The superiority of mankind, we readily concede, is not determined by shades and shadows; the standard is much higher. But as mind conforms to matter, or matter to mind, mentalities are as diversified as are the shades and colors of human skins. The exterior is but an index of the interior, or life within; consequently, as exteriors differ, so do interiors, and as gradation rises, so do equalities disappear, as the sage, and all intermediate ascendencies, rise above the fool. But nature rises by degrees, and, in the harmony of her adjustments, divides and subdivides her divisions, as by the walls of a prison, from which there can be no escape. She has classified her works into _orders_, _genera_ and _species_, and to each fixed a boundary as immutable as are the stars and the hills. Education may improve, but it never can pass the _specific_ or _generic_ barriers which nature has erected through all her works. The dog which is a _genus_, ranked in the world of letters as the genus _canis_, has his _specific_ divisions, as hound, bull, cur, terrier, and the like—each marked by a peculiarity designating its kind. These may be cultivated, but never changed or overcome. The dog that runs by scent may be cultivated in his powers—may be taught to scent closer and to increase his speed; so, too, may he that runs by sight be improved in the same manner; but neither one can be transformed into the other, for the specific division must continue to the end of time. These laws apply with no greater power to inferior than to superior natures—are no more forcible on the beast than on the man; but, on the contrary, as all nature is divided, the cat, the dog, the horse, the sheep, the goat, the ox and the swine, each into his specific kind, so, too, is divided the _Genus Homo_, or genus man. The number of species of this _genus_—the crowning ultimate of animated things—may, in the present condition of our knowledge, be very imperfectly, if at all, determined. But enough is known to give us, at least, seven varieties of men—the Mongolian, the Malay, the Australian, the Indian, the Arctic, the Negro and the Caucasian—whose divisions are as well marked as the divisions which separate the spaniel from the hound, the tiger from the leopard, or the panther from the cat. Their variances are all diversified, are physical, mental and instinctive, and creative of different wants, so that as one spaniel seeks the water while another shuns it, so do the various species of men require different rules and forms, privileges and restrictions, for the regulation of their aggregation in associated life.