At a subsequent period the demand for instruction in the sacrificial science called into existence a still more practical set of manuals, the so-called Kalpa-sutras, or ceremonial rules, detailing, in succinct aphorisms, the approved course of sacrificial procedure, without reference to the supposed origin or import of the several rites.
It is, however, to the Brahmanas and Sutras of the Yajurveda, dealing with the ritual of the real offering-priest, the Adhvaryu, that we have to turn for a connected view of the sacrificial procedure in all its material details.
An even more complete and minutely detailed view of the sacrificial system is no doubt obtained from the ceremonial manuals, the Kalpa-sutras; but it is just by the speculative discussions of the Brahmanasthe mystic significance and symbolical colouring with which they invest single rites - that we gain a real insight into the nature and gradual development of this truly stupendous system of ritual worship.
(a) The division into periodical and occasional is important in Hindu and other higher religions, and the sutras constantly draw the distinction; the former class is obligatory, the latter facultative.
So great were his learning and piety that he was regarded as an incarnation of Siva, and his works (commentaries on the Vedanta Sutras, the Bhagavad Gita and the Upanishads) exercised a permanent influence on Hindu thought.