The vital air called Apana is lost in the air called Prana which again is lost in the mind. The last again is lost in the intellect which again is lost in the supreme being. The ascetics perceive that Lord who is Eternal.
अपानं गिरति प्राणः प्राणं गिरति चन्द्रमाः। आदित्यो गिरते चन्द्रमादित्यं गिरते परः। योगिनस्तं प्रपश्यन्ति भगवन्तं सनातनम्॥