THE VERB 295 distinction between active and passive, and the use of the middle to express a passive sense becomes common in the perfect and the future, which possess no other means of expressing the passive. One sense that the middle does not normally express is that of a direct reflexive, which is expressed by means of the accusative dtmdnam ' self Not all verbs are capable of appear- ing in both voices. Some are used only in the active, e.g. ad- ' to eat as- ‘ to be ksudh- ' to be hungry 7 bhuj- ‘ to bend sarp - 9 to creep ', etc, ; others only in the middle, e.g., as- ‘ to sit hsam - * to endure labh- 4 to receive ’, vas- 4 to wear (clothes) sac- f to accompany Occasionally a different voice appears in different tenses of the same verb, the most usual alternation being that of active perfect and middle present : vartate : vavarta. The distinction between active and middle is inherited from Indo-European (cf, the equation sdcate , Gk. e^rat, Lat. sequitur ), and outside Indo-Iranian the language which shows the greatest similarity to Sanskrit in form and usage is Greek. In later Indo-Aryan the distinction dies out, and this is re- flected in the Epic and other less correct forms of Sanskrit. Tense . The Sanskrit verb has four tense stems : Present, Future, Aorist and Perfect. The present stem forms the basis of a preterite, the so-called Imperfect, in addition to the present tense. In the same way there is formed a preterite of the future which functions as a conditional. In the Vedic language a form of preterite is formed on the basis of the perfect stem. These pluperfect forms are rare even in the earlier language, and dis- appear later. The aorist stem forms only a preterite. The clearest division to be found in this somewhat compli- cated system is that between the perfect on the one hand and the other three systems on the other. The perfect is distin- guished from the other tenses not only in stem-formation, but also in the fact that it possesses a special series of personal endings. Between the perfect and the rest of the conjugation we have clearly the most ancient and fundamental division in the Indo-European system. On the other hand when we examine the future and the aorist in their relation to the present system it is clear that they are in origin only special modifica- tions of the same type of formation. The future for instance is only one subdivision of the class of present stems in ya in which are included the verbs of the foprth class and the various types
