In the East, the middle stage of barbarism began with the taming of milk and meat producing animals, while the cultivation of plants seems to have remained unknown far into this period. It appears that the taming and raising of animals and the formation of large herds gave rise to the separation of Aryans and Semites from the rest of the barbarians. Names of animals are still common to the languages of European and Asian Aryans, while this is almost never the case with the names of cultivated plants.
In suitable localities, the formation of herds led to a nomadic life, as with the Semites in the grassy plains of the Euphrates and Tigris, the Aryans in the plains of India, of the Oxus, Jaxartes, Don and Dnieper. Along the borders of such pasture lands, the taming of animals must have been accomplished first. But later generations conceived the mistaken idea that the nomadic tribes had their origin in regions supposed to be the cradle of humanity, while in reality their savage ancestors and even people in the lower stage of barbarism would have found these regions almost unfit for habitation. On the other hand, once these barbarians of the middle stage were accustomed to nomadic life, nothing could have induced them to return voluntarily from the grassy river plains to the forests that had been the home of their ancestors. Even when Semites and Aryans were forced further to the North and West, it was impossible for them to occupy the forest regions of Western Asia and Europe, until they were enabled by agriculture to feed their animals on this less favorable soil and especially to maintain them during the winter. It is more than probable that the cultivation of grain was due primarily to the demand for stock feed, and became an important factor of human sustenance at a later period.
The superior development of Aryans and Semites is, perhaps, attributable to the copious meat and milk diet of both races, more especially to the favorable influence of such food on the growth of children. As a matter of fact, the Pueblo Indians of New Mexico who live on an almost purely vegetarian diet, have a smaller brain than the Indians