on the motions of the body
The sanguine spirits enter the
cavities of the brain (the ventricles) and from there...
 |
"enter the pores
(or conduits) in its substance, and from these
conduits proceed to the nerves. And depending on
their entering (or their mere tendency to enter)
some nerves rather than others, they are able to
change the shapes of the muscles into which these
nerves are inserted and in this way to move all
the members. Similarly you may have observed in
the grottoes and fountains in the gardens of our
kings that the force that makes the water leap
from its source is able of itself to move divers
machines and even make them play certain
instruments or pronounce certain words according
to the various arrangements of the tubes through
which the water is conducted."
|
 |
"And
truly one can well compare the nerves of the
machine that I am describing to the tubes of the
mechanisms of these fountains, its muscles and
tendons to divers other engines and springs which
serve to move these mechanisms, its animal
spirits to the water which drives them, of which
the heart is the source and the brain's cavities
the water main. Moreover breathing and other such
actions which are ordinary and natural to it, and
which depend on the flow of the spirits, are like
the movements of the clock or the mill which the
ordinary flow of the water can render continuous.
External objects which merely by their presence
act on the organs of sense and by this means
force them to move in several different ways,
depending on how the different parts of the brain
are arranged, are like strangers who, on entering
some of the grottoes of these fountains,
unwittingly cause the movements that then occur,
since they cannot enter without stepping on
certain tiles which are so arranged that, for
example, if they approach a Diana bathing they
will cause her to hide in the reeds; and if they
pass farther to pursue her they will cause a
Neptune to advance and menace them with his
trident; or if they go in another direction they
will make a marine monster come out and spew
water into their faces, or other such things
according to the whims of the engineers who made
them. And finally when there shall be a rational
soul in this machine, it will have its chief seat
in the brain and will reside there like the
turncock who must be in the main to which all the
tubes of these machines repair when he wishes to
excite, prevent, or in some manner alter their
movements." [Descartes: Traite
de l'Homme (1664)
(T.S.Hall transl.)] |
|