitat it was exposed to a series of novel conditions that must have exerted a healthful and stimulating influence upon its mind.

If it had remained in the trees we should probably to-day have only a man-ape still. Leaving their safe shelter for the ground, it became exposed to new dangers and was forced to fit itself to fresh conditions. Prowling carnivorous animals haunted its new place of residence, and these it had to avoid by speed or alertness of motion, or combat them by strength and the use of weapons. The carnivorous tastes which it had in all probability gained, made it a creature of the chase, pursuing swift animals, capturing them by fleetness or stratagem, or bringing them down with the aid of clubs and missiles. Such a new series of duties and dangers could not fail to exert a vigorous influence upon a brain already quick of thought and susceptible to fresh impressions, and we may well conceive that the man-ape then entered upon a new and rapid phase of mental progress, its brain developing in powers and growing in dimensions as it slowly became adapted to its new situation and grew able to cope with fresh demands and critical exigencies.

There is still another influence which has had its share, perhaps a very prominent share, in the intellectual development of animals, yet which no writer seems to have considered from this point of view. The probable effect of this influence needs to be taken into account, in conclusion of this section of our subject. It is that of the comparative agency of the senses in the development of the mind, and the effects likely to arise from the dominance of some one of the senses.

In the lowest animals touch was the predominant, if not the only sense, taste perhaps being associated with it. But these senses, which demand actual contact with objects, obviously could give none but the narrowest conception of the conditions of nature. The other senses, sight, hearing, and smell, give intimations of the existence and conditions of more or less distant objects, and their development greatly widened the scope of outreach in animals and must have exerted a powerful influence upon the growth of mental conditions.

It need scarcely be said that the sense which gives the fullest and most extended information about existing things is necessarily the one that acts most effectively upon the mind, and that this sense is that of sight. Hearing and smell yield us information concerning certain local conditions of objects, but sight extends to the limits of the universe, while in regard to near objects it has the advantage of being practically instantaneous in action and much fuller in the information it conveys. Sight, therefore, is evidently the most important of the senses, so far as the broadening of the mental powers is concerned, and any animal in which it is predominant must possess a great advantage in this respect over those species controlled to any great degree by one of the lower senses.

It may be said here that sight only slowly gained dominance in animal life. Though the eye, as an organ of vision, is found at a low level in the animate scale, the indications are that it long played a subordinate part, and has gained its full prominence only in man. During long ages life was confined to the sea, hosts of beings dwelling in the semi-obscurity of the under waters, and great numbers at too great a depth for light to reach them. To vast multitudes of these sight was partly or completely useless. The same may be said of hearing, the under-water habitat being nearly or completely a soundless one. The only one of the higher senses likely to be of general use to these oceanic forms is that of smell, and it may be that their knowledge of distant objects was mainly gained through sensitiveness to odors.

Of invertebrate land animals the same must be said. The land mollusks and the great order of insects and other land arthropods only to a minor extent dwell in the open light. Very many species haunt the semi-obscurity of trees or groves, hide among the grasses, lurk under bark, sticks, and stones, or dwell through most of their lives underground. Hosts of others are nocturnal. To only a small percentage of insects can sight be of any great utility, while hearing seems also to be of slight importance. Smell is probably the principal sense through which these animals gain information of distant objects.

There is existing evidence that the sense of smell in some insects is remarkably acute. The imprisoned female of certain nocturnal species, for instance, will attract the males from a comparatively immense distance, under conditions in which neither sight nor hearing could have been brought into play. The emission of odors and acute sensibility to them is the only presumable agency at work in those instances. As regards the most intelligent of the insects, the ants and the termites, the former are largely subterranean, the latter not only subterranean, but blind. In the one case, sight can play only a minor part, in the other, it plays no part at all. Touch and smell seem to be the dominant senses in these animals, and the degree of intelligence they display shows of how high a development these senses are susceptible. Yet the intelligence arising from them must necessarily be local and limited in its application; it cannot yield the breadth of information and degree of mental development possible under the dominance of sight.

In the vertebrates we find a fully developed and broadly capable organ of vision, and it might be hastily assumed that in those animals sight is the dominant sense. But there are numerous facts which lead to a different conclusion. Many of the vertebrates are nocturnal, many dwell in obscure situations, many in the total darkness of caverns, underground tunnels and excavations, or the ocean's depths. To all these sight must be of secondary importance. Hearing also can be of no superior value, and the dominant sense must be that of smell. In the bats there would appear to be a remarkably acute power of touch, if we may judge from the facility with which they can avoid obstacles at full flight after their eyes have been removed.

It might, however, be supposed that in the higher land vertebrates sight is predominant, and that the diurnal mammals depend principally upon their eyes for their knowledge of nature. But there are facts which throw doubt upon this supposition. These facts are of two kinds, external and internal. That the quadrupeds, in general, are highly sensitive to odors is well known, and also that they trust very largely to the sense of smell. Hunters are abundantly aware of this, and have to be quite as careful to avoid being smelt by their game as to avoid being seen. We have abundant evidence of the remarkable acuteness of this sense in so high an animal as the dog, which can follow its prey for miles by scent alone, and can distinguish the odors, not only of different species, but of different individuals, being capable of following the trail of one person amid the tracks of numerous others.

The internal evidence of this fact is equally significant. In the vertebrates, in general, the olfactory lobe of the brain is largely developed, much exceeding in size the lobe of the optic nerve. It forms the anterior portion of the cerebrum, and in many instances constitutes a large section of that organ, being marked off from it by only a slight surface depression. If we can fairly judge, then, by anatomical evidence, the sense of smell plays a very prominent part in the life of all the lower vertebrates. If we take our domestic animals as an example, the olfactory lobe of the horse is considerably larger than that of man, though the brain, as a whole, is very much smaller, so that, comparatively, this organ constitutes a much larger portion of the total brain. The other domestic animals yield similar evidence of the great activity of the sense of smell.

While there is no doubt that sight is an active sense in all the higher quadrupeds, it evidently divides this activity with smell to a much greater degree than is the case with man, in whom smell plays a minor part, sight a major part, among the organs of sense.

This fact shows its effect in the comparative mental development of man and the lower animals. Man, depending so largely on vision, gains the broadest conception of the conditions of nature, with a consequent great expansion of the intellect. The quadrupeds, depending to a considerable degree upon smell for their conceptions of nature, are much narrower in their range of information and lower in their mental development. As regards the ape family, it occupies a position between man and the quadrupeds, and its intellectual activity may well be due in great measure to an increased trust in sight and a decreased trust in smell in gaining its conception of nature.

The question may arise, Why, if sight has this superiority over smell, did it not long since gain predominance, and relegate smell to a minor position? It may be answered that the superiority of sight is not complete. In one particular this sense is inferior to smell. The leading agency in the development of the sense organs of animals has been the struggle for existence, including escape from enemies, and the perception of food-animals or material. In these processes acuteness of smell plays a very important part. It has, moreover, the advantage of gathering information from all directions, while sight is very limited in its range. The eye is so subject to injury that its multiplication over the body would be rather disadvantageous than otherwise, while, localized as it is, a movement of the head is necessary to any breadth of vision, and the whole body must rotate to bring the complete horizon under observation. It seems evident, from these considerations, that sight is much inferior to smell in the timely perception of many forms of danger. Light comes in straight lines only, and a movement of the body is necessary to perceive perils lying outside these lines. Odors, on the contrary, spread in all directions, and make themselves manifest from the rear as well as the front.

In all probability this fact has had much to do with the continued dependence of animals on smell. In fishes and reptiles a full sweep of vision is so slowly gained that some more active sentinel sense is requisite to safety. In mammals the head rotates more easily, but valuable time is lost in the rotation of the whole body. These animals, therefore, depend on both sight and smell, in some cases equally, in some more fully on one or the other of these senses. When we reach the semi-upright ape, we have to do with a form capable of turning the body and observing the whole surrounding circle of objects more quickly and readily than any quadruped. As a result, these animals have grown to depend more fully on vision and less on smell than the quadrupeds. Finally, in fully erect man, the power of quick turning and alert observation of the whole circle of the horizon reaches its ultimate, and in man sight has become in a large degree the dominant sense, and smell has fallen to a minor place.

With this change in the relations of the senses has come a change in the degree of mental development. It is highly probable that the dependence of the apes on vision instead of smell has had much to do with their mental activity, quickness of observation, and active curiosity. In man there can be no question that it has played a great part in the rapid development of his intellectual powers, and in the extraordinary breadth of his conception of nature as compared with that of the lower animals. While hearing and smell advise us of neighboring conditions only, and have their chief utility as aids to the preservation of existence, sight makes us aware of the conditions of nature in remote localities, extending far beyond the limits of the earth. While this sense plays its part as one of the protective agencies, it is still more useful as an agent in the acquisition of knowledge in general, and has much to do with the development of the intellectual faculties. We may look, therefore, upon the increasing dominance of the sense of sight as a leading agency in the making of man as a thinking being, and may ascribe to this in a considerable measure the thirst for information and faculty of imitation so marked in the apes.



VII

THE ORIGIN OF LANGUAGE

One of the characteristics of man, of which we spoke as among those to which his high development is due, is that of language. There is nothing that has had more to do with the mental progress of the human race than facility in the communication of thought, and in this vocal language is the principal agent and in the fullest measure is the instrument of the mind. Human speech has, in these modern times, become remarkably expressive, indicating all the conditions, relations, and qualities, not only of things, but of thoughts and ideal conceptions. And the utility of language has been enormously augmented by the development of the arts of writing and printing. Originally thought could only be communicated by word of mouth and transmitted by the aid of the memory. Now it can be recorded and kept indefinitely, so that no useful thought of able thinkers need be lost, but every valuable idea can be retained as an educative influence through unnumbered ages.

In this instrumentality, which has been of such extraordinary value to man, the lower animals are strikingly deficient. They are not quite devoid of vocal language, though it is doubtful if any of the sounds made by them have a much higher linguistic office than that of the interjection. But emotional sounds, to which these belong, are not destitute of value in conveying intelligence. They embrace cries of warning, appeals to affection, demands for help, calls for food supplies, threats, and other indications of passion, fear, or feeling. And the significance of these vocal sounds to animals may often be higher than we suppose. That is, they may not be limited to the vague character of the interjection, but may occasionally convey a specific meaning, indicative of some object or some action. In other words, they may advance from the interjection toward the noun or the verb, and approach in value the verbal root, a sound which embraces a complete proposition. Thus a cry of warning may be so modulated as to indicate to the hearer, "Beware, a lion is coming!" or to convey some other specific warning. We know that accent or tone plays a great part in Chinese speech, the most primitive of existing forms, a variation in tone quite changing the meaning of words. The same may be the case with the sounds uttered by animals to a much greater extent than we suppose.

We know this to be the case with some of the birds. The common fowl of our poultry yards has a variety of distinct calls, each understood by its mates, while special modulations of some call or cry are not uncommon among birds. The mammalia are not fluent in vocal powers, their range of tones being limited, yet they certainly convey definite information to one another. Recent observers have come to the conclusion that the apes do, to a certain extent, talk with one another. The experiments to prove this have not been very satisfactory, yet they seem to indicate that the woodland cries of the apes possess a certain range of definite meaning.

We are utterly ignorant of what powers of speech the man-ape possessed. It must, in its developed state as a land-dwelling, wandering, and hunting biped, have needed a wider range of utterance than during its arboreal residence. It was exposed to new dangers, new exigencies of life affected it, and its old cries very probably gained new meanings, or new cries were developed to meet new perils or conditions. In this way a few root words may have been gained, rising above the value of the interjection, and expressing some degree of definite meaning, though still at the bottom of the scale of language, the first stepping stones from the vague cry toward the significant word.

Between this stage and that of human language an immense gap supervenes, a broad abyss which it seems at first sight impossible to bridge. As the facts stand, however, it has been largely bridged by man himself. Side by side with the highly intricate languages which now exist, are various primitive forms of speech which take us far back toward the origin of human language. So advanced a people as the Chinese speak a language practically composed of root words, the higher forms of expression being attained by simple devices in the combination of these primitive word forms. The same may be said, in a measure, of ancient Egyptian speech. We can conceive of an early state of affairs in which these devices of word compounding were not yet employed, and in which each word existed as a separate expression, unmodified by association with any other word. Among the savage races of the earth very crude forms of language often exist, the methods of associating words into sentences being of the simplest character, though few surpass the Chinese in simplicity of system.

But all this represents an advanced stage of language evolution, a development of thought and its instrument which has taken thousands of years to complete. We cannot fairly judge from it what the speech of primitive man may have been, for in every case there has been a long process of development; aided, no doubt, in many cases, by educative influences acting from the more advanced upon the speech of the less advanced races.

If we seek to analyze any of these languages, the most intricate as well as the least advanced, we find ourselves in most instances able to isolate the root word as the basic element of speech. From this simple form all the more developed forms seem to have arisen. Take away their combining devices, and the root words fall apart like so many beads of speech, each with a defined significance of its own and fully capable of existing by itself. The Aryan and the Chinese especially offer themselves to this analytic method. Strip off the suffixes and affixes from Aryan words, get down to the germinal forms from which these words have grown, isolate these germs of speech, and we find ourselves in a language of root forms, each of which has grown vague and wide in significance as the modifying elements that limited its meaning have been removed. In the Chinese the problem is a much simpler one. We need simply to take the existing words out of their place in the sentence and let them stand alone, and we have root words at first hand. We may go through the whole range of human speech and, with more or less difficulty, arrive at a similar result. In short, the evidence seems conclusive that the language of mankind began in the use of isolated words of vague and broad significance, and that all the subsequent development of language consisted in the combination of these words, with a modification and limitation of their meaning, the families of speech differing principally in the method of combination devised.

It must, indeed, be said that in isolating the root forms of modern languages we reach conditions still far removed from those of primitive speech. These roots are in a measure packed with meaning. Time has added to their significance, and they lack the simplicity they probably once possessed. In particular, they have gained ideal senses, entered in a measure into that broad language of the mind which has been gradually added to the language of outer nature. The recognition of the existence of mind and thought doubtless came somewhat late in human development. Man long knew only his body and the world that surrounded it. Step by step only did he discover his mind. And when it became necessary to speak of mental conditions, no new language was invented, but old words were broadened to cover the new conditions. The mind is analogous to the body in its operations, ideas are analogues of things, and it was usually necessary only to add to the physical significance of words the corresponding ideal significance. In this way a secondary language slowly grew up, underlying and subtending the primary language, until the words invented to express the world of things were employed to include as vast a world of thoughts.

In getting down, then, to the language of primitive man we are obliged to divest the root forms of speech of all this ideal significance, and confine them to their physical meanings. In dealing with the languages of the least advanced existing tribes of mankind, indeed, little of this is requisite. The language of the mind with them has not yet begun its growth or is in its first simple stages. Only half the work of the evolution of language is completed. There is, indeed, no tribe so undeveloped as to use the primitive forms of speech. The most savage of the races of mankind have made some progress in the art of combining words, gained some ideas of syntax and grammatical forms. Yet in certain instances the progress has been very slight, and in all we can see the living traces of the earlier method of speech from which they emerged.

It is to the ability to think abstractly and to form words with an abstract significance that human language owes much of its high development. But this ability is largely confined to civilized mankind, savages being greatly or wholly lacking in it. This deficiency is indicated in their modes of speech. Thus a native of the Society Islands, while able to say "dog's tail," "sheep's tail," etc., has no separate word for tail. He cannot abstract the general term from its immediate relations. In the same way the uncivilized Malay has twenty different words to express striking with various objects, as with thick or thin wood, a club, the fist, the palm, etc., but he has no word for "striking" as an isolated thought. We find the same deficiency in the speech of the American Indians. A Cherokee, for instance, has no word for "washing," but can express the different kinds of washing by no less than thirteen distinct words.

All this indicates a primitive stage in the evolution of language, one in which every word had its immediate and local application, while in each word a whole story was told. The power of dividing thought into its separate elements was not yet possessed. As thought progressed men got from the idea of "dog" to that of "dog's tail." They could not think of the part without the whole. Then they reached a word for "dog's tail wags." But the idea of "wags" as an abstract motion was beyond their powers of thought. They could not think of action, but only of some object in action. The language of the American Indians was an immediate derivation from this mode of word formation, every proposition, however intricate it might be, constituting a single word, whose component parts could not be used separately. The mode of speech here indicated is one form of development of the root. Other forms are the compounding of the Chinese and the Mongolian and the inflection of the Aryan and the Semitic, all pointing directly back to the root form as their unit of growth.

The inference to be drawn from all this is that the language of primitive man consisted of isolated words, sounds which may originally have been mere cries or calls, but which gradually gained some definiteness of meaning, as signifying some of the varied conditions of the outer world. This is the conclusion to which philologists have now very generally come. The recognition that language consists of root words, variously modified and combined, leads back irresistibly to a period in which those roots had not yet begun to be modified and combined. The roots are the hard, persistent things in human speech. Grammatical expedients are the net in which these roots have been caught and confined. Free them from the net, and it falls to pieces, while the roots remain intact, the solid and persistent primitive germs of speech.

Yet in isolating root language as the basis of grammatical language we go far toward closing the gap between animal and human speech. It is still, doubtless, of considerable width, yet the distinction is no longer one of kind, but is simply one of degree. Primitive man had a much greater scope of language than is possessed by any of the lower animals, and the vocal sounds used had a clearer and more definite significance; but their nature was the same. They doubtless began in calls and cries like those in use by animals, and though these had increased in number and gained more distinct meanings, the difference in character was not great. In short, the analytic method employed by modern philologists has gone far to remove the supposed vast distinction between brute and human speech, and has traced back the language of man to a stage in which it is nearly related in character to the language of animals. The distinction has been brought down to one of degree, scarcely one of kind. A direct and simple process of evolution was alone needed to produce it, and through that evolution man undoubtedly passed in his progress upward from his ancestral stage.

The language of the lower animals is a vowel form of speech. It lacks the consonantal elements, the characteristic of articulation. In this man seems to have at first agreed with them. The infant begins its vocal utterances with simple cries; only at a later age does it begin to articulate. If we may judge from the development of language in the child, man began to speak with the use of sounds native to the vocal organs, and progressed by a process of imitation, endeavoring to reproduce the sounds heard around him: the voices of animals, the sounds of nature, etc. This tendency to imitate is not peculiar to man. It exists in many birds, and in some attains a marked development. The mocking bird, for instance, has an extraordinary flexibility of the vocal organs and power of imitating the voices of other birds. The parrot and some other birds go farther in this direction, being capable of using articulate language and clearly repeating words used by man.

None of the mammalia possess this facility. It is not found in the apes, and probably was not possessed by the ancestor of man. But it is not difficult to believe that in the efforts of the latter to gain a greater variety of vocal utterance, its organs of speech became more flexible, and in time it gained the power of articulation.

There are races of existing men whose powers of language seem still in the transition stage between articulate and inarticulate speech. This seems the case with the Bushmen and Hottentots of South Africa, whose vocal utterances consist largely of a series of peculiar clicks that are certainly not articulate speech, though on the road toward it. The Pygmies of the Central African forests seem similarly to occupy an intermediate position in the development of language. Those who have endeavored to talk with them speak of their utterance as being inarticulate in sound. It appears to be a sort of link between articulate and inarticulate speech. In short, the great abyss which was of old thought to lie between the languages of man and the lower animals has largely vanished through the labors of philologists, and we can trace stepping-stones over every portion of the wide gap. The language of man has not alone been evidently a product of evolution, but also one of development from the vocal utterances of the lower animals; and the man-ape, in its slow and long progress from brute into man, seems to have gradually developed that noble instrument of articulate speech which has had so much to do with subsequent human progress.



VIII

HOW THE CHASM WAS BRIDGED

In his bodily formation the man-ape differed little from man. The differences which existed were probably of a minor character, no greater than could readily exist within the limits of a species. If this assertion be questioned, it seems sufficient to call attention to the recent researches into the anatomy of the anthropoid apes, which differ in species, if not in genera, from man, yet are closely similar to him in all their main features of organization. Even in the brain, to whose great development man owes his superiority, the only marked difference is in size. Structurally, the distinctions are unimportant. If, then, these distant relatives so closely resemble man in physical frame, his immediate relative in the line of descent must have approached him still more closely in organization. After this ancestor had become a true, surface-dwelling biped, the differences in structure were probably so slight that physically the two forms were in effect identical. The man-ape was, as there is reason to believe, considerably smaller than man, perhaps about equal in size and stature to the chimpanzee, but that does not constitute a specific difference. There may have been some differences in the skeletal and muscular structure. The vocal organs, for instance, probably differed, the evolution of language in man being accompanied with certain changes in the larynx. The skull was certainly much more ape-like. Yet variations of this kind, due to differences in mode of life, are minor in importance, and may easily come within the limits of a species. While the great features of organization remain intact, small changes, due to new exigencies of life, may take place without affecting the zooelogical position of an animal. The most striking difference between man-ape and man, that of the development of the brain to two or three times its size and weight, is similarly unessential in classification while the brain remains unchanged in structure. That it has remained unchanged we may safely deduce from the close similarity between the brain of man and those of the existing anthropoid apes. The cause of the increase in size is so evident that it need only be referred to. Since the era of the man-ape, almost the whole sum of the forces of development have been centred in the mental powers of this animal, with the result that the brain has grown in size and functional capacity, while the remainder of the body has remained practically unchanged.

That man as an animal has descended from the lower life realm, none who are familiar with the facts of science now think of denying. This has attained to the scientist, and to many non-scientists, the level of a self-evident proposition. But that man as a thinking being has descended from the lower animals is a different matter, concerning which opinion is by no means in unison. Even among scientists some degree of difference of opinion exists, and such a radical evolutionist as Alfred Russell Wallace finds here a yawning gap in the line of descent, and is inclined to look upon the intellect of man as a direct gift from the realm of spirits. His explanation, it is true, is more difficult than the problem itself. There are no facts to sustain it, and even if he were not able to see how man's mind could be developed by natural selection, it is a sort of reductio ad absurdum to call in the angels to bridge the chasm.

Romanes has dealt with the subject from a different and more scientific point of view, and seems to have succeeded in showing that man's intellect at its lowest level is not different in kind from the brute intellect at its highest level. Controversy on this subject is too apt to be based on the difference between the intellect of the brute and that of enlightened man, in disregard of the great mental gap which exists between the latter and the thought powers of the lowest savage. In the preceding section an effort was made to show how crude and imperfect must have been the language of primitive man. Its imperfection was a fair gauge of that of his powers of thought. His intellect stood at a very low level, seemingly no further above that of the highest apes than it was below that of enlightened man.

In fact, enormous as is the interval between the mind of the brute and that of the man of modern civilization, the whole long line of mental development can be traced, with the exception of a comparatively small interval. This is the gap between the intellect of the anthropoid ape and that of primitive man, the one important last chapter in the story of mental evolution. Supernaturalism, driven from its strongholds of the past, has taken its last stand upon this broken link, claiming that here the line of descent fails, and that the gap could not have been filled without a direct inflow of intellect from the world of spirits or an immediate act of creation from the Deity.

This view of the case is not likely to be accepted as final. Science has bridged so many gaps in the kingdom of nature that it is not likely to retire baffled from this one, but will continue its investigations in place of accepting conclusions that have not the standing even of hypothesis, since they are unsupported by a single known fact. At first sight, indeed, the facts which bear upon this question seem stubborn things to explain by the evolution theory. The gap in intellect between the highest apes and the lowest man is a considerable one, which no existing ape seems likely ever to cross. However the anthropoid apes gained their degree of mental ability, it does not appear to be on the increase. They are in a state of mental stagnation and may have remained so for millions of years. Something similar, indeed, can be said of the lowest savages. They also are mentally stagnant. The indications are that for thousands, or tens of thousands, of years in the past their intellectual progress has been almost nothing. Yet it is beyond reasonable question that the advanced thinker of to-day has evolved from an ancestor as low in the mental scale as this savage, probably much lower; and this renders it very conceivable that a similar process of evolution covered the interval between the ape intellect and that of primitive man.

Somewhere, at some time in the far past, the mental stagnation of man was broken, and the development of the mind began its long progression toward enlightenment. This was not in the localities in which the lower savages are now found, the equatorial forests of Africa and South America and other realms of savage life, the change in all probability taking place elsewhere, under new and severe exigencies of life. Similarly we have much justification in saying that somewhere, at some time, the mental stagnation of the ape was broken, and the long development of the mind from ape to man began. This did not take place in the instances of the existing anthropoids, and, as in the analogous case of civilized man, its influencing cause must be looked for in exigencies of existence acting upon some form different in character and habitat from these apes.

The existing anthropoid apes may justly be compared in condition with the existing low savages. In both cases a satisfactory adaptation to their situation has been gained. These apes are still arboreal and frugivorous, as their remote ancestors were. They have for ages been in a state of close adaptation to their life conditions, and the influences of development have been largely wanting. Such evolution as took place must have been extremely slow. In like manner the lowest savages live in intimate relations with the conditions surrounding them. All problems of food-getting, habitation, climate, etc., have long since been solved, and in the tropical forests in which so many of them dwell they are in thorough accord with the situation. Mentally, therefore, they are practically at a standstill and have remained so for thousands of years. The two cases are parallel ones. We can safely say that the later development of man took place in other situations and under other conditions. We may fairly say the same in regard to the ape. Vigorous influences must have been brought to bear upon the ancestor of man as the instigating causes of its mental development into man; and similarly vigorous influences must have been brought to bear upon primitive man to set in train his mental development into intellectual man. And the general character of these influences in both cases may readily be pointed out. An extraordinary development has taken place in the human intellect within a few thousands, or tens of thousands, of years, yielding the difference which exists between the cultivated man of to-day and the debased savage who probably preceded him, and whose counterpart still exists. This has undoubtedly been due to influences of the highest potency. If we can show that influences of equal potency acted upon man's ancestor, we shall have done much toward indicating how the ape brain may have grown into the brain of man.

In both cases the main agency was in all probability that of conflict. Both ape and man, as we take it, developed through some form of warfare. In the former case it was warfare with the animal kingdom; in the latter it was warfare with the conditions of nature and with hostile man. Each of these has been potent in its effects, and to each we owe the completion of a great stage in the evolution of man.

In the tropics, the home of the anthropoid apes of to-day and, probably, of the animal we have named the man-ape, war between man and nature scarcely exists. Nature is not hostile to man. There is no occasion for clothing and little for habitation. Food is abundant for the sparse populations. Little exertion is called for to sustain life. Mental stagnation is very likely to supervene. Yet there, as elsewhere, conflict has had much to do with such mental progress as exists. Mastery in warfare is due to superior mental resources, which gradually arise from the exigencies of conflict, and manifest themselves in greater shrewdness or cunning, superior ability in leadership, better organization, fuller mutual aid, and the invention of more destructive weapons and more efficient tools. War acts vigorously on men's minds, peace acts sluggishly. In the former case man's most valued possession, his life, is in jeopardy, and his utmost powers are exerted for its preservation. Every resource within his power is brought to bear to save himself from wounds or death and to destroy his enemies. If the foes are equal physically, victory is apt to come to those which are superior mentally, which are quicker at devising new expedients, more alert in providing against danger, more skilful in the use of weapons, abler in combining their forces to act in unison. In short, the whole story of mankind tells us that mental evolution has been greatly aided by the influences of warfare, the reaction upon the mind of the effort at self-preservation, the destruction of those at a lower level of intellectual alertness, the preservation of the abler and more energetic, the effect of conflict in bringing into activity all the resources of the intellect, and the hereditary transmission of the powers of mind thus developed. It is, undoubtedly, to war between man and man, and the conflict with the adverse conditions of nature in the colder regions of the earth, that man's development from his lowest to his highest intellectual state has been largely due. This is by no means to say that war is still necessary for this result. Other influences are now at work, of equal or superior potency, and while the conflict with nature and the conditions of society is still of importance, war between man and man is no longer necessary as a mental stimulant. The time was, and that not very far in the past, when it was an essential element in human development.

If we descend to the lowest existing savages, however, it is to find this agency almost non-existent. We can perceive in them no organized warfare and no alert conflict with nature. They are as yet at the very beginning of this stage of evolution, and it certainly exerts little influence upon them. Nature is not adverse, life needs little thought or exertion, they accept the world as they find it, without question or revolt, and their thoughts and habits are as unchangeable as the laws of the Medes and Persians. But the fact that active warfare does not now exist among the lowest tribes of mankind, does not argue that such a state has never existed. In truth, we maintain that primitive man is the outcome of an active and long-continued warfare, and that his settled and sluggish condition to-day is the ease that follows victory. He has conquered and is at rest after his labors.

For if we compare primitive man with the anthropoid apes, it is to find one striking and important difference between them. The anthropoids are at a level in position with their animal neighbors. Man is lord and master of the animal kingdom, the dominant being in the world of life. He has no rival in this lordship, but stands alone in his relation to the animal kingdom. He is feared and avoided by the largest and strongest beasts of field and forest. He does not fight defensively, but offensively, and whatever his relation to his fellow-man, he admits no equal in the world of life below him. He is the only animal that has made a struggle for lordship. The gorilla is said to attack the lion and drive it from its haunts. If it does so, it is not with any desire for mastery, but simply to rid itself of a dangerous neighbor. The battle for dominion has been confined to man, and in the winning of it no small degree of mental development must have taken place.

The supremacy of man was not gained without a struggle, and that a severe and protracted one. The animal kingdom did not yield readily to man's lordship, and the war must have been long and bitter, settled as the relations now seem. Rest has succeeded victory. The lower animals are now submissive to man, or retire before him in dread of his strength and resources, and the strain upon his powers has ceased. So far as this phase of evolution is concerned the influences aiding the mental development of man have lost their strength. The warfare is over, and man reigns supreme over the kingdom of life.

Of all animals the man-ape was the best adapted for such a struggle. The other anthropoid apes, while favored by the formation of their hands, lacked that freedom of the arms to which man mainly owes his success. No other animal has ever appeared with arms freed from duty in locomotion and at the same time endued with the power of grasping, and these are the features of organization to which the evolution of the human intellect was wholly due in its first stages. The man-ape was not able to contend successfully with the larger animals by aid of its natural weapons. Its diminutive size, its lack of tearing claws, and its lesser powers of speed, left it at a disadvantage, and had it attempted to conquer by the aid of its strength and the seizing and rending powers of teeth and nails, its victory over the larger animals would never have been won. Even with the aid of the cunning and alertness of the apes, their power of observation, their combination for defence and attack, and their general mental superiority to the tenants of the animal world, their supremacy in the event of their becoming carnivorous must have been confined to the smaller creatures, and could not have been established over the larger animals of their native habitat except through the aid of other than their natural powers.

It was by the use of artificial weapons that the conquest was gained. The tendency to use missiles as weapons of offence and defence, which is shown by various species of monkeys, was in all probability greatly developed by the man-ape, the only carnivorous member, if our premises are correct, of the whole extensive family of the apes, and the only one with the free use of its hands and arms. By the use of weapons of this kind the powers of offence of this animal were enormously increased. As skill was acquired in their use, and more efficient weapons were selected or formed, the man-ape steadily advanced in controlling influence, and the lower animal world became more and more subordinated. No doubt the struggle was a protracted one. The previously dominant animals did not submit without a severe and long-continued contest. Thousands of years may have passed before the larger animals were subdued, for it is probable that the invention of superior weapons by an animal of low mental powers was a very slow process. Each stage of invention gave higher success, but these stages were very deliberate ones.

However this be, we can be assured that the superiority of the ancestral man lay in his mental resources, and that his victory was due to the employment of his mind rather than of his body. As a result, the developing influence of the conflict was exerted upon his brain, the organ of the mind, far more than upon his physical frame, and this organ gradually increased in size, while the body as a whole remained practically unchanged. The conflict began with the man-ape on a level in power and dominance with animals of its own size and inferior to those of greater size and strength. It ended with man dominant over all the lower animals. Such a progress, if made by any animal through variation in physical structure, must have caused radical and extraordinary changes in size, strength, and utility of the natural organs of offence. If made, as in the instance in question, through development of the organ of the mind alone, it could not but have produced a great increase in the size and power of this organ; and the dimensions of the brain in primitive man, as compared with those of the brain in the anthropoid apes, do not seem too great for the magnitude of the result.

The conflict ended, a new animal, man, finally and fully emerged from the family of the apes and settled down in the restful consciousness of victory, with a much larger brain and greatly superior mental powers than were possessed at the beginning of the struggle, yet in physical aspect not greatly changed from his ancestral form after it had first fully gained the erect attitude. The powers gained enabled early man easily to hold the position he had won, and there was no further special strain upon his faculties until a new contest began, that between man and nature, supplemented by a still more vital struggle, that between man and man.

To return to the point from which we set out, it may be said that, as the man-ape gained facility in walking in the erect attitude, and its hands and arms became fully adapted to the use of weapons, its standing in the animal kingdom changed essentially from that before held. Fear and flight ended, retreat ceased, attack began, pursuit succeeded flight, and the great battle for mastery entered upon its long course. An element which aided materially in the victory was the social habit of the animal in question, and the mutual aid which the members of any group gave one another. Educative influences also naturally follow association, every invention or improvement devised by one becomes the property of the whole, and nothing of importance once gained is lost.

The stages of this progress were, undoubtedly, in their outer aspect, stages of improvement in weapons. We seem to see ancestral man, in his early career as a carnivorous animal, seizing the stones and sticks that came readily to hand, and flinging them with some little skill at his prey, in the same manner as we can perceive the baboon doing the same thing. In like manner we observe him breaking off branches from the trees and using them as clubs. One of the first steps of development from this crude stage in the use of weapons would be the selection of stones suited by size and shape for throwing, and the choice of clubs of suitable length and thickness, the latter being stripped of their twigs.

For a long time fresh weapons, those immediately at hand, would be seized and used for every new conflict; but as the idea of the superiority of some weapons to others arose, a second stage of evolution must have begun. The selected club, broken from the tree and prepared for use with some care, and thus embodying a degree of choice and labor, would be too valuable to fling idly away, and might be retained for future use, the first personal possession of inchoate man. Similarly, stones carefully chosen for their suitability for throwing would be probably kept, and a small store of them collected. In short, we may conceive of the man-ape thus gathering a magazine of weapons,—clubs and stones,—sought or shaped during hours of leisure for use in hours of conflict. In this way our animal ancestor doubtless slowly became a skilful hunter, carrying his weapons with him in the chase, and using them efficiently in the conquest of prey.

A third stage in this progress was reached when to some wise-headed old man-ape came the idea of combining the two forms of weapon in use, of fastening in some way the stone to the club in order that a more effective blow might be struck. The vegetable kingdom furnishes natural cords, flat stones with more or less cutting edges could be chosen and bound to the end of the club, and the earliest form of the battle-axe would be produced. With its formation the man-ape made another important step of progress and added greatly to his powers of offence. Stage by stage he was bringing his animal competitors under his control.

The formation of an axe or hatchet, however crude it may have been, would naturally lead to another step in advance. With it the ancestral man had passed beyond the possession of a weapon into the possession of a tool. The shaping of his clubs previously had been done by a rude tearing or hammering off of their twigs. These could now be cut off, and in addition the club might be wrought into a better shape. Manufacture had begun. Our ancestor stood at one end of a long line, at the other end of which we behold the steam-engine, the electric motor, and an interminable variety of other instruments.

Primitive manufacture was not confined to the shaping of wood. The shaping of stone followed in due time. If a tree branch could be made more suitable for its purpose by cutting it into shape with a rude stone axe or hatchet, a stone of better shape might be obtained by hammering. Doubtless the chipping effect of striking stone upon stone had been often observed before the idea arose that this could be made useful, and that where stones of the desired shape were not to be found, the shape of those at hand might in this way be improved.

If we seek for some turning-point, some stage of progress, in which the man-ape fairly emerged into man, perhaps it would be well to select that which we have now reached, that in which the animal in question, which had hitherto used the objects of nature in their natural form, first gained the idea of manufacture and began to shape these objects by the use of tools. In truth, the dividing line between man-ape and man was imperceptibly fine. Various points of demarcation might be chosen, each founded on some important step in evolution. But among them all that in which the effort to convert the objects of nature into better weapons by the use of tools is perhaps the best, as it was probably the first step in that long process of manufacture to which man owes his wonderful advance.

With this early effort at manufacture, man had reached a stage in which he was first able to make a permanent record of his existence upon the earth—aside from that of the very infrequent preservation of his bones as fossil remains. A chipped stone is a permanent object. Even a very rudely shaped one bears some indications of its origin upon its surface, some marks pointing back to man in his early days. Unfortunately for anthropologists, natural agencies sometimes produce effects resembling those achieved by man's hands, and some degree of skill in manufacture and well-marked design is necessary before one can be sure that a seeming stone weapon has not been shaped by nature instead of man. Within a recent period research for the evidence of early man in the shape of chipped stones has been diligently made, with an abundance of undoubted and a number of doubtful results. Some of these reach very far back in time, and if actually the work of man he must have lived upon the earth as a manufacturing animal for years that may be numbered by the million. Seemingly chipped stones have been found that belong to the remote Miocene geological age. With the latter are some scratches upon bones that also seem the work of tools. But these Miocene relics are questionable. They do not seem to surpass the shaping power of nature herself. Unless some more indubitable relics are found, we must place the advent of man as a tool-using animal at a much later date. How far back he may have existed as a man-like biped is another question, which we are not likely soon to solve.

It is scarcely necessary to pursue this branch of our subject farther. We have reached one end of a line of development, the succeeding course of which is well known. From the earliest rudely chipped stones and flints that are certainly the work of man, we can easily trace his progress upward through better examples of the chipped and later through those of the polished stone implement, until the age of metal began. And with these stones have been found many other indications of the progressing powers of man, in the shaping of bone, the invention and use of a considerable variety of implements and ornaments, and the earliest efforts of art, as stated in a preceding section. There is no occasion to go into the detail of these steps of progress. When they are reached, this section of our work ends. We are concerned here simply with man's ancestor and man in his earliest stage of existence, not with man in his later course of development.



IX

THE FIRST STAGE OF HUMAN EVOLUTION

The question has often been asked, if man has descended from an ape ancestor why is it that no traces of this ancestral form have been found in a fossil state? If man has gone through such an extended course of development, why has he left no remains? This question, looked upon as unanswerable by many of those who ask it, is really of minor importance. A half-dozen answers, each of considerable weight, could easily be made to it. In the first place, it may be said that the absence of remains referred to is far from a single instance, but one out of thousands. It is generally admitted that the species of animals found fossil are very far from representing all the species that have existed upon the earth, and probably form but a minute percentage of them. In the second place, the remains of man's ancestor have not been sought for in its native locality, the tropical regions. In the third place, man belongs to the class of animals least likely to be preserved in the fossil state, since they dwell in the depths of forests and at a distance from the lakes and streams in whose muddy bottoms the remains of so many animals have been fossilized. Another answer is, that of the various species of anthropoid apes that probably existed in the past, a few relics only of a single species have been found. If there were this one species alone, its number of individuals must have reached into the millions, yet of those hosts only a few fugitive bones are known to exist. There could not well be a more striking instance of the imperfection of the geological record. The sparse remains of Dryopithecus, the species in question, with some few other fossils of doubtfully anthropoid species, save us from a total blank, and open the vista to a myriad of active arboreal creatures which had their dwelling-place in the old-time European forests, but have almost utterly vanished from human knowledge.