Śatapatha Brāhmaṇa ("of a hundred paths") 11.4.1.12

11.4.1.12

atha yadapuro'nuvākyakāḥ prayājā bhavanti tasmādimāḥ prajā adantakā jāyante'tha yatpuro'nuvākyavanti havīṃṣi bhavanti tasmādāsāṃ jāyante'tha yadapuro'nuvākyakā anuyājā bhavanti tasmādāsām prabhidyante'tha yatpuro'nuvākyavantaḥ patnīsaṃyājā bhavanti tasmādāsāṃ saṃtiṣṭhante'tha yadapuro'nuvākyakaṃ samiṣṭayajurbhavati tasmādāsām punaruttame vayasi sarva eva prabhidyante

And inasmuch as the fore-offerings are without invitatory formulas, therefore creatures are horn here without teeth; and inasmuch as the chief oblations have invitatory formulas, therefore they (the teeth) grow in them; and inasmuch as the after-offerings are without invitatory formulas, therefore they (the teeth) decay in them; and inasmuch as the Patnîsamyâgas as have invitatory formulas, therefore they (the teeth) come to remain permanently with them; and inasmuch as the Samishtayagus is without invitatory formula, therefore they all decay again in the last stage of life.