The three first castes, however unequal to each other in privilege and social standing, are yet united by a common bond of sacramental rites (_samskaras_), traditionally connected from ancient times with certain incidents and stages in the life of the Aryan Hindu, as conception, birth, name-giving, the first taking out of the child to see the sun, the first feeding with boiled rice, the rites of tonsure and hair-cutting, the youth's investiture with the sacrificial thread, and his return home on completing his studies, marriage, funeral, &c. The modes of observing these family rites are laid down in a class of writings called _Grihya-sutras_, or domestic rules. The most important of these observances is the _upanayana_, or rite of conducting the boy to a spiritual teacher. Connected with this act is the investiture with the sacred cord, ordinarily worn over the left shoulder and under the right arm, and varying in material according to the class of the wearer. This ceremony being the preliminary act to the youth's initiation into the study of the Veda, the management of the consecrated fire and the knowledge of the rites of purification, including the _savitri_, a solemn invocation to _Savitri_, the sun (probl. Saturnus),--as a rule the verse _Rigv_. iii. 62. 10, also called _gayatri_ from the metre in which it is composed--which has to be repeated every morning and evening before the rise and after the setting of that luminary, is supposed to constitute the second or spiritual birth of the Arya. It is from their participation in this rite that the three upper classes are called the twice-born. The ceremony is enjoined to take place some time between the eighth and sixteenth year of age in the case of a Brahman, between the eleventh and twenty-second year of a Kshatriya, and between the twelfth and twenty-fourth year of a Vaisya. He who has not been invested with the mark of his class within this time is for ever excluded from uttering the sacred _savitri_ and becomes an outcast, unless he is absolved from his sin by a council of Brahmans, and after due performance of a purificatory rite resumes the badge of his caste. With one not duly initiated no righteous man is allowed to associate or to enter into connexions of affinity. The duty of the Sudra is to serve the twice-born classes, and above all the Brahmans. He is excluded from all sacred knowledge, and if he performs sacrificial ceremonies he must do so without using holy mantras. No Brahman must recite a Vedic text where a man of the servile caste might overhear him, nor must he even teach him the laws of expiating sin. The occupations of the Vaisya are those connected with trade, the cultivation of the land and the breeding of cattle; while those of a Kshatriya consist in ruling and defending the people, administering justice, and the duties of the military profession generally. Both share with the Brahman the privilege of reading the Veda, but only so far as it is taught and explained to them by their spiritual preceptor. To the Brahman belongs the right of teaching and expounding the sacred texts, and also that of interpreting and determining the law and the rules of caste. Only in exceptional cases, when no teacher of the sacerdotal class is within reach, the twice-born youth, rather than forego spiritual instruction altogether, may reside in the house of a non-Brahmanical preceptor; but it is specially enjoined that a pupil, who seeks the path to heaven, should not fail, as soon as circumstances permit, to resort to a Brahman well versed in the Vedas and their appendages.