When the blood supplied for the various processes which are carried on
in the living body has undergone a certain degree of change, it requires
to be purified by the act of respiration. For this purpose it is urged
onwards by fresh blood from behind into the veins; and returning in them
from all parts of the body, enters a cavity of the heart called the
_right auricle_. At the same time the purified blood returning from the
lungs by the pulmonary veins, passes into the _left auricle_. When these
two cavities, which are distinct from each other, are sufficiently
dilated, they contract, and force the blood which they contain into two
other much more muscular cavities called respectively the right and left
_ventricle_, all retrogression into the auricles being prevented by
valves, which admit of a passage in one direction only. The ventricles
then contract in their turn with great force, and at the same instant;
and propel their blood, the right, by the pulmonary artery into the
lungs; the left, which is much the stronger of the two, into all parts
of the body, by the great artery called the _aörta_, and its branches;
all return being prevented as before by valves situated at the orifices
of those vessels, which are closed most accurately when the ventricles
relax, by the backward pressure of the blood arising from the elasticity
of the arteries. Thus the purified blood passes from the lungs by the
pulmonary veins through the left auricle into the ventricle of the same
side, by which it is distributed into all parts of the body, driving the
vitiated blood before it; and the vitiated blood is pushed into and
along the veins to the right auricle, and thence is sent into the right
ventricle, which propels it by the pulmonary artery through the lungs.
In this manner a double circulation is kept up by the sole agency of the
heart, through the lungs, and through the body; the contractions of the
auricles and ventricles taking place alternately. To prevent any
backward motion of the blood in the superficial veins, which might
happen from their liability to external pressure, they are also provided
with simple and very complete valves which admit of a passage only
towards the heart. They were first remarked by Fabricius ab
Aquapendente, and exhibited in his lectures to Harvey among the rest of
his pupils; but their function remained a mystery till it was explained
by the discovery of the circulation. It is related by Boyle, upon
Harvey’s own authority, that the first idea of this comprehensive
principle suggested itself to him when considering the structure of
these valves.
The pulmonary circulation had been surmised by Galen, and maintained by
his successors; but no proof even of this insulated portion of the
truth, more than amounted to strong probability, had been given till the
time of Harvey; and no plausible claim to the discovery, still less to
the demonstration, of the general circulation has ever been set up in
opposition to his. Indeed its truth was quite inconsistent with the
ideas everywhere entertained in the schools on the functions of the
heart and other viscera, and was destructive of many favourite theories.
The new doctrine, therefore, as may well be supposed, was received by
most of the anatomists of the period with distrust, and by all with
surprise. Some of them undertook to refute it; but their objections
turned principally on the silence of Galen, or consisted of the most
frivolous cavils: the controversy, too, assumed the form of personal
abuse even more speedily than is usually the case when authority is at
issue with reason. To such opposition Harvey for some time did not think
it necessary to reply; but some of his friends in England, and of the
adherents to his doctrine on the Continent, warmly took up his defence.
At length he was induced to take a personal share in the dispute in
answer to Riolanus, a Parisian anatomist of some celebrity, whose
objections were distinguished by some show of philosophy, and unusual
abstinence from abuse. The answer was conciliatory and complete, but
ineffectual to produce conviction; and in reply to Harvey’s appeal to
direct experiment, his opponent urged nothing but conjecture and
assertion. Harvey once more rejoined at considerable length; taking
occasion to give a spirited rebuke to the unworthy reception he had met
with, in which it seems that Riolanus had now permitted himself to join;
adducing several new and conclusive experiments in support of his
theory; and entering at large upon its value in simplifying physiology
and the study of diseases, with other interesting collateral topics.
Riolanus, however, still remained unconvinced; and his second rejoinder
was treated by Harvey with contemptuous silence. He had already
exhausted the subject in the two excellent controversial pieces just
mentioned, the last of which is said to have been written at Oxford
about 1545; and he never resumed the discussion in print. Time had now
come to the assistance of argument, and his discovery began to be
generally admitted. To this indeed his opponents contributed by a still
more singular discovery of their own, namely, that the facts had been
observed, and the important inference drawn long before. This was the
mere allegation of envy, chafed at the achievements of another, which,
from their apparent facility, might have been its own. It is indeed
strange that the simple mechanism thus explained should have been
unobserved or misunderstood so long; and nothing can account for it but
the imperceptible lightness as well as the strength of the chains which
authority imposes on the mind.
In the year 1623 Harvey became Physician Extraordinary to James I., and
seven years later was appointed Physician to Charles. He followed the
fortunes of that monarch, who treated him with great distinction, during
the first years of the civil war, and he was present at the battle of
Edgehill in 1642. Having been incorporated Doctor of Physic by the
University of Oxford, he was promoted by Charles to the Wardenship of
Merton College in 1645; but he did not retain this office very long, his
predecessor Dr. Brent being reinstated by the parliament after the
surrender of Oxford in the following year.
Harvey then returned to London and resided with his brother Eliab at
Cockaine-house in the Poultry. About the time of Charles’s execution he
gave up his practice, which had never been considerable, probably in
consequence of his devotion to the scientific, rather than the practical
parts of his profession. He himself, however, attributed his want of
success to the enmity excited by his discovery. After a second visit to
the Continent, he secluded himself in the country, sometimes at his own
house in Lambeth, and sometimes with his brother Eliab at Combe in
Surrey. Here he was visited by his friend Dr. Ent in 1651, by whom he
was persuaded to allow the publication of his work on the Generation of
Animals. It was the fruit of many years of experiment and meditation;
and though the vehicle of no remarkable discovery, is replete with
interest and research, and contains passages of brilliant and even
poetical eloquence. The object of his work is to trace the germ through
all its changes to the period of maturity; and the illustrations are
principally drawn from the phenomena exhibited by eggs in the process of
incubation, which he watched with great care, and has described with
minuteness and fidelity. The microscope had not at that time the
perfection it has since attained; and consequently Harvey’s account of
the first appearance of the chick is somewhat inaccurate, and has been
superseded by the observations of Malpighi, Hunter, and others. The
experiments upon which he chiefly relied in this department of natural
history had been repeated in the presence of Charles I., who appears to
have taken great interest in the studies of his physician.
In the year 1653, the seventy-fifth of his life, Harvey presented the
College of Physicians with the title-deeds of a building erected in
their garden, and elegantly fitted up at his expense, with a library and
museum, and commodious apartments for their social meetings. Upon this
occasion he resigned the Professorship of Anatomy, which he had held for
nearly forty years, and was succeeded by Dr. Glisson.
In 1654 he was elected to the Presidency of the College, which he
declined on the plea of age; and the former President, Sir Francis
Prujean, was re-elected at his request. Two years afterwards he made a
donation to the college of a part of his patrimonial estate to the
yearly value of £56, as a provision for the maintenance of the library
and an annual festival and oration in commemoration of benefactors.
At length his constitution, which had long been harassed by the gout,
yielded to the increasing infirmities of age, and he died in his
eightieth year, on the 3d of June, 1657. He was buried at Hempstead in
Essex, in a vault belonging to his brother Eliab, who was his principal
heir, and his remains were followed to the grave by a numerous
procession of the body of which he had been so illustrious and
munificent a member.
The best edition of his works is that edited by the College of
Physicians in 1766, to which is prefixed a valuable notice of his life,
and an account of the controversy to which his discovery of the
circulation gave rise. All that remain of his writings in addition to
those which have been already mentioned, are an account of the
dissection of Thomas Parr, who died at the age of 153, and a few letters
addressed to various Continental anatomists. His lodgings at Whitehall
had been plundered in the early part of the civil war, of many papers
containing manuscript notes of experiments and observations, chiefly
relating to comparative anatomy. This was a loss which he always
continued to lament. The missing papers have never been recovered.
In person he was below the middle size, but well-proportioned. He had a
dark complexion, black hair, and small lively eyes. In his youth his
temper is said to have been very hasty. If so he was cured of this
defect as he grew older; for nothing can be more courteous and temperate
than his controversial writings, and the genuine kindness and modesty
which were conspicuous in all his dealings with others, with his
instructive conversation, gained him many attached and excellent
friends. He was fond of meditation and retirement; and there is much in
his works to characterize him as a man of warm and unaffected piety.
There are several histories of his life; a very elegant one has lately
been published in a volume of the Family Library, entitled ‘Lives of
British Physicians.’
[Illustration:
_Engraved by C. E. Wagstaff._