c. Before iṣa, a final i- or u- or ṛ-vowel necessarily, and a penultimate i or u or ṛ optionally, have the guṇa-strengthening; no examples are quotable from the older texts; later occur çiçayiṣa, çiçariṣa; cikartiṣa, ninartiṣa, mimardiṣa, vivarṣiṣa, çuçobhiṣa; but rurudiṣa.
More special exceptions are:
d. A few roots in ā weaken this vowel to ī or even i: thus, jigīṣa from √gā go; pipīṣa (beside pipāsa) from √pā drink, jihīṣa (AV.) from √hā remove (jihīte: 664); didhiṣa (beside dhitsa) from √dhā.
e. A few roots in an or am lengthen the vowel: thus, jigāṅsa (beside jigamiṣa) from √gam; jighāṅsa from √han; mīmāṅsa from √man; and titāṅsa from √tan.
f. Reversion to guttural form of an initial after the reduplication is seen in cikīṣa from √ci, cikitsa from √cit, jigīṣa from √ji, jighāṅsa from √han; and √hi is said to make jighīṣa (no occurrence).
g. The roots van and san make vivāsa and siṣāsa, from the root-forms vā and sā.
h. The root jīv forms jujyūṣa (ÇB.: jijīviṣa, VS.); and the other roots in īv (765) are required to make the same change before sa, and to have guṇa before iṣa: thus, susyūṣa or siseviṣa from √sīv. Svap forms suṣupsa. Dhūrv forms dudhūrṣa.
i. Initial s is usually left unchanged to ṣ after the reduplication when the desiderative sign has ṣ (184 e): thus, sisan̄kṣa (ÇB.: √sañj), and susyūṣa and sisaniṣa, according to the grammarians; but tuṣṭūṣa is met with.
j. Further may be mentioned as prescribed by the grammarians: ninan̄kṣa (or ninaçiṣa) from √nāç be lost; miman̄kṣa from √majj (occurs in miman̄kṣu); mimārjiṣa (or mimṛkṣa) from √mṛj.
1029. The consonant of the reduplication follows the general rules (590); the vowel is इ i if the root has an a-vowel, or ऋ ṛ, or an i-vowel; it is उ u if the root has an u-vowel. But:
a. A few roots have a long vowel in the reduplicating syllable: thus, bībhatsa from √badh or bādh; mīmāṅsa from √man; and tūtūrṣa (RV.) from √tur; dadhiṣu (AV.) and dadan̄kṣu (C.) are probably false forms.
b. From √aç is made (ÇB.) açiçiṣa, and from √edh (VS.) edidhiṣa (with a mode of reduplication like that followed sometimes in the reduplicating aorist: 862). In the older language, these are the only roots with initial vowel which form a desiderative stem, except āp and ṛdh, which have abbreviated stems: see the next paragraph. In the later language occur further eṣiṣiṣa (√iṣ seek) and īcikṣiṣa (√īkṣ); and the grammarians add others, as arjihiṣa (√arh), undidiṣa (√und), ardidhiṣa (√ṛdh).
