Note 301 — Chapter VI · —Geographical Area

If the distribution of the several races be examined in the light of this conclusion, it becomes apparent that the races who have succeeded in appropriating only limited portions of the earth's surface, though each may be a marked variant of the human family, are characterized by few inner diversities, either of physical features or culture. Their subdivisions feel only in a slight degree the differentiating effects of geographic remoteness, which in a small area operates with weakened force; and they enjoy few of those diversities of environment which stimulate variation. They form close and distinct ethnic unities also because their scant numbers restrict the appearance of variations. The habitat of the negro race in Africa south of the Sahara, relatively small, limited in its zonal location almost wholly to the Tropics, poorly diversified both in relief and contour, has produced only a retarded and monotonous social development based upon tropical agriculture or a low type of pastoral life. The still smaller, still less varied habitat of the Australian race, again tropical or sub-tropical in location, has produced over its whole extent only one grade of civilization and that the lowest, one physical, mental and moral type.301