The foregoing facts ill.u.s.trate the conclusive evidence brought forward by science that human evolution in physical respects is true. Even if we wished to do so, we cannot do away with the facts of structure and development and fossil history, nor is there any other explanation more reasonable than evolution for these facts. If now we should inquire into the causes of this process, we would find again that the present study of man and men reveals their subjection to the laws of nature which accomplish evolution elsewhere in the organic world.
The fact of human variation requires no elucidation; it is as real for men as for insects and trees. Indeed, some of the most significant facts of variation have been first made out in the case of the human species. The struggle for existence can be seen in everyday life. We cannot doubt its reality when scores perish annually because of their failure to withstand the extreme degrees of temperature during midwinter and midsummer; when starvation causes so many deaths, and when the incessant combat with bacterial enemies alone brings the list of casualties on the human side in our own country to more than two hundred and fifty thousand a year. As in nature at large, the more unfit are eliminated as a result of this struggle, while the more adapted succeed. In the long run, that particular applicant for a clerkship or any other work who may be the more fitted is the one who gets it. While the severity of compet.i.tion may be somewhat mitigated as the result of social organization, and while our altruistic charitable inst.i.tutions enable many to prolong a more or less efficient existence, the struggle for existence cannot be entirely done away with.
Heredity also is a real human process, and it follows the same course as in animals at large; as in the case of variation, some of the fundamental laws of its operation have been first worked out in the case of human phenomena, and have been found subsequently to be of general application.
Reverting to the specific question as to the earliest divergence of man from the apes, we can readily see how the superior development of the ape-man"s brain gave him a great advantage over his nearest compet.i.tors, and how truly human ingenuity enabled the earliest men to employ weapons and crude instruments instead of brute force. Thus the gap between men and apes widened more and more, as reasoning power increased through successive generations. This is another aspect of the statement that the supreme position of man has been gained, not by superior organization in physical respects outside of the nervous system, but by the superior control of human organization by the higher organs of this system.
The unity of nature and of its processes is established more and more surely as the naturalist cla.s.sifies the facts of structure, development, fossil history, and evolutionary method. Our own species is not unique; it takes its high place among other organic forms whose lives are controlled in every way by the uniform consistent laws of the world.
The physical evolution of human races is the next major division of the large subject before us. Heretofore the obvious differences displayed by various races have been disregarded and the species has been treated as a unit, in order that its evolution from pre-human ancestors might be made clear. Knowing now how the facts of structure show that the supreme position of our kind has been attained mainly as the result of the progressive elaboration of the higher portions of the brain, and not because new and unique structures have been developed, we are prepared to turn our attention to the diverse characteristics of human races; and during this inquiry anatomical matters will still be the only ones to be reviewed. The intellectual and social characters of numerous races belong to the category of physiological or functional phenomena, which are to receive due consideration at a later time. It is the meaning of the facts of racial diversity for which we are now to look.
For many reasons this subject is more difficult to describe in a concise outline than those taken up before. It is true that every one is familiar with different types of human beings, such as the Negro and j.a.panese and Chinese, while furthermore the obvious differences between such races as the Norwegian and Italian are sufficiently marked to strike the attention of any one who looks about at his fellow-pa.s.sengers in a crowded street car. But few indeed have a comprehensive knowledge of the wider range of racial variation in which these familiar examples find their place.
Anthropology, or the science of mankind, is a large and well-organized department of knowledge, dealing with the entire array of structural and physiological characters of all men. One of its subdivisions, anthropometry, is almost an independent discipline with methods of its own; it describes the characteristics of human races as these are determined by statistical methods of a somewhat technical nature. There is still another science, ethnology, which deals more particularly with inst.i.tutions, customs, beliefs, and languages rather than with physical matters, although it is clear that ethnology and anthropology cannot be sharply separated, and that each must employ the results of the other for its own particular purposes.
Because men have always been interested in the study of themselves, the subject of racial evolution is literally enormous, and the attempt to give anything like a complete description of what is known would obviously be futile. But it is possible to obtain a clear conception of certain of the fundamental principles that fall into line with the other parts of the doctrine of organic evolution with which we have now become acquainted.
The main questions, therefore, may be stated in simple terms. The first deals with the evidences as to the reality of evolution during the historical and prehistoric development of the various types of man from earlier common ancestors; the second asks whether the lines of racial evolution are further continuations of the line leading from ape-like ancestors to the human species as a type. In order to give the proper perspective, it will be well to state at the present juncture, first, that the various kinds of men do not vary from each other in a chance manner so as to show all possible types and varieties, but that they fall into natural groups or families distinguished by certain common characteristics, just as do all other kinds of species of animals; in the second place, it appears that some of the differences between the races denoted higher on structural accounts and the lowest forms of man are of the same nature as those observed in the review of the various species of primates from the lemurs to man.
It is best to look at the whole question in a very simple and common-sense way before undertaking an extended examination of the details of human diversity. The most casual survey of the peoples that we know best because of our own individual nearness to them enables us to realize that the races now upon the earth have not existed forever and ever, or even for the age of 6000 years as contended by Archbishop Ussher. They have all come into existence as such, and they differ from their known antecedents; so that at the very outset common-sense leads us to accept evolution as true, if we admit that human races have changed during the course of recent centuries. We know, for example, that the so-called Mexicans of to-day are a people produced by a fusion of Spanish conquerors and Indian aborigines the Mexican is neither Spaniard nor Indian, though he may resemble both in certain respects; he is a product of natural evolution, accomplished in this case by an amalgamation of two contrasted types. When we speak of the American people, we must realize that it too has come into existence as such, and even, indeed, that it is in the actual process of evolution at the present time. The various foreign elements that have been added during the last few decades by the hundreds of thousands are becoming merged with the people who preceded them, just as the Dutch and the French and the English coalesced during the days of early settlement to form the young American nation. Perhaps most of us call ourselves Anglo-Saxon, but we are in reality somewhat different even in physical respects from the Englishmen of Queen Elizabeth"s time, who alone deserved the name Anglo-Saxon. This very term indicates an evolution of a type that differs from both the Angles and the early Saxons of King Alfred"s age.
These are simple examples which ill.u.s.trate many features of the universal history of human races wherever they are to be found. Even in the comparatively peaceful times of our modern era the history of any race is a veritable turmoil of constant changes; conquerors impress their characters upon the vanquished, while the victors often adopt some of the features of the conquered. Colonies split off from the mother nation to follow out their destinies under other conditions. Nowhere does the naturalist find evidence of long-established permanence, or an unentwined course of an uninterrupted and unmodified line of racial descent.
It is the task of the student of human evolution to unravel the tangled threads of human histories. The task is relatively simple when it is concerned with recent times where the aid of written history may be summoned but when the events of remote and prehistoric ages are to be placed in order, the difficulties seem well-nigh insuperable. All is not known, nor can it ever be known; but wherever facts can be established, science can deal with them. By a study of the present races of mankind, much of their earlier history can be worked out, for their genetic relations may be determined by employing the principle that likeness means consanguinity. Let us suppose an alien visitor to reach our planet from somewhere else; if he were endowed with only ordinary human common-sense, he would very soon ascertain the common origin of the English-speaking people in Canada, the United States, Australia and New Zealand, South Africa, and many other places. Even if he could not understand a word of the English language, he would be justified in regarding them all as the descendants of common ancestors because they agree in so many physical qualities. The anthropologist works according to the same common-sense principle, obtaining results that find no explanation other than evolution when the varying characters that are used to determine social relationship are properly cla.s.sified and related. It is to these characters that we must now give some attention.
The average stature of adults varies in different races from four feet one inch in certain blacks to nearly six feet and seven inches, as among the Patagonians. These are the extreme values for normal averages, although dwarfs only fifteen inches high have been known, while "giants" sometimes occur with a height of nine feet and five inches. Such individuals are of course rare and abnormal, and are not to be taken into account in establishing the average stature of a race for use in comparison with that of another group.
The color of the skin is another criterion of racial relationship, though it is more variable in races of common descent than we are wont to a.s.sume.
We are familiar with the fair and florid skin of the northern European, the fair and pale skin in middle and southern Europe, the coppery red of the American Indian, the brown of the Malay, of the Polynesian and of the Moor, the yellowish cast of the Chinese and j.a.panese, and the deeper velvety black of the Zulu; but it has been found that many of the close relatives of the black are lighter in skin color than some of our Caucasian relatives, so that this character cannot be taken by itself as a single criterion of racial affinity.
Perhaps the most conservative and most reliable character that serves for the broad cla.s.sification of the human races is the shape of the individual hairs of the head. We are familiar with the straight lank hair of the Mongolian peoples and of the various tribes of American Indians, in whom the hair possesses these peculiarities because each element grows as a nearly perfect cylinder from the cells of the skin at the bottom of a tiny pit or hair-follicle. The familiar wavy hair of white men owes its character to the fact that the individual elements are formed by the skin, not as pencil-like rods, but as flattened cylinders. They are oval or elliptical in cross-section, and when they emerge from the skin they grow into a long spiral. If, now, the hair is formed as a very much flattened rod about one-half as wide in one diameter as in the other, it curls into a very tight close spiral and gives the frizzly or woolly head-covering of the Papuan and of the Negro.
In the next place, the shape of the cranium is a character of much value.
This is determined as the proportion between the transverse diameter of the skull above the ears to the long diameter, namely, the line that runs from the middle of the brow to the most posterior point of the skull. In the so-called "long-headed" or dolichocephalic races, the proportion is seventy-five to one hundred, while in those forms that have more rounded or brachycephalic heads, like the Polynesian and the black pygmy, the relation is eighty-three to one hundred. The cranial capacity again varies considerably, from nine hundred cubic centimeters to twenty-two hundred cubic centimeters. Many striking variations are also found in the projection of the jaws. A line drawn from the lower end of the nose to the chin makes a certain angle with the line drawn from the chin to the posterior end of the lower jaw; if the jaw projects very greatly, this angle will be much less than when they do not. In most of the Caucasian peoples, the lines meet at an angle of eighty-nine degrees, or very nearly a right angle, but in some of the lower races the figure may be only fifty-one degrees. Additional characters of the teeth and of the palate are also taken into account, and have proved their utility. Finally, the nose exhibits a wide range of variation from the small delicate feature of the Chinaman to the large, well-arched nose of the Indian. It may be hollowed out at the bridge instead of arched; again, it may be nearly an equilateral triangle in outline, as in the Veddahs, and the nostrils may open somewhat forward instead of downward. As many as fifteen distinct varieties of the human nose have been catalogued by Bertillon.
These are the princ.i.p.al bodily characters which the anthropologist uses to distinguish races and by their means to determine the more immediate or remote community of origin of comparable types. Many of these characteristics, as indeed we may already see, are decidedly important in connection with the second problem specified above, for in the case of the flat triangular nose and projecting jaws of a low negroid we may discern clear resemblances to certain features of the apes.
Long before the doctrine of evolution was understood and adopted, students of the human races had been deeply impressed by their natural resemblances. As early as 1672 Bernier divided human beings according to certain of these fundamental similarities into four groups; namely, the white European, the black African, the yellow Asiatic, and the Laplander.
Linnaeus, in the eighteenth century, included _h.o.m.o sapiens_ in his list of species, recognizing four subspecies in the European, Asiatic, African, and Indian of America. Blumenbach in 1775 added the Malay, thus giving the five types that most of us learned in our school days. But the different varieties of men recognized by these observers were believed to be created in their modern forms and with their present-day characteristics; the common character of skin color exhibited by any group of peoples of a single continent was to them only a convenient label for purposes of description and cla.s.sification. It was not until years later that fundamental resemblances were recognized as indicating an actual blood relationship of the races displaying them, and therefore of evolution.
Since the doctrine of human descent and of the divergence of human races in later evolution has been accepted, those who have attempted to work out fully the complete ancestry of different peoples have found that no single character can be taken by itself, while the various criteria themselves differ in reliability; the color of the skin is not so sure a guide as the character of the hair and skull, wherefore the cla.s.sifications of recent times, notably those of Huxley and Haeckel, have been based largely upon the latter. The latest systems have been more rigidly scientific and more in accord with the most modern conceptions of organic relationships in general, as evidenced by the thoroughgoing methods of Duckworth in his recent treatise on human cla.s.sification.
It now remains to present the salient facts regarding the genetic relationships of typical human races, although it is obviously impossible to go into all of the details of the subject. But these are not essential for the main purpose, which is to show that the evolutionary explanation is the only one that is reasonable and self-consistent. Opinions are sometimes widely at variance regarding countless minor points, but no anthropologist of to-day can be anything but an evolutionist, because the main principles upon which the specialists agree fall directly into line with those established elsewhere in zoology. It seems best to state these principles without reverting to controversial matters which find their place in the monographs of the experts. Any comprehensive account such as that of Keane, even if it may not give the final word, will be entirely sufficient to demonstrate how fruitful are the methods of evolution when they are employed for the study of human races, and indeed how impossible it is to discuss human histories without finding conclusive evidences of their evolutionary nature.
The facts that are available indicate that the first members of our species evolved in an equatorial continent which is now submerged, and which occupied a position between the present continents of Asia and Africa. From this center hordes of primitive men migrated to distant centers where they differentiated into three primary and distinct groups.
The first of these was gradually resolved into the darker-skinned peoples most of whom now live in the continent of Africa, although many dwell also in the islands of the western Pacific Ocean. The second branch divided almost immediately to produce, on the one hand, the Indians of the new world and, on the other, the yellow-skinned inhabitants of Asia and other places. The third branch developed as such in the neighborhood of the Mediterranean Sea, and produced the series of so-called Caucasian peoples, which are by far the most familiar to us and to which most of us belong.
But so early did the second branch divide that there are virtually four main divisions of the human species that are to be examined in serial order.
It is best to begin with our own division, because its greater familiarity makes it easier to become acquainted with the methods and results of anthropology, on the basis of facts that we already know. Three subordinate types exist, located primarily in northern, central, and southern Europe respectively, but many other races dwell elsewhere that are a.s.signable to one or another of these subdivisions. In northeastern Europe we find people such as the Norwegians, Swedes, Danes, and north Germans, that average five feet eight inches in height. They have the long, wavy, and soft hair which is a general characteristic of the whole Caucasian group, although its light flaxen color is distinctive. The blue eye and florid complexion accompany the light color of the hair. The skull is of the longer type, the jaws and forehead are straight and square, the nose is large and long without a distinct arch, and the teeth are relatively small. It is not so well known that the Scandinavian type is so closely copied by many people of Asia, such as the western Persians, Afghans, and certain of the Hindus, living in a continent that we are inclined to a.s.sign to the Mongol only. In the possession of these characters the Northern Europeans and other races specified display evidences of their common ancestry and evolution quite as conclusively as in the case of the cats discussed in an earlier chapter where the meaning of essential likeness was first demonstrated.
A broad zone may be drawn from Wales, across Europe and Asia, and even to the eastern islands of the South Seas, in which we find peoples that are obviously of Caucasian descent, but they differ from the members of the first group in some details of structure. On the average they are about five feet five or six inches in height, the hair is dark and wavy, but it is not the pencil-like structure of the Mongol. The complexion is pale, the skull is rounder, and the eyes are usually brown in color. These peoples agree also in their volatile temperament and vivacious manner and are thus markedly different from the more stolid northerners. To this minor branch of the Caucasian stock belong the Welsh, most of the French, South Germans and Swiss, Russians and Poles, Armenians, eastern Persians, and finally some of the inhabitants of Polynesia. The last, it is true, form a well-marked group of darker-skinned and taller races, but in spite of the admixture of these and other unusual features, we can still discern the bodily characters that supplement their traditions, telling of an Asian origin, in demonstrating their common ancestry with round-headed Persians and middle Europeans. Below the zone of middle Europe and Asia is another broad region inhabited by the "Mediterranean" type of Caucasian.
The Spaniard, Italian, Greek, and Arab are sufficiently familiar to ill.u.s.trate the distinctive qualities of this subdivision. These people have the smaller stature, dark hair, dark eyes, and paler skin of the middle Europeans, but the skull is of the long instead of the rounded type. A well-marked subordinate group is formed by the so-called Semitic peoples, such as the Arabs and their Hebrew relatives. The Berbers and other North African races possess a darker skin probably because of the admixture of Ethiopian stock, and they, too, are so well characterized that they form a clearly marked outlying group as the so-called Hamites.
Pa.s.sing over into Asia we find relatives of the Mediterranean man in the Dravidas and Todas of India, possibly in the degenerate Veddahs of Ceylon, and finally in the Ainus or "hairy men" of some of the j.a.panese islands.
The last-named people certainly possess some Mongolian features, but these seem to have been added to a more fundamental form of body that is distinctly Caucasian.
All of the races we have mentioned, together with their relatives, may be compared to the leaves borne upon three branches that take their origin from a single limb of the widespread human part of the tree. They cannot be cla.s.sified in any mode on the basis of their primary and secondary resemblances without employing the treelike plan of arrangement, which to the man of science is a sure indication of their evolutionary relationships.
The people of the second or Mongolian group agree in certain well-marked characteristics in such a way as to be well separated from the other divisions of mankind; these characteristics we may speak of as const.i.tuting a second "theme," of which the various peoples of the group are so many variations. To visualize them we need only to recall the appearance of the Chinaman, perhaps the most familiar example of the entire series. Here the hair is coa.r.s.e and black, and straight because of its round transverse section; the mustache and beard of the Caucasians are seldom found except in later life; the skin is a fleshy yellow in color; the skull is round, indeed, it is one of the roundest that we know; the jaws are not so straight as in the Caucasian, for the angle at the point of the chin is about sixty-eight degrees. The cheek bones project laterally, with greater or less prominence; the nose is very small, tilted up slightly at the end, and is usually hollowed instead of arched. The eyes are small and black in color, set somewhat obliquely, and the upper lid is drawn down over the eye at its inner corner so as to make the obliquity still more marked. The teeth are larger than those of the Caucasian. Finally, the Mongol is below the average of all men as regards height, being usually about five feet four inches tall.
The original Mongolians probably developed the characteristic features we have just noted in a Central Asiatic region, and then almost immediately they divided into two great groups. Each of these evolved along certain lines of its own, one sweeping northward to develop into what are now called the Northern Mongols, the other working its way eastward and southward to produce the peoples of China proper, Indo-China, and many parts of Malaysia. Considering first the peoples of the Northern Mongolian division, we find in the typical Manchurian what is perhaps the nearest among modern people to the original race. Spreading northward and westward from the middle Asiatic plains, this great wave has produced the nomadic tribes of Siberia, like the Chukchi, the Buryats, and the Yukaghir. The present inhabitants of Turkestan connect those forms which have remained near the original home with the races of Mongolian origin that live farther to the westward, like the Turks of Asia. But the Mongolian tide originally swept much farther to the west, although it was driven back later by conquering Caucasian peoples; and it has left behind such remnants as the Finlander and the Laplander, the Bulgar, and the Magyar.
It is evident that these western branches of the Mongol stock are not at all pure in their racial characteristics, for they clearly show the effects of a mixture with alien European peoples. To a.s.sign them to the Northern Mongol division means only that their dominant characteristics are mainly those of Mongolian nature. We have referred the Russians to the middle Caucasian division even though the Slav or Tartar infusion is very great, but it does not dominate over the Caucasian peculiarities as it does in the case of the peoples we have mentioned. As regards the remaining types we must add to this brief list the Koreans and the j.a.panese, the former being far purer in Mongolian nature than the latter people, which has apparently been affected by a Malay influence from the south.
Turning now to the southern Mongol, we find that from their cradle in the Tibetan plateau they too have spread widely, and their descendants have also come to differ in certain respects as they have established themselves in other lands. Most of the present people of Tibet belong to this section; the Gurkhas of Hindustan, the people of Burma proper, of Annam, and Cochin China are close relatives of one another and of the more characteristic Mongolians of China proper who make up the vast bulk of the population. From this stock we may also derive the Malays of Sumatra and Java, of Borneo and Celebes, and the Tagals and Bisayans of the Philippine Islands. Even the Hovars and other tribes of Madagascar may be referred to this division, for although in them the skin has become somewhat darker, we may still discern the characteristics which indicate their common ancestry with the Oceanic Mongols.
The American Indians taken collectively const.i.tute a group that is well set off from the rest of mankind by such characters as taller stature, small, straight, and black eyes, a large nose that is usually bridged or aquiline, a skull of medium roundness, and the yellow copper color of the skin. The common origin with the Mongols is demonstrated by the straight and long, coa.r.s.e, black hair and by the absence of a beard; the mustache also is almost always absent.
All of us have seen Indians belonging to the tribes of the plains, which serve as excellent examples of this grand division. Many have also visited the homes of the Pueblo Indians, and have learned how uniform is the physical appearance of the tribes living in various parts of the United States. Indeed throughout all of North America the basic characteristics of Indians prove to be strikingly conservative, although in the Eskimo there are some departures which seem to indicate a closer connection of these peoples with the Mongols, probably as the result of some more recent influx from the neighboring and not very distant region of northeastern Siberia. Extending our survey southward through Central America, the Aztecs and Mayas are found to possess many of the same characters, though in some respects they are transitional to the Caribs of the northern edge of South America and to the Indians of South America. Traveling still farther southward, we meet the very tall Patagonian, still an Indian in essential respects, and finally, the Yahgan and Alacaluf of the Fuegian region, the most degenerate members of the race. The last-mentioned people are dull and brutish and most degraded in all respects, and stand at the lowest end of the red Indian series as regards intellectual ability and cultural attainment.
We now come to the last of the four great divisions of the human species which includes the races usually spoken of as Africans or Ethiopians. But these races are by no means restricted to the continent of Africa, for quite as typical black types are found in far-distant lands such as Australia and many islands of the Pacific Ocean. The races a.s.signed to this division group themselves about two subordinate types,--the tall negro proper and the shorter or dwarf negrito,--and each of these has representatives both in Africa and in the oceanic territory.
The black slaves of America were all descended from typical negros brought from the western part of Africa, and they provide us with adequate ill.u.s.trations of Ethiopians as a group. In them the stature is above the average of men in general, specifically about five feet ten inches. The short jet-black hair is strikingly different from the head covering of the other great groups of human races; each individual hair is so flat in cross-section that it curls into a very tight close spiral, and this brings about a frizzly appearance of the whole head covering. There is little or no beard, the skin is soft and velvety and of various shades approaching black in color. The skull is long, the cheek bones are small, but the most distinctive characteristics of the head are found in the apelike ridges over the eyes and in the very broad flat nose which projects only slightly and turns up so that the nostrils open forward to a marked degree, while in the jaws there is an astonishing divergence from the Caucasian condition in the great protrusion which causes the angle at the chin to be about sixty degrees.
The warlike Zulus and other peoples of Southern and Central Africa are perhaps the most characteristic races in this division. Their relatives are found to the northward as far as the Sahara desert, along the southern borders of which they have spread out to the eastward and westward. Fusion with other races has taken place along this border so that many of these northern tribes are much lighter than the Zulus in the color of the skin.
But many relatives of the taller African negro are found in other parts of the world, namely in Australia, and in New Hebrides and New Caledonia--islands to the north and east of this continent. The Papuan of New Guinea is a typical negro in all true respects, with strongly marked Ethiopian characteristics, though there are some differences which are transitional to the more aberrant natives of Melanesia, which includes many archipelagos like the Fiji, Bismarck, Marshall, and Solomon islands.
Undoubtedly the most degenerate member of the tall negro division is the Australian native, the so-called "blackfellow." The bulbous nose and the well-grown beard mark him off from the typical stock, but his obvious relationship to this is indicated by the low brain capacity, the prominent ridges over the eyes, and the heavy projecting jaws.
Taking up the other division of the so-called Ethiopian race, const.i.tuting the Negrito section, we may begin with its Oceanic members. The natives of the Andaman Islands, the Kalangs and the Sakais of Java and neighboring regions, and the Aetas of the Philippine Islands agree in a dwarfed stature of four feet or a little over, in their yellowish brown skin color, a round head, and woolly reddish-brown hair. They, too, possess large ridges over the eyes and extremely prominent jaws, and in these latter characteristics particularly we see evidences of their relationship to the negro. But perhaps the most characteristic pygmies are found in Africa. The little Bushmen and Hottentots are low types of the Negrito stock, and they lead us to the lowest men of all, the Akkas of the West Congo region. It is difficult for us to realize how utterly degenerate and apelike these pygmies are. The jaws are disproportionately large as compared with the cranium or brain-case, and project to a degree which brings the skull very close to that of the higher apes; while in mental respects, in the absence of dwellings, and in many other ways they prove to be the lowest of all mankind,--veritable brutes in form and mode of life.
Without a full series of photographs before us the foregoing sketch of the various races of men cannot make us fully acquainted with all the strange varieties of the human body, but it will suffice to establish two fundamental results. While all men agree in the possession of certain features which set them apart from other members of the primate order, they differ among themselves in such a way as to fall into four well-marked subdivisions branching out from a common starting-point.
Furthermore, in each of these primary groups the subordinate types arrange themselves also in the manner of branches arising from a common limb. This is the relation that we have earlier found to be a universal one throughout the animal kingdom, and science believes that it indicates everywhere an evolutionary history--an actual development along different lines of descent of forms which have a common starting-point and ancestry.
The second principle is perhaps even more significant: when we review the many races from the Caucasian to the dwarf Negrito, we traverse a downward path which will bring us inevitably to the higher apes. In our survey of human races, we have pa.s.sed from the Caucasian, with the largest brain and cranium and with straight jaws well underneath the brain-case, to the pygmy with a relatively small brain, with huge projecting jaws and with prominent ridges over the eyes; one step more along that path would bring us to the gorilla or the chimpanzee. The array of lower primates, from the lemur to the gorilla, gives a series of forms exhibiting a progressive advance in respect to the size of the brain and cranium, and a gradual retreat of the jaws to a position underneath the cranium; and one step further brings us to man. In a word, these two lines join--in fact, they are directly continuous. There is a far smaller difference between the lowest man and the highest ape than we have been accustomed to suppose.
Thus in general terms, it can justly be said that process of evolution which developed the first man from its ape-man progenitor seems to have continued during subsequent ages. Spreading out in diverging lines of evolutionary descent no less clearly than they have in geographical respects, certain races have far surpa.s.sed their fellows of a lower order, which, like the brute pygmy, remain nearer the common structural form from which all men have sprung.