THE CIRCULATION OF THE BLOOD IS FURTHER CONFIRMED BY PROBABLE
REASONS
It will not be foreign to the subject if I here show further,
from certain familiar reasonings, that the circulation is matter
both of convenience and necessity. In the first place, since
death is a corruption which takes place through deficiency of
heat, [Footnote: Aristoteles De Respirations, lib. ii et iii: De
Part. Animal. et alibi.] and since all living things are warm,
all dying things cold, there must be a particular seat and
fountain, a kind of home and hearth, where the cherisher of
nature, the original of the native fire, is stored and preserved;
from which heat and life are dispensed to all parts as from a
fountain head; from which sustenance may be derived; and upon
which concoction and nutrition, and all vegetative energy may
depend. Now, that the heart is this place, that the heart is the
principle of life, and that all passes in the manner just
mentioned, I trust no one will deny.
The blood, therefore, required to have motion, and indeed such a
motion that it should return again to the heart; for sent to the
external parts of the body far from its fountain, as Aristotle
says, and without motion it would become congealed. For we see
motion generating and keeping up heat and spirits under ail
circumstances, and rest allowing them to escape and be
dissipated. The blood, therefore, becoming thick or congealed by
the cold of the extreme and outward parts, and robbed of its
spirits, just as it is in the dead, it was imperative that from
its fount and origin, it should again receive heat and spirits,
and all else requisite to its preservation--that, by returning,
it should be renovated and restored.
We frequently see how the extremities are chilled by the external
cold, how the nose and cheeks and hands look blue, and how the
blood, stagnating in them as in the pendent or lower parts of a
corpse, becomes of a dusky hue; the limbs at the same time
getting torpid, so that they can scarcely be moved, and seem
almost to have lost their vitality. Now they can by no means be
so effectually, and especially so speedily restored to heat and
colour and life, as by a new efflux and contact of heat from its
source. But how can parts attract in which the heat and life are
almost extinct? Or how should they whose passages are filled with
condensed and frigid blood, admit fresh aliment--renovated blood
--unless they had first got rid of their old contents? Unless the
heart were truly that fountain where life and heat are restored
to the refrigerated fluid, and whence new blood, warm, imbued
with spirits, being sent out by the arteries, that which has
become cooled and effete is forced on, and all the particles
recover their heat which was failing, and their vital stimulus
wellnigh exhausted.
Hence it is that if the heart be unaffected, life and health may
be restored to almost all the other parts of the body; but if the
heart be chilled, or smitten with any serious disease, it seems
matter of necessity that the whole animal fabric should suffer
and fall into decay. When the source is corrupted, there is
nothing, as Aristotle says, [Footnote: De Part. Animal., iii.]
which can be of service either to it or aught that depends on it.
And hence, by the way, it may perchance be why grief, and love,
and envy, and anxiety, and all affections of the mind of a
similar kind are accompanied with emaciation and decay, or with
disordered fluids and crudity, which engender all manner of
diseases and consume the body of man. For every affection of the
mind that is attended with either pain or pleasure, hope or fear,
is the cause of an agitation whose influence extends to the
heart, and there induces change from the natural constitution, in
the temperature, the pulse and the rest, which impairing all
nutrition in its source and abating the powers at large, it is no
wonder that various forms of incurable disease in the extremities
and in the trunk are the consequence, inasmuch as in such
circumstances the whole body labours under the effects of
vitiated nutrition and a want of native heat.
Moreover, when we see that all animals live through food digested
in their interior, it is imperative that the digestion and
distribution be perfect, and, as a consequence, that there be a
place and receptacle where the aliment is perfected and whence it
is distributed to the several members. Now this place is the
heart, for it is the only organ in the body which contains blood
for the general use; all the others receive it merely for their
peculiar or private advantage, just as the heart also has a
supply for its own especial behoof in its coronary veins and
arteries. But it is of the store which the heart contains in its
auricles and ventricles that I here speak. Then the heart is the
only organ which is so situated and constituted that it can
distribute the blood in due proportion to the several parts of
the body, the quantity sent to each being according to the
dimensions of the artery which supplies it, the heart serving as
a magazine or fountain ready to meet its demands.
Further, a certain impulse or force, as well as an impeller or
forcer, such as the heart, was required to effect this
distribution and motion of the blood; both because the blood is
disposed from slight causes, such as cold, alarm, horror, and the
like, to collect in its source, to concentrate like parts to a
whole, or the drops of water spilt upon a table to the mass of
liquid; and because it is forced from the capillary veins into
the smaller ramifications, and from these into the larger trunks
by the motion of the extremities and the compression of the
muscles generally. The blood is thus more disposed to move from
the circumference to the centre than in the opposite direction,
even were there no valves to oppose its motion; wherefore, that
it may leave its source and enter more confined and colder
channels, and flow against the direction to which it
spontaneously inclines, the blood requires both force and
impelling power. Now such is the heart and the heart alone, and
that in the way and manner already explained.