Śatapatha Brāhmaṇa ("of a hundred paths") 8.7.2.9

8.7.2.9

sa vā ātmanneva | yajuṣmatīrupadadhāti na pakṣapuceṣvātmaṃstadannaṃ dadhāti yadu vā ātmannannaṃ dhīyate tadātmānamavati tatpakṣapucānyatha yatpakṣapuceṣu naiva tadātmānamavati na pakṣapucāni

Those (bricks) possessed of formulas he places on the body (of the altar) itself, not on the wings and tail: he thus puts food into the body; and whatever food is put into the body that benefits both the body and the wings and tail; but that which he puts on the wings and tail benefits neither the body, nor the wings and tail.