Śatapatha Brāhmaṇa ("of a hundred paths") 8.1.4

Now some lay down (these bricks) so as to be in contact with the (gold) man, for he is the vital air, and him these (bricks) sustain; and because they sustain (bhri) the vital air (prâna), therefore they are called 'Prânabhritah.' Let him not do so: the vital air is indeed the same as that gold man, but this body of his extends to as far here as this fire (altar) has been marked out. Hence to whatever limb of his these (breath-holders) were not to reach, that limb of his the vital air would not reach; and, to be sure, to whatever limb the vital air does not reach, that either dries up or withers away: let him therefore lay down these (bricks) so as to be in contact with the enclosing stones; and by those which he lays down in the middle this body of his is filled up, and they at least are not separated from him.

Here now they say, 'Whereas in (the formulas) "This one, in front, the existent--this one, on the right, the all-worker--this one, behind, the all-embracer--this, on the left, heaven--this one, above, the mind"--they (these bricks) are defined as exactly opposite the quarters, why, then, does he lay down these (bricks) in sidelong places?' Well, the Prânabhritah are the vital airs; and if he were to place them exactly opposite the quarters, then this breath would only pass forward and backward; but inasmuch as he now lays down these (bricks) thus defined in sidelong places, therefore this breath, whilst being a backward and forward one, passes sideways along all the limbs and the whole body.

Now that Agni (the altar) is an animal, and (as such) he is even now made up whole and entire,--those (bricks) which he lays down in front are his fore-feet, and those behind are his thighs; and those which he places in the middle are that body of his. He places these in the region of the two retahsik (bricks), for the retahsik are the ribs, and the ribs are the middle, and that body is in the middle (of the limbs). He places them all round, for that body extends all round.

Here now they say, 'Whereas in the first (four) sets he lays down a single stoma and a single prishtha each time, why, then, does he lay down here (in the centre) two stomas and two prishthas?' Well, this (central set) is his (Agni's) body: he thus makes the body (trunk) the best, the largest, the most vigorous of limbs; whence that body is the best, the largest, and most vigorous of limbs.

Here now they say, 'How does that Agni of his become made up whole and entire in brick after brick?'--Well, the formula is the marrow, the brick the bone, the settling the flesh, the sûdadohas the skins, the formula of the purîsha (fillings of earth) the hair, and the purîsha the food: and thus indeed that Agni of his becomes made up whole and entire in brick after brick.

That Agni is possessed of all vital power: verily, whosoever knows that Agni to be possessed of all vital power (âyus), attains his full measure of life (âyus).

Now, then, as to the contraction and expansion (of the body). Now some cause the built (altar) in this way to be possessed of (the power of) contraction and expansion: that Agni indeed is an animal; and when an animal contracts and expands its limbs, it develops strength by them.

[Vâg. S. XXVII, 45] 'Thou art Samvatsara,--thou art Parivatsara,--thou art Idâvatsara,--thou art Idvatsara,--thou art Vatsara,--May thy dawns prosper!--may thy days and nights prosper!--may thy half-months prosper!--may thy months prosper!--may thy seasons prosper!--may thy year prosper!--For going and coming contract and expand thyself!--Of Eagle-build thou art: by that deity, Aṅgiras-like, lie thou steady!'

Sâtyâyani also once said, 'Some one heard (the sound) of the cracking wings of the (altar)-when touched with this (formula): let him therefore by all means touch it therewith!'

And Svargit Nâgnagita or Nagnagit, the Gândhâra, once said, 'Contraction and expansion surely are the breath, for in whatever part of the body there is breath that it both contracts and expands; let him breathe upon it from outside when completely built: he thereby lays breath, the (power of) contraction and expansion, into it, and so it contracts and expands.' But indeed what he there said as to that contraction and expansion, it was only one of the princely order who said it; and assuredly were they to breathe upon it from outside a hundred times, or a thousand times, they could not lay breath into it. Whatever breath there is in the (main) body that alone is the breath: hence when he lays down the Prânabhritah (breath-holders), he thereby lays breath, the (power of) contraction and expansion, into it; and so it contracts and expands. He then lays down two Lokamprinâ (bricks) in that corner: the meaning of them (will be explained) further on. He throws loose earth (on the layer): the meaning of this (will be explained) further on.