take hold and find
support, and so be able to pass through all places, carrying on high the
dwelling-place of the most sacred and divine part of us. Such was the
origin of legs and hands, which for this reason were attached to every
man; and the gods, deeming the front part of man to be more honourable
and more fit to command than the hinder part, made us to move mostly in
a forward direction. Wherefore man must needs have his front part unlike
and distinguished from the rest of his body.

And so in the vessel of the head, they first of all put a face in which
they inserted organs to minister in all things to the providence of the
soul, and they appointed this part, which has authority, to be by nature
the part which is in front. And of the organs they first contrived
the eyes to give light, and the principle according to which they were
inserted was as follows: So much of fire as would not burn, but gave
a gentle light, they formed into a substance akin to the light of
every-day life; and the pure fire which is within us and related
thereto they made to flow through the eyes in a stream smooth and dense,
compressing the whole eye, and especially the centre part, so that it
kept out everything of a coarser nature, and allowed to pass only this
pure element. When the light of day surrounds the stream of vision,
then like falls upon like, and they coalesce, and one body is formed by
natural affinity in the line of vision, wherever the light that falls
from within meets with an external object. And the whole stream of
vision, being similarly affected in virtue of similarity, diffuses the
motions of what it touches or what touches it over the whole body, until
they reach the soul, causing that perception which we call sight. But
when night comes on and the external and kindred fire departs, then the
stream of vision is cut off; for going forth to an unlike element it
is changed and extinguished, being no longer of one nature with the
surrounding atmosphere which is now deprived of fire: and so the eye no
longer sees, and we feel disposed to sleep. For when the eyelids, which
the gods invented for the preservation of sight, are closed, they keep
in the internal fire; and the power of the fire diffuses and equalizes
the inward motions; when they are equalized, there is rest, and when the
rest is profound, sleep comes over us scarce disturbed by dreams;
but where the greater motions still remain, of whatever nature and in
wha