underneath the skin； where it took root。 Thus the hair sprang up in
the skin； being akin to it because it is like threads of leather；
but rendered harder and closer through the pressure of the cold； by
which each hair； while in process of separation from the skin； is
compressed and cooled。 Wherefore the creator formed the head hairy；
making use of the causes which I have mentioned； and reflecting also
that instead of flesh the brain needed the hair to be a light covering
or guard； which would give shade in summer and shelter in winter；
and at the same time would not impede our quickness of perception。
From the combination of sinew； skin； and bone； in the structure of the
finger； there arises a triple compound； which； when dried up； takes
the form of one hard skin partaking of all three natures； and was
fabricated by these second causes； but designed by mind which is the
principal cause with an eye to the future。 For our creators well
knew that women and other animals would some day be framed out of men；
and they further knew that many animals would require the use of nails
for many purposes； wherefore they fashioned in men at their first
creation the rudiments of nails。 For this purpose and for these
reasons they caused skin； hair； and nails to grow at the extremities
of the limbs。 And now that all the parts and members of the mortal
animal had come together； since its life of necessity consisted of
fire and breath； and it therefore wasted away by dissolution and
depletion； the gods contrived the following remedy： They mingled a
nature akin to that of man with other forms and perceptions； and
thus created another kind of animal。 These are the trees and plants
and seeds which have been improved by cultivation and are now
domesticated among us； anciently there were only the will kinds； which
are older than the cultivated。 For everything that partakes of life
may be truly called a living being； and the animal of which we are now
speaking partakes of the third kind of soul； which is said to be
seated between the midriff and the navel； having no part in opinion or
reason or mind； but only in feelings of pleasure and pain and the
desires which accompany them。 For this nature is always in a passive
state； revolving in and about itself； repelling the motion from
without and using its own； and accordingly is not endowed by nature
with the power of observing or reflecting on its own concerns。
Wherefore it lives and does not differ from a living being； but is
fixed and rooted in the same spot； having no power of self…motion。
Now after the superior powers had created all these natures to be
food for us who are of the inferior nature； they cut various
channels through the body as through a garden； that it might be
watered as from a running stream。 In the first place； they cut two
hidden channels or veins down the back where the skin and the flesh
join； which answered severally to the right and left side of the body。
These they let down along the backbone； so as to have the marrow of
generation between them； where it was most likely to flourish； and
in order that the stream coming down from above might flow freely to
the other parts； and equalise the irrigation。 In the next place；
they divided the veins about the head； and interlacing them； they sent
them in opposite directions； those coming from the right side they
sent to the left of the body； and those from the left they diverted
towards the right； so that they and the skin might together form a
bond which should fasten the head to the body； since the crown of
the head was not encircled by sinews； and also in order that the
sensations from both sides might be distributed over the whole body。
And next； they ordered the water…courses of the body in a manner which
I will describe； and which will be more easily understood if we
begin by admitting that all things which have lesser parts retain
the greater； but the greater cannot retain the lesser。 Now of all
natures fire has the smallest parts； and therefore penetrates
through earth and water and air and their compounds； nor can
anything hold it。 And a similar principle applies to the human
belly； for when meats and drinks enter it； it holds them； but it
cannot hold air and fire； because the particles of which they
consist are smaller than its own structure。
These elements； therefore； God employed for the sake of distributing
moisture from the belly into the veins； weaving together network of
fire and air like a weel； having at the entrance two lesser weels；
further he constructed one of these with two openings； and from the
lesser weels he extended cords reaching all round to the extremities
of the network。 All the interior of the net he made of fire； but the
lesser weels and their cavity； of air。 The network he took and
spread over the newly…formed animal in the following manner：…He let
the lesser weels pass into the mouth； there were two of them； and
one he let down by the air…pipes into the lungs； the other by the side
of the air…pipes into the belly。 The former he divided into two
branches； both of which he made to meet at the channels of the nose；
so that when the way through the mouth did not act； the streams of the
mouth as well were replenished through the nose。 With the other cavity
（i。e。 of the greater weel） he enveloped the hollow parts of the
body； and at one time he made all this to flow into the lesser
weels； quite gently； for they are composed of air； and at another time
he caused the lesser weels to flow back again； and the net he made
to find a way in and out through the pores of the body； and the rays
of fire which are bound fast within followed the passage of the air
either way； never at any time ceasing so long as the mortal being
holds together。 This process； as we affirm； the name…giver named
inspiration and expiration。 And all this movement； active as well as
passive； takes place in order that the body； being watered and cooled；
may receive nourishment and life； for when the respiration is going in
and out； and the fire； which is fast bound within； follows it； and
ever and anon moving to and fro； enters through the belly and
reaches the meat and drink； it dissolves them； and dividing them
into small portions and guiding them through the passages where it
goes； pumps them as from a fountain into the channels of the veins；
and makes the stream of the veins flow through the body as through a
conduit。
Let us once more consider the phenomena of respiration； and
enquire into the causes which have made it what it is。 They are as
follows：…Seeing that there is no such thing as a vacuum into which any
of those things which are moved can enter； and the breath is carried
from us into the external air； the next point is； as will be dear to
every one； that it does not go into a vacant space； but pushes its
neighbour out of its place； and that which is thrust out in turn
drives out its neighbour； and in this everything of necessity at
last comes round to that place from whence the breath came forth；
and enters in there； and following the breath； fills up the vacant
space； and this goes on like the rotation of a wheel； because there
can be no such thing as a vacuum。 Wherefore also the breast and the
lungs； when they emit the breath； are replenished by the air which
surrounds the body and which enters in through the pores of the
flesh and is driven round in a circle； and again； the air which is
sent away and passes out through the body forces the breath inwards
through the passage of the mouth and the nostrils。 Now the origin of
this movement may be supposed to be as follows。 In the interior of
every animal the hottest part is that which is around the blood and
veins； it is in a manner on internal fountain of fire； which we
compare to the network of a creel； being woven all of fire and
extended through the centre of the body； while the…outer parts are
composed of air。 Now we must admit that heat naturally proceeds
outward to its own place and to its kindred element； and as there
are two exits for the heat； the out through the body； and the other
through the mouth and nostrils； when it moves towards the one； it
drives round the air at the other； and that which is driven round
falls into the fire and becomes warm； and that which goes forth is
cooled。 But when the heat changes its place； and the particles at
the other exit grow warmer； the hotter air inclining in that direction
and carried towards its native element； fire； pushes round the air
at the other； and this being affected in the same way and
communicating the same impulse； a circular motion swaying to and
from is produced by the double process； which we call inspiration
and expiration。
The phenomena of medical cupping…glasses and of the swallowing of
drink and of the projection of bodies； whether discharged in the air
or bowled along the ground； are to be investigated on a similar
principle； and swift and slow sounds； which appear to be high and low；
and are sometimes discordant on account of their inequality； and
then again harmonical on account of the equality of the motion which
they excite in us。 For when the motions of the antecedent swifter
sounds begin to pause and the two are equalised； the slower sounds
overtake the swifter and then propel them。 When they overtake them
they do not intrude a new and discordant motion； but introduce the
beginnings of a slower； which answers to the swifter as it dies
away； thus producing a single mixed expression out of high and low；
whence arises a pleasure which even the unwise feel； and which to
the wise becomes a higher sort of delight； being an imitation of
divine harmony in mortal motions。 Moreover； as to the flowing of
water； the fall of the thunderbolt； and the marvels that are
observed about the attraction of amber and the Heraclean stones；…in
none of these cases is there any attraction； but he who investigates
rightly； will find that such wonderful phenomena are attributable to
the combination of certain conditions…the non…existence of a vacu