Among the eight branches of Yoga practice the sitting posture (asana), as not only conducive to concentration, but of therapeutic value, is considered important. In describing its various forms later writers positively revelled, eighty-four being frequently stated to be their normal number. In the hatha-yoga there are also a number of other postures and contortions of the limbs designated mudra. The best-known mudra, called khechari, consists in turning the tongue back towards the throat and keeping the gaze fixed on a point between the eyebrows. Such practices, in conjunction with the suppression of breath, were capable of producing a condition of trance. There is at least the one well-authenticated case of a Yogi named Haridas who in the thirties wandered about in Rajputana and Lahore, allowing himself to be buried for money when in the cataleptic condition. The burial of the Master of Ballantrae by the Indian Secundra Dass in Stevenson's novel was doubtless suggested by an account of this ascetic. In contrast with the two older and intimately connected dualistic schools of the Sankhya and Yoga, there arose about the beginning of our era the only two, even of the six orthodox systems of philosophy, which were theistic from the outset. One of them, being based on the Vedas and the Brahmanas, is concerned with the practical side of Vedic religion; while the other, alone among the philosophical systems, represents a methodical development of the fundamental non-dualistic speculations of the Upanishads. The former, which has only been accounted a philosophical system at all because of its close connection with the latter, is the Purva-mimamsa or "First Inquiry," also called Karma-mimamsa or "Inquiry concerning Works," but usually simply Mimamsa. Founded by Jaimini, and set forth in the Karma-mimamsa Sutras, this system discusses the sacred ceremonies and the rewards resulting from their performance. Holding the Veda to be uncreated and existent from all eternity, it lays special stress on the proposition that articulate sounds are eternal, and on the consequent doctrine that the connection of a word with its sense is not due to convention, but is by nature inherent in the word itself. Owing to its lack of philosophical interest, this system has not as yet much occupied the attention of European scholars. The oldest commentary in existence on the Mimamsa Sutras is the bhashya of Çabara Svamin, which in its turn was commented on about 700 A.D. by the great Mimamsist Kumarila in his Tantra-varttika and in his Çloka-varttika, the latter a metrical paraphrase of Çabara's exposition of the first aphorism of Patanjali. Among the later commentaries on the Mimamsa Sutras the most important is the Jaiminiya-nyaya-mala-vistara of Madhava (fourteenth century).