Mbh 12.187.3

"'"Bhrigu said, 'It is true that upon the consumption of fuel fire is no longer seen. It mingles with space because there is no longer any visible object in which to inhere, and hence it becomes incapable of perception by us. Similarly, upon leaving the body, the creature lives in space, and cannot be seen in consequence of its extreme subtility as is doubtless the case with fire. It is fire or heat that sustains the breaths called Prana and the others. Know that that heat (thus existing) is called life or the living agent. That heat which is the sustainer of the breaths, becomes extinguished in consequence of the suppression of breath. Upon that heat in the physical frame being extinguished, the frame itself loses animation. Falling down, it is transformed into earth, for that is its ultimate destination. The breath that is in all mobile and immobile objects mingles with space, and the heat that is in them follows that breath. These three (viz., space, air, and fire), mingle together. The other two (viz., water and earth), exist together in the form of earth. There is wind where space is, and there is fire where wind is. They are formless, it should be known, and become endued with form only in respect of embodied creatures.'