Of the different standards of morality of the several castes that of the Brahman is of course the highest. The study of the sacred books is for him the chief duty. “Let him,” says the sacred law, “without tiring daily mutter the Veda at the proper time; for that is one’s highest duty; all other observances are secondary duties.”[248] Knowledge of the Veda destroys guilt as fire consumes fuel.[249] Among the secondary duties are observance of the rules of purification, the practice of austerities, and doing no injury to created beings.[250] By austerities, that is, by ascetic practices, by hideous self-torture, the Brahman may atone for all sins of whatsoever kind and may become so holy that at death, having conquered all desires, save only the desire for union with the Universal One, he may hope to fall away into unawakening unconsciousness and be absorbed into the absolute, impersonal Brahma, and thus escape forever from the weary round of births. This way of full salvation, and it is the only one, is open only to Brahmans and to the chosen few from other castes who, having gone forth “from home into homelessness,” as mendicants or forest hermits, follow this life of complete renunciation of all that is earthly. [Sidenote: The moral code for inferior castes] The duties, the faithful performance of which avail most for persons of inferior castes, are those that have to do with religion, and chiefly with sacrifice. These duties are the bringing of gifts and offerings for the sacrifices and the giving of generous fees to the priests. Through the faithful performance of his assigned duties the man of inferior caste can make sure of salvation--not the full and perfect salvation attained by the Brahman through his austerities, but a qualified salvation. He may hope for rebirth in some higher caste or in some better state either on earth or in some other world.[251] [Sidenote: Animal ethics] Duty to animals seems to have formed no part of the moral code of the early Indian Aryans. But chiefly through the influence of the doctrine of transmigration respect for every living thing became a high moral requirement. To take life wantonly became a crime. To kill a kine, a horse, a camel, a deer, an elephant, a goat, a sheep, a fish, a snake, a buffalo, insects, or birds is an offense which must be expiated by penances.[252] In order that he may not harm any living creature, the ascetic is enjoined “always by day and by night, even with pain to his body, to walk carefully, scanning the ground.”[253] Should he unintentionally injure any creature he must expiate its death by penitent austerities.[254] Animals may, however, be slain for food[255] and for sacrifices, since they were created for these special purposes. And then there is compensation for the victims of the altars: “Herbs, trees, cattle, birds, and all animals that have been destroyed for sacrifices receive, being reborn, higher existences.”[256]