190. The rule has force

The rule has force especially—

a. When suffixes, of influence or derivation, are added to roots or stems containing one of the altering sounds; thus, rudréṇa, rudrā́ṇām, vā́riṇe, vā́riṇī, vā́rīṇi, dātṝ́ṇi, hárāṇi, dvéṣāṇi, krīṇā́mi, çṛṇóti, kṣubhāṇá, ghṛṇá, kárṇa, vṛkṇá, rugṇá, dráviṇa, iṣáṇi, purāṇá, rékṇas, cákṣaṇa, cíkīrṣamāṇa, kṛ́pamāṇa.

b. When the final n of a root or stem comes to be followed, in inflection or derivation, by such sounds as allow it to feel the effect of a preceding altering cause: thus, from √ran, ráṇanti, ráṇyati, rāraṇa, arāṇiṣus; from brahman, bráhmaṇā, bráhmāṇi, brāhmaṇá, brahmaṇyà, bráhmaṇvant.

c. The form piṇak (RV.: 2d and 3d sing. impf.), from √piṣ, is wholly anomalous.