The affix śa (a) is used after the roots pā 'to drink', ghrā 'to smell', dhmā 'to blow' and dheṭ 'to suck' and dṛś 'to see' when there is a preposition along with these roots.,
Thus उत् + पा + शा = उत् + पिब् + अ 7.3.78 = उत्पिब nom. sing. उत्पिबः; so also विपिबः; उज्जिघ्रः and विजिघ्रः । उत् + ध्मा + श = उत् + धम्+ अ = 7.3.78; उद्धमः; विधमः; उत् + धे + श = उद्धयः; विधयः; so also उत् + दृश् + शा = उत्पश्यः, 7.3.78. so also विपश्यः;
Some commentators do not read the word 'upasarga' into this sutra. According to them the forms like पश्यः &c., can be formed also.
The affix श, of which श् is indicatory, the real affix being अ, causes the root to undergo all those changes, which it undergoes in special tenses; for it is a sarvadhatuka affix there; see sutra 3.4.113 and 7.3.78.
Vart:- Prohibition must be stated of the root घ्रा, when the word to be formed is a name. As वि + आ + घ्रा + क = व्याघ्रः 'tiger' (an animal that goes about smelling). Here there is क and not the affix श.,