The Upanishads, Part 1 (SBE01), by Max Müller, , at sacred-texts.com
1. Then he said to them all: 'You eat your food, knowing that Vaisvânara Self as if it were many. But he who worships the Vaisvânara Self as a span long, and as 1 identical with himself, he eats food in all worlds, in all beings, in all Selfs.
2. 'Of that Vaisvânara Self the head is Sutegas (having good light), the eye Visvarûpa (multiform), the breath Prithagvartman (having various courses), the trunk Bahula (full), the bladder Rayi (wealth), the feet the earth, the chest the altar, the hairs the grass on the altar, the heart the Gârhapatya fire, the mind the Anvâhârya fire, the mouth the Âhavanîya fire.
88:1 The two words prâdesamâtra and abhivimâna are doubtful. The commentator explains the first in different ways, which are all more or less fanciful. He is measured or known (mâtra) as Self, p. 89 by means of heaven as his head and the earth as his feet, these being the prâdesas; or, in the mouth and the rest, which are instruments, he is known as without action himself; or, he has the length from heaven to earth, heaven and earth being called prâdesa, because they are taught. The interpretation, supported by the Gâbâlasruti, that prâdesa is the measure from the forehead to the chin, he rejects. Abhivimâna is taken in the same meaning as abhimâna in the Vedânta, seeing everything in oneself. Vaisvânara is taken as the real Self of all beings, and, in the end, of all Selfs, and as thus to be known and worshipped.