Śatapatha Brāhmaṇa ("of a hundred paths") 10.2.3.5

10.2.3.5

tadāhuḥ kathameṣa saptavidha etayā vedyā sampadyata iti daśa vā ime puruṣe prāṇāścatvāryaṅgānyātmā pañcadaśa evaṃ dvitīya evaṃ tṛtīye ṣaṭsu puruṣeṣu navatirathaikaḥ puruṣo'tyeti pāṅkto vai puruṣo loma tvaṅmāṃsamasthi majjā pāṅkto iyaṃ vediścatasro diśa ātmā pañcamyevameṣa saptavidha etayā vedyā sampadyate

As to this they say, 'How does this sevenfold (Person, the fire-altar,) correspond to this Vedi (measuring ninety steps)?' Well, there are these ten vital airs in a man, four limbs, and the trunk as the fifteenth; in the same way in the second, and in the same way in the third (man),--in six men this makes ninety; and one man remains over. Now, (that seventh) man is fivefold--hair, skin, flesh, bone, and marrow (fat), and this Vedi also is fivefold--the four regions (quarters), and the body (of the altar) as the fifth: thus this sevenfold (altar) does indeed correspond to this Vedi.