Each and every _specific_ creation is different from every other specific existence, and differs just as widely in the circumstances that surround it, and to which it is adapted, as it does in its own organic structure. If an animal, for example, it has a special structure with special instincts, qualities, etc., and the external circumstances, the climate, the vegetation, all things are in perfect harmony. This law may be said to be universal, for the few seeming exceptions scarcely deserve notice. There are a few plants and cereals suited to all climates. The potato, of American origin, is cultivated with equal success in Europe, while most of our ordinary vegetables are of European origin. Wheat grows with equal luxuriance in the Valley of the Nile, the table-lands of Mexico, and the great Northwest. But while all of these things, and many more, are thus capable of successful cultivation in different localities from those in which they were originally created, the external conditions must be preserved—the same or similar soil, and, to a certain extent, the same climate or the same heat and moisture are essential in their cultivation. This is also generally true of animals. Our domestic animals are all suited to different climates. The horse, dog, ox, sheep, etc., are of European origin—some of them Asiatic—and they live and multiply with equal certainty under the fervid suns of the tropics, or amid the icy blasts of the extreme North. They are striking exceptions, however, to the general law which adapts—all creatures to their own centres of existence, and, it would seem, were designed by the Almighty and beneficent Creator for the especial purpose of benefiting man. They have accompanied him in all his wanderings, especially the dog and horse, shared his fortunes, aided in fighting his battles, and however subordinate, played an important _rôle_ in the civilization of mankind. They are closely associated in this capacity for resisting external circumstances with man himself, that is, the Caucasian, or master man, who, as regards mere climate, is capable of living and of enjoying the healthy development of all his faculties in all climates alike, unless, perhaps, the polar regions, or extreme North. As a general law, all creatures, as they ascend in the scale of being, become less and less subject to external influences; but some of our domestic animals are certainly exceptions, for the dog and horse, at all events, are capable of living where the negro, and possibly the Mongol, would surely become extinct. The same general laws of climate affect the human races, not exactly similarly, of course, but approximatively as they do animals, and with a certain modification, as they do plants—that is, they have all centres of existence to which they are _specifically_ adapted, with the sole exception of the Caucasian, as some of our domestic animals, and indeed some vegetable existences are exceptions.