Shatapatha Brahmana 10.1.4.3

10.1.4.3

dvitīyāṃ citiṃ cinoti sā hāsyaiṣāpāna eva tadvai tadamṛtamamṛtaṃ hyapānaḥ saiṣāmṛtacitistadetanmartyamubhayato'mṛtena parigṛhṇāti tenāsyaitadamṛtam bhavatyatha purīṣaṃ nivapati taddhāsyaitadasthyeva tadvai tanmartyam martyaṃ hyasthi tadetasminnamṛte pratiṣṭhāpayati tenāsyaitadamṛtam bhavati

He lays down the second layer,--this, doubtless, is his downward breathing, and it is an immortal (element), for the downward breathing is something immortal: this, then, is an immortal layer. He thus encompasses that mortal (element) on both sides by an immortal one, and thereby that part of him becomes immortal. He then scatters loose soil thereon,--this, doubtless, is his bones, and it is a mortal (element), for the bone is mortal: he establishes it on that immortal (element), and thereby this part of him becomes immortal.