From the intensely crabbed and unintelligible nature of their style, and the studied baldness with which they present their subjects, it is evident that the Sutras are inferior even to the Brahmanas as literary productions. Judged, however, with regard to its matter, this strange phase of literature has considerable value. In all other ancient literatures knowledge of sacrificial rites can only be gained by collecting stray references. But in the ritual Sutras we possess the ancient manuals which the priests used as the foundation of their sacrificial lore. Their statements are so systematic and detailed that it is possible to reconstruct from them various sacrifices without having seen them performed. They are thus of great importance for the history of religious institutions. But the Sutras have a further value. For, as the life of the Hindu, more than that of any other nation, was, even in the Vedic age, surrounded with a network of religious forms, both in its daily course and in its more important divisions, the domestic ritual as well as the legal Sutras are our most important sources for the study of the social conditions of ancient India. They are the oldest Indian records of all that is included under custom. Besides these ritual and legal compendia, the Sutra period produced several classes of works composed in this style, which, though not religious in character, had a religious origin. They arose from the study of the Vedas, which was prompted by the increasing difficulty of understanding the hymns, and of reciting them correctly, in consequence of the changes undergone by the language. Their chief object was to ensure the right recitation and interpretation of the sacred text. One of the most important classes of this ancillary literature comprises the Pratiçakhya Sutras, which, dealing with accentuation, pronunciation, metre, and other matters, are chiefly concerned with the phonetic changes undergone by Vedic words when combined in a sentence. They contain a number of minute observations, such as have only been made over again by the phoneticians of the present day in Europe. A still more important branch of this subsidiary literature is grammar, in which the results attained by the Indians in the systematic analysis of language surpass those arrived at by any other nation. Little has been preserved of the earliest attempts in this direction, for all that had been previously done was superseded by the great Sutra work of Panini. Though belonging probably to the middle of the Sutra period, Panini must be regarded as the starting-point of the Sanskrit age, the literature of which is almost entirely dominated by the linguistic standard stereotyped by him.