BṚHADĀRAṆYAKA UPANISHAD · 4.2.3

अथैतद् वामे ऽक्षणि पुरुषरूपम् एषास्य पत्नी विराट् ।
तयोर् एष संस्तावो य एषो ऽन्तर् हृदय आकाशः ।
अथैनयोर् एतद् अन्नं य एषो ऽन्तर् हृदये लोहितपिण्डः ।
अथैनयोर् एतत् प्रावरणं यद् एतद् अन्तर् हृदये जालकम् इव ।
अथैनयोर् एषा सृतिः संचरणी यैषा हृदयाद् ऊर्ध्वा नाड्य् उच्चरति ।
यथा केशः सहस्रधा भिन्न एवम् अस्यैता हिता नाम नाड्यो ऽन्तर् हृदये प्रतिष्ठिता भवन्ति ।
एताभिर् वा एतद् आस्रवद् आस्रवति ।
तस्माद् एष प्रविविक्ताहारतर इव भवत्य् अस्माच् छारीराद् आत्मनः ॥

athaitad vāme ’kṣaṇi puruṣarūpam eṣāsya patnī virāṭ ।
tayor eṣa saṃstāvo ya eṣo ’ntar hṛdaya ākāśaḥ ।
athainayor etad annaṃ ya eṣo ’ntar hṛdaye lohitapiṇḍaḥ ।
athainayor etat prāvaraṇaṃ yad etad antar hṛdaye jālakam iva ।
athainayor eṣā sṛtiḥ saṃcaraṇī yaiṣā hṛdayād ūrdhvā nāḍy uccarati ।
yathā keśaḥ sahasradhā bhinna evam asyaitā hitā nāma nāḍyo ’ntar hṛdaye pratiṣṭhitā bhavanti ।
etābhir vā etad āsravad āsravati ।
tasmād eṣa praviviktāhāratara iva bhavaty asmāc chārīrād ātmanaḥ ॥

'Now that which in the shape of a person is in the right eye, is his wife, Virâg. Their meeting-place is the ether within the heart, and their food the red lump within the heart. Again, their covering is that which is like net-work within the heart, and the road on which they move (from sleep to waking) is the artery that rises upwards from the heart. Like a hair divided into a thousand parts, so are the veins of it, which are called Hita, placed firmly within the heart. Through these indeed that (food) flows on flowing, and he (the Taigasa) receives as it were purer food than the corporeal Self (the Vaisvânara).

F. Max Müller · The Upanishads, Sacred Books of the East 15 (1884)