by stern inhibition of intermarriage with other tribes.
Therefore, Moses enjoined upon them the duty of exterminating the
peoples of Canaan whom they dispossessed.[1176] While the urban Arabs
show a medley of breeds, dashed with a strain of negro blood, among the
nomad Bedouins, mixture is exceptional and is regarded as a
disgrace.[1177] The same thing is true among the nomad Arabs of Algeria,
and there it has placed a stumbling block in the way of the French
colonial administration, by preventing the appearance of half-breeds who
might bridge the gap between the colonials and natives. Where pastoral
Semites have settled in agricultural lands, intermixture on a wide scale
has followed, as in the Sudan from Niger to Nile; but even here, when a
tribe or clan has retained a strictly pastoral life in the grassland,
and has held itself aloof from the agricultural districts of the Negro
villages, relatively pure survivals are to be found, as among the Cow
or Bush Fulani of Bornu.[1178] On the other hand, the Hausa, a migrant
trading folk of mingled Arab and Negro blood, spread northward along the
trans-Saharan caravan route to the oasis of Air before the fourteenth
century, and there have infused into the local Berber stock a strong
Negro strain.[1179] Among the nomads of Central Asia, one wave of race
movement has so often followed and overtaken another, that it has
produced a confused blending of breeds. The mixtures are so numerous
that pure types are exceptional,[1180] and the exclusiveness of the
desert Semites disappears.

[Sidenote: Religion of pastoral nomads.]

Though all these desert-born characteristics and customs have a certain
interest for the sociologist, they possess only minor importance in
comparison with the religious spirit of pastoral nomads, which is always
fraught with far-reaching historical results. The evidence of history
shows us that there is such a thing as a desert-born genius for
religion. Huc and Gabin testify to the deeper religious feeling of the
Buddhist nomads of the Central Asia plateaus, as compared with the
lowland Chinese. The three great monotheistic religions of the world are
closely connected in their origin and development with the deserts of
Syria and Arabia. The area of Mohammedism embraces the steppe zone of
the Old World[1181] from Senegambia and Zanzibar in Africa to the Indus,
Tarim and the upper Obi, together with some well watered lands on its
margins. It comprises in this