No. XIV.
THE CIRCULATION OF THE BLOOD, &c.
Two thousand years have elapsed since the time of Hippocrates, and there
has scarcely been added a new aphorism to those of that great man,
notwithstanding all the care and application of so many ingenious men as
have since studied medicine.
There exist evident proofs that Hippocrates was acquainted with the
circulation of the blood. Almelooven, in vindication of this father of
medicine not having more amply treated of this subject in his works,
assigns this reason, that Hippocrates having many other important
matters to discuss, judged that to enlarge upon what was so well known,
and had been so well explained by others, was as needless as it would
have been to have written an Iliad after Homer. It is less requisite
here to cite passages as proofs of Hippocrates’s knowledge on this vital
principle in the animal economy, than to state the fact of his
acquaintance with it. Briefly it may suffice to mention, that
Hippocrates compares the course of rivers, which return to their sources
in an unaccountable and extraordinary manner, _to the circulation of the
blood_. He says, that “when the bile enters into the blood it breaks its
consistence, and disorders its regular course.” He compares the
admirable mechanism of the blood “to clues of thread, whose filaments
overlap each other;” and he says, that “_in the body it performs just
such a circuit, always terminating where it began_.”
Mr. Dutens is of opinion that Plato, Aristotle, Julius Pollux, Apuleius,
and other ancients, treat the circulation of the blood as well known in
their time. To that end he cites passages from their writings, and
proceeds to affirm, that what reduces to a very small degree the honour
of Harvey’s claim to the discovery is, that Servetus had treated of it
very distinctly before him, in the fifth part of his book _De
Christianismi Restitutione_; a work so very scarce, that there are but
few who can boast of having seen it in print. Mr. Wotton, in his
_Reflections upon the Ancients and Moderns_, cites this passage of
Servetus entire. In this passage Servetus distinguishes three sorts of
spirits in the human body, and says that blood, “which he calls a vital
spirit, is dispersed through the body by the _anastomosis_, or mutual
insertion of two vessels, at their extremities, into one another.” Here
it deserves observation, that Servetus is the first who employed that
term to express the communication between the veins and arteries. He
makes “the expanded air in the lungs contribute to the formation of
blood, which comes to them from the right ventricle of the heart, by the
canal of the pulmonary artery.” He says, that “the blood is there
refined and perfected by the action of the air, which subtilises it and
blends itself with that vital spirit, which the expanded heart then
receives as a fluid proper to carry life every where.” He maintains that
“this conveyance and manner of preparing the blood in the lungs is
evident from the junction of the veins with the arteries in this
viscera.” And he concludes with saying, that “the heart having received
the blood thus prepared by the lungs sends it forth again by the artery
of its left ventricle, called the aorta, which distributes it into all
parts of the body.” Andreas Cesalpinus, who lived likewise in the
sixteenth century, has two passages which completely contain all that we
know about the circulation of the blood. He explains at length “how the
blood, gushing from the right ventricle of the heart through the
pulmonary artery to pass into the lungs, enters anastomosically into the
pulmonary veins, to be conveyed to the left ventricle of the heart, and
afterwards distributed by the aorta into all parts of the body.” Let it
be remarked, that, according to Boerhaave, the first edition of
Cesalpin’s book was at Venice in 1571; that is, almost sixty years
before Harvey’s work appeared, who studied at Padua, which is not far
from Venice; and spent a considerable part of his time there.
Johannes Leonicenus says, that the famous Paul Sarpi, otherwise known by
the name of Father Paul, was he who discovered the circulation of the
blood, and first discerned “the valves of the veins, which, like the
suckers of a pump, open to let the blood pass, but shut to prevent its
return;” and that he communicated this secret to Fabricius ab
Aquapendente, professor of medicine at Padoua in the sixteenth century,
and successor to Fallopius, who discovered it to Harvey, at that time
studying physic under him in the university of Padoua.