MuU 2.1.8
सप्त प्राणाः प्रभवन्ति तस्मात् सप्तार्चिषः समिधः सप्त होमाः । सप्त इमे लोका येषु चरन्ति प्राणा गुहाशया निहिताः सप्त सप्त
sapta prāṇāḥ prabhavanti tasmāt saptārciṣaḥ samidhaḥ sapta homāḥ | sapta ime lokā yeṣu caranti prāṇā guhāśayā nihitāḥ sapta sapta
Sanskrit for this text is pending; the English follows the translator's numbering.
The seven senses (prâna) also spring from him, the seven lights (acts of sensation), the seven kinds of fuel (objects by which the senses are lighted), the seven sacrifices (results of sensation), these seven worlds (the places of the senses, the worlds determined by the senses) in which the senses move, which rest in the cave (of the heart), and are placed there seven and seven.
Translated by F. Max Müller