225. Since the lingual sibilant

The lingual sibilant ष् ṣ.

Since the lingual sibilant, in its usual and normal occurrences, is (182) the product of lingualization of s after certain alterant sounds, we might expect final radical ṣ, when (in rare cases) it comes to stand where a ṣ cannot maintain itself, to revert to its original, and be treated as a s would be treated under the same circumstances. That, however, is true only in a very few instances.

a. Namely, in the prefix dus (evidently identical with √duṣ); in sajū́s (adverbially used case-form from √juṣ); in (RV.) vivés and ávives, from √viṣ; in āíyes (RV.), from √īṣ; and in āçís, from çiṣ as secondary form of √çās. All these, except the first two, are more or less open in question.