to the carrying out of their religious duties and the handing down of the sacred tradition in their families.
Owing to these causes, the three main classes of Aryan society became more and more separated. But how were they transformed into castes or social strata divided from one another by the impassable barriers of heredity and the prohibition of intermarrying or eating together? This rigid mutual exclusiveness must have started, in the first instance, from the treatment of the conquered aborigines, who, on accepting the Aryan belief, were suffered to form a part of the Aryan polity in the capacity of a servile class. The gulf between the two races need not have been wider than that which at the present day, in the United States, divides the whites from the negroes. When the latter are described as men of "colour," the identical term is used which, in India, came to mean "caste." Having become hereditary, the sacerdotal class succeeded in securing a position of sanctity and inviolability which raised them above the rest of the Aryans as the latter were raised above the Dāsas. When their supremacy was established, they proceeded to organise the remaining classes in the state on similar lines of exclusiveness. To the time when the system of the three Aryan castes, with the Çūdras added as a fourth, already existed in its fundamental principles, belong the greater part of the independent portions of the Yajurveda, a considerable part of the Atharva-veda (most of books viii. to xiii.), but of the Rigveda, besides the one (x. 90) which distinctly refers to the four castes by name, only a few of the latest hymns of the first, eighth, and tenth books. The word brāhmaṇa, the regular name for "man of the first caste," is still rare in the Rigveda, occurring only eight times, while brahman,
