81:3.1

The climatic destruction of the rich, open grassland hunting and grazing grounds of Turkestan, beginning about 12,000 b.c., compelled the men of those regions to resort to new forms of industry and crude manufacturing. Some turned to the cultivation of domesticated flocks, others became agriculturists or collectors of water-borne food, but the higher type of Andite intellects chose to engage in trade and manufacture. It even became the custom for entire tribes to dedicate themselves to the development of a single industry. From the valley of the Nile to the Hindu Kush and from the Ganges to the Yellow River, the chief business of the superior tribes became the cultivation of the soil, with commerce as a side line.