In the tropical parts of the world there are many mammalian species which are worthy subjects for essays in domestication. This is particularly the case in the continent of Africa where, except in the lands about the Mediterranean and the Red Sea, the native peoples have never attained the stage of culture in which men become strongly inclined to subjugate wild animals. Africa is richer in large herbivorous species than any other of the great lands; many of these forms are of large size and have qualities of flesh, of hide, or other peculiar features which promise to make them valuable in an economic way. Others, especially the antelopes, have a beauty of form and a grace of movement which render them among the most attractive creatures of their class. Even the hippopotamus, one of the grossest beasts of this realm, affords in its teeth a valuable ivory, and its hides, if supplied in sufficient quantity, would probably find a considerable use. It is evident that in this "dark continent," where the influences which make for human advancement have been so slight, we have the best field for the selection of species that may hereafter be brought to the use of man. There is evidently danger, in the advance in the civilizing process, that the native forms which, owing to their fitness to the physical conditions of the country, might be made useful to its people, may be utterly destroyed by hunters. Perhaps the most interesting of the tropical beasts from the point of view which we occupy is the elephant: This animal in its relations to men is eminently peculiar, in that while it has been in an individual way long and completely subjugated, it has never been systematically reared in captivity. Owing, it may be, to the slow growth of these great beasts, as well as to the immediate manner in which they submit to their captors, it has ever been the custom to take them when adult from the wilderness. The result is that the supply of the Asiatic species, which alone is serviceable--the African form being apparently too fierce for use--is now dependent on a relatively small number of wild herds. Certain of these herds are protected by the governments of India, but it seems as if the species were already dangerously near the vanishing point--in a position where the invasion of some disease or some insect enemy might deprive the world of what is, all things considered, the most interesting of the brutes. Moreover, the failure to rear elephants in captivity has made it impossible to essay any of those experiments in breeding which have done so much to improve the utility and the beauty of most subjugated forms.