ion, and figure of its wheels and of its weight.' Nor, in his
view, does the heart, by virtue of its structure and composition, merely
cause the blood to circulate. 'It also generates animal spirits,' which,
'ascending like a very subtle fluid, or very pure and vivid flame, into
the brain as into a reservoir, pass thence into the nerves, where,
according as they more or less enter, or tend to enter, they have the
power of altering the figures of the muscles into which the nerves are
inserted, and of so causing all the organs and limbs to move.' He puts
the case thus: Even as the ordinary movements of a water-clock or of a
mill are kept up by the ordinary flow of the water, and even as 'in the
grottoes and fountains of royal gardens, the force wherewith the water
issues from its reservoirs suffices to move various machines, and even
to make them play instruments or pronounce words according to the
different disposition of the pipes which lead the water'--even so do
pulsation, respiration, digestion, nutrition, and growth, and 'other
such actions as are natural and usual in the body,' result naturally
from the usual course of the animal spirits. Moreover, even as intruders
upon the waterworks aforesaid unconsciously by their mere presence cause
special movements to take place, even as, for example, 'if they approach
a bathing Diana, they tread on certain planks so arranged as to make her
hide among the reeds, and, if they attempt to follow her, see
approaching a Neptune who threatens with his trident, or rouse some
other monster who vomits water into their faces'--even so do external
objects, by their mere presence, act upon the organs of sense; even so
do 'the reception of light, sounds, odours, flavours, heat, and such
like qualities in the organs of the external senses, the impression of
the ideas of these in the intellect, the imagination, and the memory,
the internal movements of the appetites and passions, and the external
movements which follow so aptly on the presentation of objects to the
senses, or on the resuscitation of impressions by the memory,' yea, even
so do all these 'functions proceed naturally from the arrangement of the
bodily organs, neither more nor less than do the movements of a clock or
other automaton from that of its weights and its wheels, without the aid
of any other vegetative or sensitive soul or any other principle of
motion or of life than the blood and the spirits agitated by the fire
whic