462. In the oldest language

a. In the oldest language (RV.), the vocative sing. masc. (like that of vant and mant- stems: above, 454 b) has the ending vas instead of van: thus, cikitvas(changed to -van in a parallel passage of AV.), titirvas, dīdivas, mīḍhvas.

b. Forms from the middle stem, in vat, are extremely rare earlier: only three (tatanvát and vavṛtvát, neut. sing., and jāgṛvádbhis, instr. pl.), are found in RV., and not one in AV. And in the Veda the weakest stem (not, as later, the middle one) is made the basis of comparison and derivation: thus, vidúṣṭara, ádāçuṣṭara,mīḍhúṣṭama, mīḍhúṣmant.

c. An example or two of the use of the weak stem-form for cases regularly made from the strong are found in RV.: they are cakrúṣam, acc. sing., and ábibhyuṣas, nom. pl.; emuṣám, by its accent (unless an error), is rather from a derivative stem emuṣá; and ÇB. has proṣúṣam. Similar instances, especially from vidvā́ṅs, are now and then met with later (see BR., under vidvā́ṅs).

d. The AV. has once bhaktivā́ṅsas, as if a participial form from a noun; but K. and TB. give in the corresponding passage bhaktivā́nas; cakhvā́ṅsam (RV., once) is of doubtful character; okivā́ṅsā (RV., once) shows a reversion to guttural form of the final of √uc, elsewhere unknown.