Polar races of Asia, which are part of the Mongolian tribes, covering the immense region extending from the line of the Ural and Himmaleh mountains to Behring's Straits.

But before proceeding to a consideration of the characteristics of the American Aborigines, as connected with the question of the unity of the human family, let us first treat of the phenomena of hybridity, which have a close relation with the determination of species. An identity of species between two animals, notwithstanding a striking difference in some particulars, has been inferred, as a general rule, if their offspring has been found capable of procreating. Although this doctrine has been generally maintained by our most distinguished naturalists, yet some have rejected it as a hasty generalization. The production of hybrids is a phenomenon observed not only among mammifers, but among birds, fishes, the insect tribes, and the vegetable kingdom; and when we survey the numerous facts opposed to the generally admitted law of nature that all hybrid productions are sterile, there would seem to be some ground for doubting the soundness of the general conclusion. Thus the dog and the wolf, and the dog and the fox, will breed together, and the mixed offspring is capable of procreating. And that mules are not always barren, is a fact not unknown even to Aristotle. But as hybrid productions are almost unknown among animals in their wild and unrestrained condition, it would seem that there is a mutual repugnance between those of different species; and thus nature guards against a universal confusion of the different departments of oganized creation. Notwithstanding the occasional exceptions to the general fact of the sterility of hybrid productions, it has never been observed that an offspring similar to themselves has proceeded from hybrids of an opposite sex. The offspring of these animals is capable of being continued in successive generations only by returning towards one of the parent tribes. It is thus apparent that the vis procreatrix between different species, both in the animal and vegetable kingdoms, is very defective, and that the law of nature which maintains the diversity of tribes in the organized world, is not really infringed by the isolated phenomena observed in reference to hybrid productions. That animals generally have the same form and endowments now as at the remotest period of our acquaintance with them, is an opinion confirmed by the oldest historical records, as well as by, the works of art and the actual relics found in Egyptian tombs.

The zoological descriptions of Aristotle, composed twentytwo centuries ago, are still faithful to nature in every particular. Hence it would appear that insurmountable barriers to the intermixture of species, at least among wild animals, have been provided by nature, in the instinctive aversion to union with other species, in the sterility of hybrid productions, and in the law of the reproduction of the corporeal and psychical characters of the parent in the offspring.

These facts have an important bearing upon the doctrine that mankind constitutes a single species. It is well known to horticulturists and those engaged in breeding domesticated animals, that, by crossing and intermixing varieties, a mixed breed superior in almost every physical quality to the parent races is often produced; and it has also been observed that the intermixture of different races of the human family has produced one physically superior, generally speaking, to either ancestral race. Now, as it is a law, according to the high authority of Buffon and Hunter, that those animals of opposite sexes, notwithstanding some striking differences in appearance, whose offspring is equally prolific with themselves, belong to one and the same species, it follows that these facts afford a strong confirmation of the conclusion deduced from many others, viz., that there is but one human species, for, as just remarked, while the offspring of distinct species, (real hybrids,) are so little prolific that their stock soon becomes extinct, it is found that the mixed offspring of different varieties of the same species generally exceeds the parent races in corporeal vigor and in the tendency to multiplication. This law, however, does not apply to the moral and intellectual endowments; for we find these deteriorated in the European by the mixture of any other race, and, on the other hand, an infusion of Caucasian blood tends in an equal degree to ennoble these qualities in the other varieties of the human family. It is, indeed, an undisputed fact, that all the races and varieties of mankind are equally capable of propagating their offspring by intermarriage; and that such connexions when contracted between individuals of the most dissimilar varieties, as for instance the Negro and the European, prove, if there is any difference, even more prolific. This tendency to a rapid increase is especially obvious among the so-termed Mulattoes of the West Indies. Upon this point the philosophic Prichard arrives at the following conclusion:

"It appears to me unquestionable that intermediate races of

men exist and are propagated, and that no impediment whatever exists to the perpetuation of mankind when the most dissimilar varieties are blended together. We hence derive a conclusive proof, unless there be in the instance of human races an exception to the universally prevalent law of organized nature, that all the tribes of men are of one family."

It is well remarked by Prichard, that perhaps the solution of the problem of the unity of the human family, might be safely left on this issue, or considered as obtained by this argument. The same law, as is well known, applies to our Aborigines. As we spent upwards of two years, when serving in the Medical Staff of the Army, among the Creeks, Seminoles, and Cherokees, we saw, especially in Florida, the most remarkable intermixtures between the Indian and the Negro, as regards the physiognomy of the individual. Instead of an apparent new being like the Mulatto, the mixed offspring would often exhibit the decided characteristics of the two races, without any obvious blending. Thus, one would have the crisp and curly hair, united with a reddish copper-colored skin and all the other Indian features and another would present the straight, long, and coarse hair of the Indian upon a true Negro skull; as the low and retreating forehead, the projecting jaws, the thick nose, the narrow and retracted chin, and the jet black complexion.

We shall also here bring under notice what may be designated as accidental or congenital varieties, these phenomena having a close relation with the diversities exhibited among the various tribes of mankind. Among all organized productions, we find variety of form and structure in the same species, and even in the offspring of the same parents; and what is equally remarkable, we discover a tendency to perpetuate in their offspring all individual peculiarities. This constitutes, in some degree, an exception to the general law that animals produce their like,an exception by which it were easy to explain the present existence of diversified races, originating from the same primitive species, did not a new difficulty arise in the question, having reference to the extent of deviation of structure that may take place without breaking in upon the characteristic type of the species. There are many instances on record in which these accidental varieties have been perpetuated by hereditary transmission. One of the most extraordinary is the recent origination of a new variety of sheep in the state of Massachusetts, called the "ancon or otter-breed," in consequence of the shortness of

the limbs and the greater proportionate length of the body, the fore-legs being also crooked.

Among instances of variety of structure originating in the race of man, which are in like manner propagated through many generations, may be mentioned the oft-observed fact of supernumerary toes or fingers, and corresponding deficiencies. Hence the names of Varus and Plautus among the ancient Romans. Likewise, those peculiar features by which the individuals of some families are characterized; as, for instance, the singular thickness of the upper lip in the imperial house of Austria, which was introduced, three centuries ago, by intermarriage. These organic peculiarities are often transmitted to children, even when one of the parents is of the ordinary form, for three or four generations. Hence there is reason to believe that if persons of this organic peculiarity were to intermarry exclusively, we might have a permanent race characterized by six toes or fingers. We have a similar fact in the history of the English family of "porcupine men," in whom the greater part of the body was covered with hard excrescences of a horny nature, which were transmitted hereditarily. These remarks apply equally to those peculiarities of organization which predispose to many diseases, as well as to the transmission of mental and moral qualities, all of which are truly hereditary. It is thus seen that varieties of structure are not always transmitted from first parents, and that when they have once arisen, they become, under favorable circumstances, permanent in the stock.

We are now prepared to consider the characteristics of our aboriginal race, by which, in the language of Morton, they "stand isolated from the rest of mankind." We shall speak first of diversities of form or configuration, the most important of which is doubtless the shape of the head as connected with the development of the brain. The classification of skulls under five general forms already given, is of course entirely arbitrary; and as in every other corporeal diversity, so we find in regard to crania an imperceptible gradation among the nations of the earth, filling up the interval between the two extremes of the most perfect Caucasian model and the most exaggerated Negro specimen. Hence we must conclude that the diversities of skulls among mankind, and consequently in a much less degree the peculiarity of our Indian, do not afford sufficient ground for a specific difference-an inference confirmed, as will be seen, by the variations which occur in animals of the same species

We might show, as we think, conclusively, did space allow, that there is a connection between the leading physical characters of human races, (and especially as regards cranial formation,) and the agencies of climate and their habits of existence. This is very apparent in the configuration found in our Aborigines, and equally so in all other races in the nomadic and hunter conditions, consisting of the greater development of the jaws and zygomatic (cheek) bones; in a word, of the bones of the face altogether, as compared with the size of the brain. That the development of the organs of taste and smell, is in an inverse ratio to that of the brain, and consequently to the degree of intelligence, is considered by Bichat as almost a rule in our organization. By this principle, as an index to those exalted prerogatives which elevate man above the brute, was the Grecian sculptor guided. Although, upon this point, the facial angle of Camper is not an exact test, yet it may be remarked that in the human race, it varies from 65° to 85°, the former being a near approach to the monkey species. Among the remains of Grecian art, we find this angle extended to 90° in the representation of poets, sages, legislators, etc., thus showing that the relation here referred to was not unknown to them; while, at the same time, the mouth, nose, jaws, and tongue, were contracted in size, as indicative of a noble and generous nature. In the statues of their gods and heroes, the Greeks gave a still greater exaggeration to the latter, and reduction to the former characteristics, thus extending the forehead over the face, so as to make a facial angle of 100°. It is this that gives to their statuary its high character of sublime beauty. Even among the vulgar, we find the idea of stupidity associated with an elongation of the

snout.

As regards man's average stature, the size and proportions of his trunk and limbs, and the relations of different parts, it has been inferred by some that these varieties, in connection with other diversities, constitute distinctive characters sufficient to class the human family under several separate species. It has been asserted, for instance, that in the Negro the length of the forearm is so much greater than in the European, as to form a real approximation to the character of the ape. This difference, however, is so very slight, compared with the relative length of the arms of the orang and the chimpantsi, that we are not even warranted in the inference that races long civilized have less of the animal in this respect in their physical conformation than