The conception of Yoga as we meet it in the Maitrâya@na Upani@sad consisted of six a@ngas or accessories, namely prâ@nâyâma, pratyâhâra, dhyâna, dhara@nâ, tarka and samâdhi [Footnote ref 1]. Comparing this list with that of the list in the _Yoga sûtras_ we find that two new elements have been added, and tarka has been replaced by âsana. Now from the account of the sixty-two heresies given in the _Brahmajâla sutta_ we know that there were people who either from meditation of three degrees or through logic and reasoning had come to believe that both the external world as a whole and individual souls were eternal. From the association of this last mentioned logical school with the Samâdhi or Dhyâna school as belonging to one class of thinkers called s'âs'vatavâda, and from the inclusion of tarka as an a@nga in samâdhi, we can fairly assume that the last of the a@ngas given in Maitrâya@nî Upani@sad represents the oldest list of the Yoga doctrine, when the Sâ@mkhya and the Yoga were in a process of being grafted on each other, and when the Sa@mkhya method of discussion did not stand as a method independent of the Yoga. The substitution of âsana for tarka in the list of Patañjali shows that the Yoga had developed a method separate from the Sa@mkhya. The introduction of ahi@msâ (non-injury), satya (truthfulness), asteya (want of stealing), brahmacaryya (sex-control), aparigraha (want of greed) as yama and s'auca (purity), santo@sa (contentment) as niyama, as a system of morality without which Yoga is deemed impossible (for the first time in the sûtras), probably marks the period when the disputes between the Hindus and the Buddhists had not become so keen. The introduction of maitrî, karu@nâ, muditâ, upek@sâ is also equally significant, as we do not find them mentioned in such a prominent form in any other literature of the Hindus dealing with the subject of emancipation. Beginning from the _Âcârâ@ngasûtra, Uttarâdhyayanasûtra_, ____________________________________________________________________ [Footnote 1: _prâ@nâyâmah pratyâhârah dhyânam dhara@nâ tarkah samâdhih sa@da@nga ityucyate yoga_ (Maitr. 6 8).] 237