Of this there is but little danger, as ethnology will show. There will not be, under any ordinary circumstances, any intermingling of the two races, for the law of ethnic repugnance is too great. The strong ethnic antipathies will keep them apart. The possibility of the intermixture of families and races so widely remote is as rigidly limited as the law of chemical proportions, and the absorption of the minor quantity is inevitable. Give both races the same field for expansion in these States, and the white race will soon find itself in the minority, both of numbers and in physical strength; for, according to natural laws, the stronger blood always absorbs the weaker when there is unobstructed action, and especially when climate favors vastly one of the contending types. There are to-day four or five times as many centenarians among the blacks as there are among the whites of the cotton regions. In consideration of this subject of miscegenation, let us review the phenomena that have been brought to light by the naturalists who have studied hybridity among animals, and recall a few facts from history to support the experimentalists. XVI. In the animal world, in the wild state, hybrids are rarely if ever produced, and it is only from the experiments of the naturalists that the law of hybridity has been explained. We see the bipartites appear, when two kindred species mix together under the influence of man, these animals partaking of the qualities of both. The horse and the ass; the ass, zebra, and hermione; the wolf and the dog; the dog and the jackal; the goat and the ram; the deer and the axis, &c., unite and breed; but these artificial species are not durable, and they have only limited fecundity. "The mongrels of the dog and the wolf are sterile from the third generation. The mongrels of the jackal and the dog are so from the fourth. Moreover, if we unite these mongrels to one of the two primitive species, they soon revert completely and totally to that species. "The mongrel of the dog and jackal contains more of the jackal than the dog. It has the straight ears, the pendent tail; it does not bark; it is wild. It is more jackal than dog. This is the first product of the crossed union of the dog with the jackal. I continue to unite the successive produce, from generation to generation, with one of the two primitive roots,--with that of the dog, for example. "The mongrel of the second generation does not bark yet, but it has the ears pendent at the tip: it is less wild.