Asia’s size and central location to the other continents were formerly taken as an argument for its correspondingly significant position in the creation and history of man.  Its central location is reflected in the hypothesis of the Asiatic origin of the Indo-European linguistic group of peoples; and though the theory has been justly called into question, these peoples have undoubtedly been subjected to Asiatic influences.  The same thing is true of the native American race, both as to Asiatic origin and influences; because the approximation of Siberia to Alaska is too close to exclude human relations between the two continents.  The Malays, too, were probably sprung from the soil of southeastern Asia and spread thence over their close-packed Archipelago.  Even the native Australians betray a Malayan and therefore Asiatic element in their composition,[749] while the same element can be traced yet more distinctly in the widely scattered Polynesians and the Hovas of Madagascar.  This radiation of races seems to reflect Asia’s location at the core of the land-masses.  Yet the capacity to form such centers of ethnic distribution is not necessarily limited to the largest continents; history teaches us that small areas which have early achieved a relatively dense population are prone to scatter far their seeds of nations.

[Sidenote:  Location of hemispheres and ethnic kinship.]

The continents harbor the most widely different races where they are farthest apart; where they converge most nearly, they show the closest ethnic kinships.  The same principle becomes apparent in their plants and animals.  The distribution of the land-masses over the earth is conspicuous for their convergence in the north and divergence in long peninsular forms toward the south.  The contrasted grouping is reflected in both, the lower animals and the peoples inhabiting these respectively vicinal and remote lands.  Only where North America and Eurasia stretch out arms to one another around the polar sea do Eastern and Western Hemisphere show a community of mammalian forms.  These are all strictly Arctic animals, such as the reindeer, elk, Arctic fox, glutton and ermine.[750] This is the Boreal sub-region of the Holoarctic zoological realm, characterized by a very homogeneous and very limited fauna.[751] In contrast, the portion of the hemispheres lying south of the Tropic of Cancer is divided into four distinct zoological realms, corresponding to Central and South America, Africa south of Sahara, the two Indian peninsulas with the adjacent islands, and Australia.[752] But when we consider the continental extremities projecting beyond the Tropic of Capricorn, where geographic divergence reaches a climax, we find their faunas and floras utterly dissimilar, despite the fact that climate and physical conditions are very similar.[753] We find also widely divergent races in the southern sections of Africa, Australia or Tasmania and South America, while Arctic Eurasia and America