Śatapatha Brāhmaṇa ("of a hundred paths") 4.2.5.3

4.2.5.3

atha stīrṇāyai vedeḥ | dve tṛṇe adhvaryurādatte tāvadhvaryū prathamau pratipadyete prāṇodānau yajñasyātha prastotā vāgeva yajñasyāthodgātātmaiva prajāpatiryajñasyātha pratihartā bhiṣagvā vyāno vā

Thereupon the Adhvaryu takes two stalks of grass from the covered altar. The two Adhvaryus proceed first (to the chanting-place beside the pit), as the out-breathing and in-breathing of the sacrifice; then the Prastotri, as the voice of the sacrifice; then the Udgâtri, as the self (or body), the Pragâpati, of the sacrifice; then the Pratihartri, either as the physician or the through-breathing.