ferring supernatural powers, it here becomes the chief means of salvation. His Sūtras consist of four chapters dealing with deep meditation (samādhi), the means for obtaining it (sādhana), the miraculous powers (vibhūti) it confers, and the isolation (kaivalya) of the redeemed soul. The oldest and best commentary on this work is that of Vyāsa, dating from the seventh century A.D.
Many of the later Upanishads are largely concerned with the Yoga doctrine. The lawbook of Manu in Book VI. refers to various details of Yoga practice. Indeed, it seems likely, owing to the theistic point of view of that work, that its Sānkhya notions were derived from the Yoga system. The Mahābhārata treats of Yoga in considerable detail, especially in Book XII. It is particularly prominent in the Bhagavadgītā, which is even designated a yoga-çāstra. Belief in the efficacy of Yoga still prevails in India, and its practice survives. But its adherents, the Yogīs, are at the present day often nothing more than conjurers and jugglers.
The exercises of mental concentration are in the later commentaries distinguished by the name of rāja-yoga or "chief Yoga." The external expedients are called kriyā-yoga, or "practical Yoga." The more intense form of the latter, in later works called haṭha-yoga, or "forcible Yoga," and dealing for the most part with suppression of the breath, is very often contrasted with rāja-yoga.
Among the eight branches of Yoga practice the sitting posture (āsana), 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 haṭha-yoga there
