“The expeditions of the great hordes of nomads contrast with this movement, drop by drop and step by step, since they overflow with tremendous power, especially Central Asia and all neighboring countries. The nomads of this district, as of Arabia and Northern Africa, unite mobility in their way of life with an organization holding together their entire mass for one single object. It seems to be a characteristic of the nomads that they easily develop despotic power and far-reaching might from the patriarchal cohesion of the tribe. Mass governments thereby come into being, which compare with other movements among men in the same way that swollen streams compare with the steady but diffused flow of a tributary. The history of China, India, and Persia, no less than that of Europe, shows their historical importance. Just as they moved about on their ranges with their wives and children, slaves and carts, herds and all their paraphernalia, so they inundated the borderlands. While this ballast may have deprived them of speed it increased their momentum. The frightened inhabitants were driven before them, and like a wave they rolled over the conquered countries, absorbing their wealth. Since they carried everything with them, their new abodes were equipped with all their possessions, and thus their final settlements were of an ethnographic importance. After this manner, the Magyars flooded Hungary, the Manchus invaded China, the Turks, the countries from Persia to the Adriatic.”[28]
What has been said here of Hamites, Semites and Mongolians, may be said also, at least in part, of the Arian tribes of herdsmen. It applies also to the true negroes, at least to those who live entirely from their herds: “The mobile, warlike tribes of the Kafirs possess a power of expansion which needs only an enticing object in order to attain violent effects and to overturn the ethnologic relations of vast districts. Eastern Africa offers such an object. Here the climate did not forbid stock raising, as in the countries of the interior, and did not paralyze from the start, the power of impact of the nomads, while nevertheless numerous peaceable agricultural peoples found room for their development. Wandering tribes of Kafirs poured like devastating streams into the fruitful lands of the Zambesi, and up to the highlands between the Tanganyika and the coast. Here they met the advance guard of the Watusi, a wave of Hamite eruption, coming from the north. The former inhabitants of these districts were either exterminated, or as serfs cultivated the lands which they formerly owned; or they still continued to fight; or again, they remained undisturbed in settlements left on one side by the stream of conquest.”[29]