183. The nasalization of the alterant vowel — or, in other words, its being followed by anusvāra — does not prevent its altering effect upon the sibilant: thus, havīṅṣi, parūṅṣi. And the alteration takes place in the initial s of an ending after the final s of a stem, whether the latter be regarded as also changed to ṣ or as converted into visarga: thus, haviṣṣu or haviḥṣu, paruṣṣu or paruḥṣu.
a. But the s of puṁs (394) remains unchanged, apparently on account of the retained sense of its value as pums; also that of √hiṅs, because of its value as hins (hinasti etc.); √niṅs (RV. only) is more questionable.
184. The principal cases of alteration of s in internal combination are these:
a. In endings, inflectional or derivative, beginning with s — thus, su; si, se, sva; s of sibilant-aorist, future, and desiderative; suffixes sna, snu, sya, etc. — after a final alterant vowel or consonant of root or stem, or a union-vowel: thus, juhoṣi, çeṣe, anāiṣam, bhaviṣyāmi, çuçrūṣe, deṣṇa, jiṣṇu, vikṣu, akārṣam.
b. The final s of a stem before an ending or suffix: thus: haviṣā, haviṣas, etc., from havis; çakṣuṣmant, çociṣka, mānuṣa, manuṣya, jyotiṣṭva.
c. Roots having a final sibilant (except ç) after an alterant vowel are — with the exception of fictitious ones and pis, niṅs, hiṅs — regarded as ending in ṣ, not s; and concerning the treatment of this ṣ in combination, see below, 225–6.
d. The initial s of a root after a reduplication: thus, siṣyade, suṣvāpa, siṣāsati, coṣkūyate, saniṣvaṇat.
e. Excepted is in general an initial radical s in a desiderative stem, when the desiderative-sign becomes ṣ: thus, sisīrṣati from √sṛ, sisan̄kṣati from √sañj. And there are other scattering cases, as tresus (perf. from √tras), etc.
185. But the same change occurs also, on a considerable scale, in external combination, especially in composition. Thus:
a. Both in verbal forms and in derivatives, the final i or u of a preposition or other like prefix ordinarily lingualizes the initial s of the root to which it is prefixed; since such combinations are both of great frequency and of peculiar intimacy, analogous with those of root or stem and affix: thus, abhiṣā́c, pratiṣṭhā́, níṣikta, víṣita; anuṣvadhám, suṣéka; the cases are numberless.
b. The principal exceptions are in accordance with the principles already laid down: namely, when the root contains an r-element, and when a recurrence of the sibilant would take place. But there are also others, of a more irregular character; and the complete account of the treatment of initial radical s after a prefix would be matter of great detail, and not worth giving here.
