Man And His Ancestor Part 7

It has been a frequently debated question whether man comprises a single species or two or more species of animal descent. If a line be drawn from the Gold Coast in tropical Africa to the steppes of Tartary in central Asia, it will present two markedly distinct races of men at its two extremities. At its southwestern end we find the most long-headed, prognathous, frizzly-haired, dark-skinned race of mankind. At its northeastern end is the most round-headed, orthognathous, straight-haired, and yellow-skinned race. Midway between these appear intermediate peoples, with heads round, oval, or oblong, hair straight or curly, skin fair or dark, faces upright or protruding, men possibly, to judge from their physical character, a result of the amalgamation of these two distinct races.

These differences may be the result of original difference in species or may be due to climatic and other influences of nature. Some writers accept the one view, some the other, and neither is sustained by any great weight of facts. The Pygmy race presents somewhat similar differences. Usually round-headed, these small men are in some instances long-headed, while such marked distinctions appear at times that Stanley cla.s.sed two neighboring tribes as separate races. Here they present features of the Mongolian, there they are similar to the Negro.

This goes to indicate that the distinction between the Negro and the Mongolian began far back in time, but it does not prove that it is the result of original difference in species, or that two distinct forms of ape separately developed into man. While this is quite possible, the theory of a single species has been most widely accepted. The chief writers on the subject think that the differences arose during that undeveloped stage of mankind when resistance to the transforming influences of nature was still weak, and when the structure of the human frame may have yielded readily to agencies which would have little or no effect upon it now.

Of one thing we can be sure, which is that there was a wide migration of the apes in remote times. Leaving the tropics, many species spread to the north, extending into Europe, which at that time seems to have been connected by land bridges with Africa, and spreading far through Asia.

There was probably nothing at that time in atmospheric conditions to check such a migration. The Tertiary climate of Europe is believed to have been quite mild. And the ape family is by no means necessarily confined to warm regions. Monkeys are found to-day at high elevations on the mountains of India, enduring the chill of ten thousand feet of alt.i.tude.

Of the migration to Europe abundant evidence exists, fossil remains of monkeys having been found in many localities of that continent. Among these residents of early Europe was at least one representative of the anthropoid apes, the fossil species known as Dryopithecus, from the middle Miocene deposits of St. Gaudens, France. This species, apparently most nearly allied to the chimpanzee, was taller than any existing ape.

Two or three other fossil remains, possibly of anthropoid apes of smaller size, have been found, and Europe seems to have been well supplied with apes of a considerable degree of development at a remote geological period. Among those may have been the form we have designated the man-ape, the ancestor of the human race, though no fossil relic attributable to such a species has been recognized.

Coming down to a much lower period, we begin to find traces of man, first in his rudely chipped and later in his polished stone weapons and tools. And the bones of man himself appear, extending through what is known as the Quaternary or Pleistocene period. Nearly all these remains have been preserved by the art of burial, a fact indicating some degree of mental progress, though their residence in caves and the rudeness of their implements are evidence that the race was still low in culture.

An interesting fact in connection with these ancient human remains is that most of them indicate a small race, with narrow skulls and prognathous jaws, recalling the Pygmies in general structure. This rude and small race continued until a late period of prehistoric time. It extended down from the cave bear and mammoth period through the later reindeer period, as is proved by discoveries made in the caves of the Belgian province of Namur. And there is good reason to believe that it continued into the age of bronze, for the small size of the handles of bronze weapons show they must have been intended for men with small hands.

These diminutive people seem to have been not over four feet eight inches high. They were not alone, however. Men of normal height were in Europe with them. The northward migration of the Pygmies seems to have been accompanied or followed by that of a full grown people. Yet the Pygmies have held their own in Europe as in Africa, with certain modifications. In Sicily and Sardinia, which form part of a supposed former land bridge between Africa and Europe, a small people about five feet high still exist, whom Dr. Kollman looks upon as representing a distinct race, the predecessors of the tall Europeans. In the Lapps of northern Europe we possess another small race, possibly the lineal descendents of the Quaternary Pygmies. Everywhere the small man has been forced to retire into forests, deserts, and icy barrens before the taller and stronger man. The folk-lore of Europe is full of traditions of a race of dwarfs, and its conflict with men of larger mould, and there are various indications that this race was once widespread.

What has been said here of the migration of man into Europe and his development in that country is preliminary to a consideration of the second great stage of human development, that due to the conflict with nature. The conflict with the animal world appears to have ended in the production of a dwarfish, forest-dwelling variety of man, in the lowest human stage of mental evolution. The conflict with nature ended in the development of a full-sized variety of man, dwelling largely in the open country and much superior in intellect, as indicated by his higher powers of thought and advanced degree of organization.

The conflict with nature took several forms, in accordance with the conditions of the several regions inhabited by man. Its result was to subdue nature to the use and benefit of mankind, and the methods, in the tropical localities of original man, consisted in the reduction of animals to the domestic state and a similar domestication of food plants. In other words, one of its early stages was the development of the herding habit, while a far more important one was that of the appearance of the agricultural industries. In Europe a third and still more vigorous influence supervened, that of the conflict with cold and man's gradual adaptation to the conditions of a frigid climate.

If the nomad dwarfs were the aboriginal men, all later races must have developed from them. While remaining in the forest and retaining their primitive habits, the Pygmies presented an instance of arrested evolution. For a new development to begin it was necessary to abandon the old locality and with it the old habits, and this they probably began to do at a remote period. When, indeed, the earth was their dominion, there was no reason for their remaining restricted to a forest residence, as they have been since the larger races took possession of the open country. We do not need to go back far in time in the East to find the Pygmy race in full control of the Philippine and other islands, and probably of Malacca and parts of Hindostan. Their present restriction and partial extermination have been due to the incursions of the warlike Malays. The Andaman Mincopies remained undisturbed until a recent date, and added fis.h.i.+ng to their hunting pursuits. And the canoes which these islanders now possess were probably the invention of their race, and furnished the means by which the aborigines spread from island to island of those thickly studded seas.

In Africa the only existing indication of a migration of the forest folk into the open country is found in the Bushmen and Hottentots of the far south. The former, confined to the desert, remain nomad hunters and present no step of advance beyond the Akka and other equatorial tribes.

The Hottentots, on the contrary, have made an important step of progress. While still nomads and addicted to hunting, they have domesticated cattle and sheep and become essentially a herding people, though mentally the lowest race of herders on the face of the earth.

With this change in habits, the Hottentots have significantly increased in stature. While still of medium height, they are considerably larger than their Bushmen kindred, to whom they present a close resemblance in other respects. This increase in size is a common result of a change in habits which insures a fuller supply of food with less strain upon the muscular organization in obtaining it; a fact of which the lower animal world is full of ill.u.s.trations. The life of the forest and desert hunters is one of incessant activity, and their food supply is precarious. The Hottentots, on the contrary, take life easily and are inclined to indolence, their herds supplying them with food in abundance with little exertion. They retain enough of the primeval strain to be fond of hunting, and while thus engaged display the activity of their ancestral race, but ordinarily they pursue an idle, wandering life, and their increase in size may well be a result of their change in habits.

The Hottentots, while still low in the human scale, are mentally a stage in advance of the Bushmen, they having a more developed social organization and superior powers of thought. The latter is indicated by their myths and legends, of which they have a considerable store, though they are in great measure dest.i.tute of religious conceptions, such religion as they possess taking in great part the primitive form of ancestor wors.h.i.+p. Under the influence of Europeans they are gradually abandoning their old habits and adopting those of civilized life, but while improving in social and industrial conditions there is little evidence of intellectual advance.

The development in method of food-getting displayed by the Hottentots was really but the completion of the old battle for dominion with the animal host. It consisted in subjecting some of the docile herbivora more fully to human masters.h.i.+p. The hunter has to do with hostile beasts, victims but not servants of man. The herder has reduced some of these animals to servitude, and no longer has to overcome them through the arduous labors of the chase. He is able to obtain, as we have said, more food with less exertion, a larger population can live in a limited district, and the beneficial effects upon the mind of a closer social intercourse are shown.

But the most important event in this stage of evolution was the subjection of the plant world to man. For ages of interminable length this was not thought of. Fruits and other vegetable products formed part of man's food; but these were the growth of wild nature, and the plant world was left to its own will, with no effort to bring it under human control. There is nothing to show that the idea of agriculture ever entered the mind of a Pygmy. Of the plants surrounding him, far the greater number were useless for food, only the few were available; but the conception of favoring the few at the expense of the many apparently never occurred to him. There is, indeed, some crude and simple agriculture pursued by a few of the Negritos of Luzon, but evidently as an imitation of the Malay agriculture or as a result of direct teaching, certainly not as an original conception. The conflict of the Pygmies with nature has been confined to the animal world, and reached its highest level in the herding industries of the Hottentots.

Where and when the subjugation of the plant world began it is impossible to say. It very probably had its origin in the fertile open lands of the tropics. But that it originated in the central region of Africa, or that the agriculturists of that region were of native origin, are both subjects open to question. The forest folk may have spread into the open country, there developed a crude agriculture, favored the growth of food plants at the expense of useless shrubs and trees, and gradually advanced in this new form of industry. This would be in accordance with the opinion of Virchow, who looks upon the negro as the descendant of the Pygmy. No great change was necessary to convert the one into the other. The Pygmy is negro-like in cast of countenance and bodily formation. He differs in size, in complexion, and in shape of head. But new conditions may have given rise to these differences. The fierce suns of the African lowlands may well have caused an increased deposit of pigment, changing the yellowish hue of the Pygmy to the deep black of the negro. An increase in size is a natural result when exertion diminishes and food increases. And a tendency for the head to change from the short to the long shape is shown in the Bushmen.

On the other hand, certain anthropologists, of whom we may name Quatref.a.ges, take an opposite view, and believe that the negroes migrated from Asia or the Eastern islands to Africa, being, like the negro-like Papuans, descendants of the sable or dark brown Negritos of the East. In this case agriculture may have originated in Asia and have been brought by migrants to Africa. All we know historically concerning it is that the earliest traceable seats of agriculture appear to have been the fertile valleys of India, Babylonia, and Egypt. But the known culture of the earth in these regions goes back only a few thousands of years, while for the first crude stages of agriculture we must probably measure years by tens of thousands.

The degree of subjection of nature to man's needs, as displayed in tropical agriculture, was comparatively small, and its effect on the development of the human intellect, while important, was limited. It had the highly useful result of a great increase in population, the growth of village and town life, an advance in social relations, and the beginning of political relations. New implements were needed, better houses were erected, the settled condition of the people gave rise to direct efforts at education, and added the important element of commerce, in its earliest form, to the industries of mankind. The result must have been a fresh start in the development of the intellect, though one that probably soon reached its culminating point in the central tropics.

The highest results of the development of agriculture in tropical countries, unaided by secondary influences, seem to have been those existing in the highly fertile regions of Egypt and Babylonia at the opening of the historical period. The density of population in those countries, due to their prolific production of food stuffs, gave rise to considerably developed political and social inst.i.tutions, and laid the foundations for a great subsequent advance under the influence of warfare, invasion, and the other more potent causes of human progress.

Only for such ulterior influences the agriculturists of these countries would perhaps to-day remain dormant in the stage of mental progress they had attained ten thousand years ago.

In considering the existing conditions of the forest nomads and the African agriculturists, it is not safe to credit them with the origination of all the arts and implements they possess. The negroes, for instance, have been for ages in more or less close a.s.sociation with the Pygmies, and may have taught them many things which they would not have attained through their own limited powers of thought. The bow and poisoned arrow are very likely original with them. They possess this weapon throughout the wide range from the African Hottentots to the Philippine Negritos, while it is not a weapon of the surrounding peoples. The spear is probably also original. The same cannot safely be said of their traps and snares for game. These seem beyond their power of invention, and may well have been taught them by the negro tribes.

Their habitations, aside from the mere leaf shelters, had probably a similar origin. In Africa the huts doubtless had their model in those of the negroes. In the Philippines they are pile-supported bamboo huts of the pattern of those of the Malays. If, then, we take from the forest folk the arts taught them or imitated by them, we reduce them to a very low level of intellect and a remarkable paucity of products from their own powers of thought.

Similar reasoning may be applied to the settled natives of Africa. For thousands of years past they have been in contact on their northern borders with civilized peoples, numerous immigrants have made their way into the country, and a considerable degree of amalgamation has very likely taken place. We cannot, therefore, safely credit them with all the arts and implements they possess nor with all their political and social progress. No doubt much came to them from without, much was taught them from within, and a mixture of blood with superior races may have aided considerably in improving their stock. We are justified, then, in their case as in that of the Pygmies, in believing that their stage of mental and social development is only in part original with them, and is largely due to the influences of education and amalgamation.

The pure negro is not a very numerous element of the population of Africa. He stands in a measure intermediate between the nomad Pygmies of the forest and the desert, and the mixed races who may be called negroid but cannot strictly be called negro. With their foreign blood, most of these have obtained foreign arts and elements of culture, and stand at a distinctly higher physical and mental level than the unamalgamated negro.

For the pure or nearly pure negro we must seek the lowlands of the Guinea coast, the seat of the most p.r.o.nounced existing negro type. Other localities are in the region of the Gaboon, along the lower Zambesi, and in the Benue and Shari basins. Here we find the true native African, a race strikingly uniform in aspect, and, next to the Pygmies, the lowest in physical characteristics of mankind. The features of structure in which the negro appears to occupy a position intermediate between the white man and the man-ape--lower than the former and approaching the latter--are the following: First, his abnormal length of arm, which averages about two inches longer than that of the Caucasian, and, when in the erect position, sometimes reaches the knee-pan, being little shorter proportionately than that of the chimpanzee. Second, his prognathism, or projection of the jaws--his index of facial angle being about 70, as compared with the Caucasian 82. Third, his weight of brain--average European 45 ounces, negro 35, highest gorilla 20. Fourth, his short, flat, snub nose, deeply depressed at the base, wide and with dilated nostrils at the extremity. Fifth, his thick protruding lips.

Sixth, his high and prominent cheek bones. Seventh, his great thickness of cranium, which resists blows that would break the skull of an average European. Eighth, the weakness of his lower limbs, the broad, flat foot and low instep, the projecting heel and somewhat prehensile great toe.

These characteristics the negroes possess in common with the Pygmies and the Negritos. Others of less significance could be named. One important character is that of the cranial sutures, which close much earlier in the negro than in higher races, thus checking the development of the brain while the body is still growing. To this many ascribe the mental inferiority of the negro race. A close observer records, as a result of long observation on the plantations of the southern United States, that "the negro children were sharp, intelligent, and full of vivacity, but on approaching the adult period a gradual change set in. The intellect seemed to become clouded, animation giving place to a sort of lethargy, briskness yielding to indolence." This is very probably the case with the Pygmies, who similarly reach a mental limit beyond which they cannot advance; but this limit is set in the adult period. In other words, the adult Pygmy is on the mental level of the negro child. If the African Pygmy is as short lived as his Eastern congener, he does not survive, as a rule, many years beyond the age of adolescence, and continues in a stage of childhood, mentally considered, until death.

The conclusion to be derived from this interesting fact would appear to be that the negro has made a distinct and important advance mentally beyond the Pygmy, reaching at adolescence the limit of mental evolution which the Pygmy reaches at death. But the negro stops here, or goes little beyond this limit. His cranial sutures close, the growth of the brain is arrested, and the development of his mind comes to an end. In the white the brain continues to expand, and the closing of the sutures takes place later in life. Probably the latter is a result of the former, mental development having overcome the tendency of the sutures to close in early life. It may be further said of the negro that, mentally, he is emotional far more than intellectual, and unmoral rather than immoral, he being apparently incapable of comprehending the moral conceptions of advanced man.

If we seek the Malaysian and Australasian region of the Eastern seas, we find there another branch of the negro race, similarly in contact with, and apparently derived from, a Pygmy stock. This Papuan race of blacks covers a wide island region, but, like the African race, has become greatly modified by mixture with alien peoples, largely of Malay origin.

Its purest type is to be found in New Guinea, where it approaches the negro in general character, though with distinctive features of its own.

The Papuan is of medium height; fleshy rather than muscular; color a sooty brown; forehead high, but narrow and retreating; nose sometimes flat and wide at nostrils, but oftener hooked with depressed point; lips thick and projecting; high cheek bones; prognathism general; hair black and frizzly. He is negroid in appearance, and is said to resemble the African of the coast region opposite Aden.

We need not pursue this subject further. It will suffice to offer the general conclusion that the negroid race, while, through its change of habits from the hunting to the agricultural status, it has made an advance both mentally and physically beyond the Pygmy aborigines, does not appear to have advanced greatly in either particular, the negro reaching a mental limit at a low level, and being arrested physically while still possessing marked characteristics of the man-ape.

For the higher development of man, under the stress of a more energetic conflict with the conditions of nature, we must seek the continent of Europe, whose human inhabitants had not only to subdue the wild beasts and teach the earth to bring forth wholesome food in place of useless plants, but also to battle with wintry climates, and overcome the adverse influences of cold, sterility of soil, and other hostile conditions of the northern zones.

One of the chief problems of biology has long been that of the production of new varieties and species of animals as an effect of gradual variation in structure. This is believed to be ordinarily due to changes in the conditions of nature, animals and plants which have made accordant changes in structure being preserved, those which have not changed in accordance with the new conditions peris.h.i.+ng. Where the conditions of nature remain uniform, species may persist for long ages unchanged, though even in the latter case changes in structure are apt to occur, since variation in species is not wholly dependent upon external changes. To a considerable extent it is due to causes existing within the organism itself, fortuitous variations being occasionally preserved when not out of harmony with the state of affairs prevailing in the external world. Or variation may occur through the establishment of new relations between the species inhabiting some locality while inanimate nature remains uniform, or through migration into new inanimate or animate surroundings. Variations, in short, may arise under the influence of any change in the general environment which renders necessary adaptive changes in structure. But this adaptation in some cases takes place in the mind, new actions or methods of meeting the contingency being adopted which render physical changes unnecessary. The problem is a highly complicated one, and no doubt many causes have to do with the multiplicity of effects.

There have very likely been many occasions where the changes in structure took place rapidly, in consequence of sudden variations in natural conditions. Such rapid changes in conditions necessarily exert a severe stress or strain on organisms, either destroying them or causing an equally rapid adaptation, physical or mental. In such instances it is likely that many species perish, the change demanded being too great; others escape by migration to better fitted localities; and others, more mobile or less affected by the change, survive through adaptive variations.

Of such periods of strain upon organic nature we know of only one in recent geological times, that known as the Glacial Age, the vast variation in climate which took place when the ice of the Far North flowed down in mighty billows over northern Europe and America, burying everything beneath its crus.h.i.+ng weight, and bringing many forms of life to a sudden and untimely end. No doubt a considerable number of species of animals and plants perished before this frightful invasion. A notable instance among these was perhaps that of the American horse, which disappeared at about this period. Other species survived by a retreat to more tropical regions, to return after the invasion had spent its force.

Still others may have survived by adapting themselves to the changed conditions, emerging as new species or well-marked varieties.

Among the beings which pa.s.sed unscathed through this extraordinary change in climate was apparently man. And it seems safe to affirm that man's contest with the glacial conditions, whose force was exerted upon his mind instead of on his body, was one of the most potent influences in the evolution of the human race. Man entered the contest at a low level of mental development; he emerged from it at a comparatively high level.

No one to-day questions that man was an inhabitant of Europe during the Glacial Age. The proofs of this are too numerous and positive to be doubted. He may have inhabited America in the same period, though of this there still remains some doubt. Claims have been made of the discovery of evidences of man in Europe long before the glacial epoch, reaching as far back as the Pliocene and even the Miocene Age. But these claims have not been established beyond question, and the earliest generally acknowledged traces of man are confined to glacial Europe.

Yet we are forced to acknowledge that if man existed in Europe during the prevalence of the ice age, he, or his ancestor, must have been there before that period. It is absolutely certain that no animal accustomed to tropical conditions would have chosen this period of extreme cold to migrate from the warm tropics to the frozen north. The fact that man was in Europe during glacial times is the very strongest evidence that he reached there during the milder preceding period, when a genial and uniform climate is believed to have prevailed throughout southern and central Europe. If we could accept as fact the seeming very ancient evidences of man's handiwork, we would be obliged to consider him an inmate of Europe long ages before the glacial epoch.

If, as there is reason to believe, the man of Africa at that remote period was the ancestor of the forest-dwelling Pygmy of to-day, lower in mental level and more b.e.s.t.i.a.l in aspect than any of his descendants, yet much advanced in mind beyond the man-ape of earlier ages, then we may with some a.s.surance accept this as the type of the primitive man of Europe. He could have reached there by the land bridges which are thought to have connected Europe and Africa at that time, one closing the straits at Gibraltar, the other extending south from Italy by way of Sicily. These were the routes by which the apes are supposed to have entered Europe, and by which man may well have followed in a later age.

It is possible, indeed, that man reached the northern continent from another locality, the habitat of the Negrito race in southeastern Asia and the Malaysian islands. The fossil man-ape of Java, Pithecanthropus, is a strong argument that this was the region, or one of the regions, in which the development of man took place. However this be, we can be a.s.sured that primitive man was far more likely to widen his field of occupation through migration than any other animal, and may conjecture that he spread over Europe and Asia in the mild preglacial times, and perhaps even reached America, giving rise to the early man of that hemisphere.

The advent of man in Europe was not probably followed by any considerable intellectual development. The mild and equable climate which at that time seems to have prevailed, was not likely to make a stringent demand on his mental resources. Food was very likely abundant and easily obtained, animals of the chase being plentiful, and edible roots and fruits by no means lacking. Thus he could readily obtain the means of subsistence by aid of the arts and weapons employed by him in the tropical forests. It is not unlikely that some changes, both physical and mental, took place, but these were probably not great.

There may have been some change in color and form, a first step toward the distinctions which separate the white from the black man, and a degree of mental adaptation to certain exigencies of the new situation; but in neither direction were the variations likely to be very decided.

Such, as we conceive it, was the man of early Europe, in great measure a counterpart of the forest nomad of the tropics of Africa and the East, the monarch of the animal kingdom, but not the lord of the earth. He may have made some progress in the contest with inanimate nature. Vegetable food in his new home was less abundant than in his old, and the instigation to agricultural pursuits was stronger. And though Europe was thickly wooded, it probably presented more open land than Africa. Both the incitement to agriculture and the facilities for its exercise were, in all probability, greater than in Africa, and man may have begun to cultivate the earth here at an earlier date than in his native realm. We are free at least to speculate that European man gained some slight knowledge of agriculture in the pre-glacial period, but this is doubtful, and the relics of early man yield no evidence in its favor.

Mentally it is questionable if he was advanced beyond the level of the least developed negro tribes, and perhaps not beyond that of the forest pygmies.

But at length the shadow of a mighty coming change began to fall upon the fair face of Europe. Year by year the winters grew colder. The ice sheet, which was in time to bury half of Europe under its chilly mantle, had begun its slow movement toward the south. It advanced very slowly.

Centuries elapsed during its deliberate march. Had it moved with rapidity, few animals could have survived its effects. Some of them found time for changes in structure to fit themselves to the new conditions. Others perished as the wintry chill increased. Const.i.tuted for tropical warmth, they were unable to endure severe cold. The apes and monkeys may have been among the early victims. To-day the apes of Gibraltar are the only ones existing in a wild state in Europe, and it is doubtful if they are of an original stock. There is good reason to believe that escape by migration southward was cut off by the sinking of the ancient land bridges, so that the animals north of the Mediterranean had no choice between adaptation and annihilation.

Among the animals thus taken prisoner by the glacial chill was European man. He could not escape, and was forced to remain, exposed to the alternatives of peris.h.i.+ng from cold and hunger, or fitting himself to endure the new conditions which were coming upon his northern home, perhaps the most adverse to animal life that had ever been known. Man was about to be subjected to an extraordinary strain, which he could only meet by an extraordinary adaptation.

The changes by which he met these new conditions were in a very small degree physical; they were almost wholly mental. In all animals of the higher orders, adaptive variations are apt to be in a measure of this character, the body being relieved from the need of structural change through some new activity of the mind. In man this was undoubtedly the case in great, probably in very great, measure. There may have been an increase in size and strength, some variations in color, in the breathing organs, in power of resistance of the cuticle to cold, etc., but the princ.i.p.al physical change was in a growth of the brain and expansion of the cranium, giving rise to a less b.e.s.t.i.a.l physiognomy and an advanced mental power.

One physical change that would seem necessary to enable an animal to endure severe cold, the development of a thick protective covering of fur or hair, did not take place in man. The change was more likely in the other direction, since the hairy cover which is possessed by many of the forest folk has disappeared. This loss of hair by man has been referred by Darwin to s.e.xual selection, that powerful influence to which animals seem to owe so many physical structures of no apparent use, and some of them seemingly disadvantageous. In the case of man in the circ.u.mstances now under consideration, exposed without natural covering to the growing chill of the advancing ice sheet, the influence of s.e.xual selection would certainly have found a strong counteracting force in natural selection, had not some other means of escaping the influence of the cold been found.

As it was, the difficulty was undoubtedly overcame in great measure by the adoption of artificial clothing. The mind came to the aid of the body. The man who could chip a stone into the shape of an axe or spear head, was sufficiently advanced mentally to conceive the idea of covering his body with leaves fastened together in some way, with other vegetable fabrics, or with the skins of slain animals. Protection from the cold was also sought in caverns and rock shelters, and for a very long period man remained a cave-dweller. There is hardly a cavern in western Europe in which he has not left some trace of his residence.

Where caves were not available, rude artificial shelters were probably built. Even the orang builds a shelter of this kind, and we can readily conceive of man at a very early period making himself a shelter of leaves and boughs, from which, as the cold increased, he might easily evolve a hut composed of a wooden framework covered with skins such as he used for clothing.