Page:Sanskrit Grammar by Whitney p1.djvu/342

 877. We have, then, the following classification for the varieties of sibilant-aorist:

A. With endings added directly to the sibilant:

4. with स् simply after the root: -aorist;

5. with इ before the स् : -aorist;

6. the same, with स् at end of root: -aorist.

B. With अ added to the sibilant before the endings:

7. with sibilant and अ : -aorist.

a. As regards the distinction between the fourth and fifth forms, it may be said in a general way that those roots incline to take the auxiliary in the aorist which take it also in other formations; but it is impossible to lay down any strict rules as to this accordance. Compare 903.

878. The tense-stem of this aorist is made by adding स् to the augmented root, of which also the vowel is usually strengthened.

879. The general rules as to the strengthening of the root-vowel are these:

a. A final vowel (including ऋ ) has the -change in the active, and (excepting ऋ ) in the middle: thus, from √नी lead, active stem अनैष्, middle stem अनेष् ; from √श्रु  hear, अश्रौष्  and अश्रोष् ; from √कृ  make, अकार्ष्  and अकृष्.

b. A medial vowel has the -change in the active, and remains unaltered in the middle: thus, from √छन्द् seem, active stem अच्छान्त्स्, middle stem अच्छन्त्स् ; from √रिच्  leave, अरैक्ष्  and अरिक्ष् ; from √रुध्  obstruct, अरौत्स्  and अरुत्स् ; from √सृज्  pour out, अस्राक्ष्  and असृक्ष्.

880. a. The endings are the usual secondary ones, with उस् (not अन् ) in 3d pl. act., and अत  (not अन्त ) in 3d pl. mid.