i. Endogamy. The Caste system is a hierarchy of endogamous groups that individuals enter only by birth. A caste differs from a clan or sib in being endogamous and recognizing various ranks. It differs from a class in its strict enforcement of permanent endogamy within caste groups. The largest enumeration of castes was in the I9oi Census which listed 2,378 main castes and (No. I, 537, 557) some of which in turn are divided into endogamous subcastes of which the Brahmans are said to have 8cc. All ancient occupations used to be organized on a caste basis, even those now considered anti-social. The Census speaks of 4,500,000 persons belonging to castes and tribes whose hereditary occupation is crime of one kind or another-theft, burglary, highway robbery, or even assassination, combined in many instances with prostitution. 2. Compelling religious sanctions. The caste system of India differs from the class systems of other countries mainly in being invested with the mighty sanctions of the ancient Hindu religion, as is evidenced by the very name given to the system, varna ashrama dharma. Varna means color, ashrama may be translated religious discipline, while dharma covers religio-social righteousness, obligations and mores. The families of a caste often have a common name and occupation. To be a good Hindu a man may believe anything or nothing but he must fulfill his caste obligations. Orthodox Hinduism prohibits him from marrying his child to a person of another caste, from eating and drinking with an outsider, from eating unfit or unclean food, from touching an Outcaste or letting his shadow fall upon him, and from following an unsuitable occupation. A villager's failure to observe minutely all the taboos and elaborate ceremonial rules usually leads to his being boycotted by his fellow caste-men as to marriage and food, and sometimes as to companionship, drink and tobacco. Even the village artisans will not deign to serve him. Until a few decades ago no strict Hindu might cross the black waters of the ocean with impunity. To be received back into caste he had to make atonement by swallowing a pellet of the five products of the sacred cow, including the dung and urine. In the authoritative Bhagavadgita, when Arjuna hesitates to slay his distant relatives, his divine charioteer Lord Krishna reminds him that he is a Kshatriya (warrior) and that he must never swerve from his caste diarma: