adays extremely complex. Looking from above downward, it is consequently difficult to define the lines of ethnic division with any accuracy. The analytical method furnishes sufficient distinctions, however, to establish a general classification of humanity. Taking the shape of the skull, the texture of the hair, the pigment of the skin and general structural characters into account, ethnographers have concluded that there are four elementary divisions of mankind, known particularly as the Negro or Black race, the Mongolic or Yellow race, the Caucasic or White race and the American or Red race.
Looking from below upward, it is out of the question, of course, to follow the lines of racial ramification chronologically. But though the time factor fails for the most part, the place element can usually be determined with considerable accuracy. Ethnic consequents can, accordingly, be connected in each instance with their geographic antecedents, and the outcome of the interaction between variability and environment set forth in some detail. Thus though it is out of the question to establish the chronological sequence exactly, by supplementing the analytical with the geographical method of enquiry, it should at least be possible to indicate the general order of racial ramification and determine under what environmental conditions the ethnic differentiation of mankind took place.
Corresponding to the fourfold ethnic division of the human race, there are four more or less distinctly defined geographic sections of the globe. Three of these racial regions radiate from Indo-Malaysia, the cradle-land of mankind; the fourth is situated on the opposite side of the earth, though connected in the far north with the continental area of the eastern hemisphere. Considering the situation somewhat more in detail, the four habitats may be defined as follows: Toward the south, the Indo-Malaysian abode borders upon what we may call the 'eastern-equatorial section,' which stretches out between the tropics from the west coast of Africa, across the partially submerged Indo-African continent, to Melanesia and Australia. This intertropical belt has from time immemorial been the abode of the Negro or Black race. North of the Indo-Malaysian cradle-land lies the vast 'Asiatic section' of the eastern hemisphere, which is separated from the southern peninsulas by the Himalayan line, except along the Pacific coast where passage to the north is possible between the longitudinal ranges of Cochin-China. This continental area is the traditional abode of the Mongols or Yellow people. Between the equatorial belt and the Asiatic area, the 'Indo-Mediterranean-European section' spreads out towards the west from Indo-Malaysia to the Atlantic coast of the continent. This peninsular portion of the eastern hemisphere is the historical home of the White man, the field for the development of what we are in the habit of calling Caucasian civiliza-
