Hiranyakeshigrihyasutra 1.1.4.9

1.1.4.9

tamapareṇāgnimudañcamupaveśya hutoccheṣaṇaṃ prāśayati \ tvayi medhāṃ tvayi prajām \ ityetaiḥ saṃnataiḥ \9\

(The teacher) makes him sit down to the west of the fire, facing the north, and makes him eat the remnants of the sacrificial food, with these (Mantras), 'On thee may wisdom, on thee may offspring' (Taitt. Âranyaka, Andhra redaction, X, 44),—altering (the text of the Mantras).