Aryan languages are spoken all the way from northern India to Europe’s westernmost confines. This territory comprises the western extension of the central belt of high Eurasian mountains together with its fringing lowlands. In its elevated portion it is the domain of the Alpine race and of the Nordic in its depressed northern border. On the other hand, that portion of the northern Eurasian grasslands which extends into Europe forms part of the area of Uralo-Altaic languages. It is sometimes contended that the original home of Aryan languages was situated in northern Europe, where full-blooded northerners now speak languages belonging to this family. But the weight of evidence in favor of a central European origin will seem almost decisive when we remember that culture and civilization have invariably proceeded from temperate regions. The Aryans issued at first from the contact of northern European lowlanders with the highlanders of central Europe, subsequently mingled with the inhabitants of the Mediterranean basin. As they migrated southward they must have changed continually in race. Every absorption of southern elements tended to modify their racial characteristics. A given type therefore corresponds to a definite period and place. The vagueness conveyed by the term Aryan, whether applied to language or people, is to be explained by the inherent instability of the subject. A theoretical representation of the operation of this change may be offered by assuming that NA is the offspring of the first Nordic N having come in contact with an Alpine A. The tendency for NA is to migrate southwards. His offspring may be represented as NAA as the likelihood is that NA will have taken an Alpine wife to himself. This is the prelude to a long series of generations to each of which an A strain is added. At the same time the steadily maintained migration of Nordics in a southerly direction towards and beyond the territory occupied by the Alpines tends to bring new N strains to the mixed product. At a given stage contact with Mediterranean races becomes established and the process of obliterating Nordic traits is intensified. We thus see that as the northern invaders pressed southward they became more or less absorbed in the indigenous populations. Their physique changed and their individuality vanished. However great the strength of the invaders, they could bring relatively few women in their train. This was especially true whenever they operated in a mountainous country. The passes through which their advance was made were open only to the more vigorous in the bands of fighting men or adventurers.