The question presents very different aspects according as we confine ourselves to the present or take into consideration the geological antiquity of man. Nevertheless, the facts are of the same order and seem to indicate two extremes. The truth lies, perhaps, between the two. We know that in Asia there is a vast region bounded on the south and south-west by the Himalayas, on the west by the Bolor mountains, on the north-west by the Ala-Tau, on the north by the Altai range and its offshoots, on the east by the Kingkhan, on the south and south-east by the Felina and Kuen-Loun. Judging from the present state of things, this great central region might be regarded as having contained the cradle of the human species. In fact, the three fundamental types of all the human races are represented in the populations grouped round this region. The black races are the furthest removed from it, but have, nevertheless, marine stations, where we find them either pure or as mixed races, from the Kioussiou to the Andaman Islands. Upon the continent they have intermixed with almost every inferior caste and class of the two peninsulas of the Ganges; they are still found pure in both, ascend as high as Nepaul, and extend west as far as the Persian Gulf and Lake Zareh, according to Elphinstone. The yellow race, either pure or in places mixed with white elements, seems to be the only one which occupies the space in question; it peoples all the north, east, south-east, and west. In the south it is more mixed, but forms, nevertheless, an important element in the population. The white race, from its allophylian representatives, seems to have disputed the central area itself with the yellow race. In early times, we find the Yu-tchi and the Ou-soun to the north of the Hoang-ho; and in the present day cases of white populations have been observed in Little Thibet and in Eastern Thibet. The Miao-Tsé occupy the mountain region of China; the Siaputh are proof against all attack in the gorges of the Bolor. Upon the confines of the area we meet with the Aïnos and the Japanese of high caste, the Tinguianes of the Phillippine Islands; in the south with the Hindoos. In the south-west and west the white element, either pure or mixed, reigns supreme. No other region of the globe presents a similar union of extreme human types distributed round a common centre. This fact, alone is sufficient to suggest to the mind of the naturalist the conjecture which I have expressed above; but we may appeal to other considerations.