THE MOTION AND CIRCULATION OF THE BLOOD ARE CONFIRMED FROM THE
PARTICULARS APPARENT IN THE STRUCTURE OF THE HEART, AND FROM THOSE
THINGS WHICH DISSECTION UNFOLDS.
I do not find the heart as a distinct and separate part in all animals;
some, indeed, such as the zoophytes, have no heart; this is because
these animals are coldest, of no great bulk, of soft texture or of a
certain uniform sameness or simplicity of structure; among the number I
may instance grubs and earthworms, and those that are engendered of
putrefaction and do not preserve their species. These have no heart, as
not requiring any impeller of nourishment into the extreme parts; for
they have bodies which are connate and homogeneous, and without limbs;
so that by the contraction and relaxation of the whole body they assume
and expel, move and remove the aliment. Oysters, mussels, sponges, and
the whole genus of zoophytes or plant-animals have no heart; for the
whole body is used as a heart, or the whole animal is a heart. In a
great number of animals, almost the whole tribe of insects, we cannot
see distinctly by reason of the smallness of the body; still in bees,
flies, hornets, and the like, we can perceive something pulsating with
the help of a magnifying glass; in pediculi, also, the same thing may be
seen, and as the body is transparent, the passage of the food through
the intestines, like a black spot or stain, may be perceived by the aid
of the same magnifying glass.
In some of the bloodless[96] and colder animals, further, as in snails,
whelks, shrimps, and shell-fish, there is a part which pulsates--a kind
of vesicle or auricle without a heart--slowly indeed, and not to be
perceived save in the warmer season of the year. In these creatures this
part is so contrived that it shall pulsate, as there is here a necessity
for some impulse to distribute the nutritive fluid, by reason of the
variety of organic parts, or of the density of the substance; but the
pulsations occur unfrequently, and sometimes in consequence of the cold
not at all, an arrangement the best adapted to them as being of a
doubtful nature, so that sometimes they appear to live, sometimes to
die; sometimes they show the vitality of an animal, sometimes of a
vegetable. This seems also to be the case with the insects which conceal
themselves in winter, and lie, as it were, defunct, or merely
manifesting a kind of vegetative existence. But whether the same thing
happens in the case of certain animals that have red blood, such as
frogs, tortoises, serpents, swallows, may be made a question without any
kind of impropriety.
In all the larger and warmer, because [red-]blooded animals, there was
need of an impeller of the nutritive fluid, and that perchance
possessing a considerable amount of power. In fishes, serpents, lizards,
tortoises, frogs, and others of the same kind there is a heart present,
furnished with both an auricle and a ventricle, whence it is perfectly
true, as Aristotle has observed,[97] that no [red-]blooded animal is
without a heart, by the impelling power of which the nutritive fluid is
forced, both with greater vigour and rapidity to a greater distance; it
is not merely agitated by an auricle as it is in lower forms. And then
in regard to animals that are yet larger, warmer, and more perfect, as
they abound in blood, which is ever hotter and more spirituous, and
possess bodies of greater size and consistency, they require a larger,
stronger, and more fleshy heart, in order that the nutritive fluid may
be propelled with yet greater force and celerity. And further, inasmuch
as the more perfect animals require a still more perfect nutrition, and
a larger supply of native heat, in order that the aliment may be
thoroughly concocted and acquire the last degree of perfection, they
required both lungs and a second ventricle, which should force the
nutritive fluid through them.
Every animal that has lungs has therefore two ventricles to its heart,
one right, another left; and wherever there is a right, there also is
there a left ventricle; but the contrary of this does not hold good:
where there is a left there is not always a right ventricle. The left
ventricle I call that which is distinct in office, not in place from the
other, that one namely which distributes the blood to the body at large,
not to the lungs only. Hence the left ventricle seems to form the
principal part of the heart; situated in the middle, more strongly
marked, and constructed with greater care, the heart seems formed for
the sake of the left ventricle, and the right but to minister to it; for
the right neither reaches to the apex of the heart, nor is it nearly of
such strength, being three times thinner in its walls, and in some sort
jointed on to the left, (as Aristotle says;) though indeed it is of
greater capacity, inasmuch as it has not only to supply material to the
left ventricle, but likewise to furnish aliment to the lungs.
It is to be observed, however, that all this is otherwise in the embryo,
where there is not such a difference between the two ventricles; but as
in a double nut, they are nearly equal in all respects, the apex of the
right reaching to the apex of the left, so that the heart presents
itself as a sort of double-pointed cone. And this is so, because in the
fœtus, as already said, whilst the blood is not passing through the
lungs from the right to the left cavities of the heart, but flowing by
the foramen ovale and ductus arteriosus, directly from the vena cava
into the aorta, whence it is distributed to the whole body, both
ventricles have in fact the same office to perform, whence their
equality of constitution. It is only when the lungs come to be used,
and it is requisite that the passages indicated should be blocked up,
that the difference in point of strength and other things between the
two ventricles begin to be apparent: in the altered circumstances the
right has only to throw the blood through the lungs, whilst the left has
to impel it through the whole body.
There are further within the heart numerous braces, so to speak, fleshy
columns and fibrous bands, which Aristotle, in his third book on
Respiration, and the Parts of Animals, entitles nerves. These are
variously extended, and are either distinct or contained in grooves in
the walls and partition, where they occasion numerous pits or
depressions. They constitute a kind of small muscles, which are
superadded and supplementary to the heart, assisting it to execute a
more powerful and perfect contraction, and so proving subservient to the
complete expulsion of the blood. They are in some sort like the
elaborate and artful arrangement of ropes in a ship, bracing the heart
on every side as it contracts, and so enabling it more effectually and
forcibly to expel the charge of blood from its ventricles. This much is
plain, at all events, that some animals have them strongly marked,
others have them less so; and, in all that have them, they are more
numerous and stronger in the left than in the right ventricle; and
whilst some have them in the left, there are yet none present in the
right ventricle. In the human subject, again, these fleshy columns and
braces are more numerous in the left than in the right ventricle, and
they are more abundant in the ventricles than in the auricles;
occasionally, indeed, in the auricles there appear to be none present
whatsoever. In large, more muscular and hardier bodies, as of
countrymen, they are numerous; in more slender frames and in females
they are fewer.
In those animals in which the ventricles of the heart are smooth within,
and entirely without fibres or muscular bands, or anything like foveæ,
as in almost all the smaller birds, the partridge and the common fowl,
serpents, frogs, tortoises, and also fishes, for the major part, there
are no chordæ tendineæ, nor bundles of fibres, neither are there any
tricuspid valves in the ventricles.
Some animals have the right ventricle smooth internally, but the left
provided with fibrous bands, such as the goose, swan, and larger birds;
and the reason here is still the same as elsewhere: as the lungs are
spongy, and loose, and soft, no great amount of force is required to
force the blood through them; hence the right ventricle is either
without the bundles in question, or they are fewer and weaker, not so
fleshy or like muscles; those of the left ventricle, however, are both
stronger and more numerous, more fleshy and muscular, because the left
ventricle requires to be stronger, inasmuch as the blood which it
propels has to be driven through the whole body. And this, too, is the
reason why the left ventricle occupies the middle of the heart, and has
parietes three times thicker and stronger than those of the right. Hence
all animals--and among men it is not otherwise--that are endowed with
particularly strong frames, and that have large and fleshy limbs at a
great distance from the heart, have this central organ of greater
thickness, strength, and muscularity. And this is both obvious and
necessary. Those, on the contrary, that are of softer and more slender
make have the heart more flaccid, softer, and internally either sparely
or not at all fibrous. Consider farther the use of the several valves,
which are all so arranged, that the blood once received into the
ventricles of the heart shall never regurgitate, once forced into the
pulmonary artery and aorta shall not flow back upon the ventricles. When
the valves are raised and brought together they form a three cornered
line, such as is left by the bite of a leech; and the more they are
forced, the more firmly do they oppose the passage of the blood. The
tricuspid valves are placed, like gate-keepers, at the entrance into the
ventricles from the venæ cavæ and pulmonary veins, lest the blood when
most forcibly impelled should flow back; and it is for this reason that
they are not found in all animals; neither do they appear to have been
constructed with equal care in all the animals in which they are found;
in some they are more accurately fitted, in others more remissly or
carelessly contrived, and always with a view to their being closed under
a greater or a slighter force of the ventricle. In the left ventricle,
therefore, and in order that the occlusion may be the more perfect
against the greater impulse, there are only two valves, like a mitre,
and produced into an elongated cone, so that they come together and
touch to their middle; a circumstance which perhaps led Aristotle into
the error of supposing this ventricle to be double, the division taking
place transversely. For the same reason, indeed, and that the blood may
not regurgitate upon the pulmonary veins, and thus the force of the
ventricle in propelling the blood through the system at large come to be
neutralized, it is that these mitral valves excel those of the right
ventricle in size and strength, and exactness of closing. Hence, too, it
is essential that there can be no heart without a ventricle, since this
must be the source and storehouse of the blood. The same law does not
hold good in reference to the brain. For almost no genus of birds has a
ventricle in the brain, as is obvious in the goose and swan, the brains
of which nearly equal that of a rabbit in size; now rabbits have
ventricles in the brain, whilst the goose has none. In like manner,
wherever the heart has a single ventricle, there is an auricle appended,
flaccid, membranous, hollow, filled with blood; and where there are two
ventricles, there are likewise two auricles. On the other hand, however,
some animals have an auricle without any ventricle; or at all events
they have a sac analogous to an auricle; or the vein itself, dilated at
a particular part, performs pulsations, as is seen in hornets, bees, and
other insects, which certain experiments of my own enable me to
demonstrate have not only a pulse, but a respiration in that part which
is called the tail, whence it is that this part is elongated and
contracted now more rarely, now more frequently, as the creature appears
to be blown and to require a larger quantity of air. But of these
things, more in our Treatise on Respiration.
It is in like manner evident that the auricles pulsate, contract, as I
have said before, and throw the blood into the ventricles; so that
wherever there is a ventricle an auricle is necessary, not merely that
it may serve, according to the general belief, as a source and magazine
for the blood: for what were the use of its pulsations had it nothing to
do save to contain? No; the auricles are prime movers of the blood,
especially the right auricle, which is “the first to live, the last to
die;” as already said; whence they are subservient to sending the blood
into the ventricle, which, contracting incontinently, more readily and
forcibly expels the blood already in motion; just as the ball-player can
strike the ball more forcibly and further if he takes it on the rebound
than if he simply threw it. Moreover, and contrary to the general
opinion, since neither the heart nor anything else can dilate or distend
itself so as to draw aught into its cavity during the diastole, unless,
like a sponge, it has been first compressed, and as it is returning to
its primary condition; but in animals all local motion proceeds from,
and has its original in the contraction of some part: it is consequently
by the contraction of the auricles that the blood is thrown into the
ventricles, as I have already shown, and from thence, by the contraction
of the ventricles, it is propelled and distributed. Which truth
concerning local motions, and how the immediate moving organ in every
motion of an animal primarily endowed with a motive spirit (as Aristotle
has it,[98]) is contractile; and in what way the word νεῡρον is derived
from νεύω, nuto, contraho; and how Aristotle was acquainted with the
muscles, and did not unadvisedly refer all motion in animals to the
nerves, or to the contractile element, and therefore called those little
bands in the heart nerves--all this, if I am permitted to proceed in my
purpose of making a particular demonstration of the organs of motion in
animals from observations in my possession, I trust I shall be able to
make sufficiently plain.
But that we may go on with the subject we have in hand, viz., the use of
the auricles in filling the ventricles: we should expect that the more
dense and compact the heart, the thicker its parietes, the stronger and
more muscular must be the auricle to force and fill it, and _vice
versa_. Now this is actually so: in some the auricle presents itself as
a sanguinolent vesicle, as a thin membrane containing blood, as in
fishes, in which the sac that stands in lieu of the auricle, is of such
delicacy and ample capacity, that it seems to be suspended or to float
above the heart; in those fishes in which the sac is somewhat more
fleshy, as in the carp, barbel, tench, and others, it bears a wonderful
and strong resemblance to the lungs.
In some men of sturdier frame and stouter make, the right auricle is so
strong, and so curiously constructed within of bands and variously
interlacing fibres, that it seems to equal the ventricle of the heart in
other subjects; and I must say that I am astonished to find such
diversity in this particular in different individuals. It is to be
observed, however, that in the fœtus the auricles are out of all
proportion large, which is because they are present before the heart
[the ventricular portion] makes its appearance or suffices for its
office even when it has appeared, and they therefore have, as it were,
the duty of the whole heart committed to them, as has already been
demonstrated. But what I have observed in the formation of the fœtus as
before remarked (and Aristotle had already confirmed all in studying the
incubated egg,) throws the greatest light and likelihood upon the point.
Whilst the fœtus is yet in the guise of a soft worm, or, as is commonly
said, in the milk, there is a mere bloody point or pulsating vesicle, a
portion apparently of the umbilical vein, dilated at its commencement or
base; by and by, when the outline of the fœtus is distinctly indicated,
and it begins to have greater bodily consistence, the vesicle in
question having become more fleshy and stronger, and changed its
position, passes into the auricles, over or upon which the body of the
heart begins to sprout, though as yet it apparently performs no duty;
but when the fœtus is farther advanced, when the bones can be
distinguished from the soft parts, and movements take place, then it has
also a heart internately which pulsates, and, as I have said, throws
blood by either ventricle from the vena cava into the arteries.
Thus nature, ever perfect and divine, doing nothing in vain, has neither
given a heart where it was not required, nor produced it before its
office had become necessary; but by the same stages in the development
of every animal, passing through the constitutions of all, as I may say
(ovum, worm, fœtus), it acquires perfection in each. These points will
be found elsewhere confirmed by numerous observations on the formation
of the fœtus.
Finally, it was not without good grounds that Hippocrates, in his book,
‘De Corde,’ intitles it a muscle; as its action is the same, so is its
function, viz., to contract and move something else, in this case, the
charge of blood.
Farther, as in muscles at large, so can we infer the action and use of
the heart from the arrangement of its fibres and its general structure.
All anatomists admit with Galen that the body of the heart is made up of
various courses of fibres running straight, obliquely, and transversely,
with reference to one another; but in a heart which has been boiled the
arrangement of the fibres is seen to be different: all the fibres in the
parietes and septum are circular, as in the sphincters; those, again,
which are in the columnæ extend lengthwise, and are oblique
longitudinally; and so it comes to pass, that when all the fibres
contract simultaneously, the apex of the cone is pulled towards its base
by the columnæ, the walls are drawn circularly together into a globe,
the whole heart in short is contracted, and the ventricles narrowed; it
is therefore impossible not to perceive that, as the action of the organ
is so plainly contraction, its function is to propel the blood into the
arteries.
Nor are we the less to agree with Aristotle in regard to the sovereignty
of the heart; nor are we to inquire whether it receives sense and motion
from the brain? whether blood from the liver? whether it be the origin
of the veins and of the blood? and more of the same description. They
who affirm these propositions against Aristotle, overlook, or do not
rightly understand the principal argument, to the effect that the heart
is the first part which exists, and that it contains within itself
blood, life, sensation, motion, before either the brain or the liver
were in being, or had appeared distinctly, or, at all events, before
they could perform any function. The heart, ready furnished with its
proper organs of motion, like a kind of internal creature, is of a date
anterior to the body: first formed, nature willed that it should
afterwards fashion, nourish, preserve, complete the entire animal, as
its work and dwelling place: the heart, like the prince in a kingdom, in
whose hands lie the chief and highest authority, rules over all; it is
the original and foundation from which all power is derived, on which
all power depends in the animal body.
And many things having reference to the arteries farther illustrate and
confirm this truth. Why does not the arteria venosa pulsate, seeing that
it is numbered among the arteries? Or wherefore is there a pulse in the
vena arteriosa? Because the pulse of the arteries is derived from the
impulse of the blood. Why does an artery differ so much from a vein in
the thickness and strength of its coats? Because it sustains the shock
of the impelling heart and streaming blood. Hence, as perfect nature
does nothing in vain, and suffices under all circumstances, we find that
the nearer the arteries are to the heart, the more do they differ from
the veins in structure; here they are both stronger and more
ligamentous, whilst in extreme parts of the body, such as the feet and
hands, the brain, the mesentery, and the testicles, the two orders of
vessels are so much alike that it is impossible to distinguish between
them with the eye. Now this is for the following very sufficient
reasons: for the more remote vessels are from the heart, with so much
the less force are they impinged upon by the stroke of the heart, which
is broken by the great distance at which it is given. Add to this, that
the impulse of the heart exerted upon the mass of blood, which must
needs fill the trunks and branches of the arteries, is diverted,
divided, as it were, and diminished at every subdivision; so that the
ultimate capillary divisions of the arteries look like veins, and this
not merely in constitution but in function; for they have either no
perceptible pulse, or they rarely exhibit one, and never save where the
heart beats more violently than wont, or at a part where the minute
vessel is more dilated or open than elsewhere. Hence it happens that at
times we are aware of a pulse in the teeth, in inflammatory tumours, and
in the fingers; at another time we feel nothing of the sort. Hence, too,
by this single symptom I have ascertained for certain that young
persons, whose pulses are naturally rapid, were labouring under fever;
in like manner, on compressing the fingers in youthful and delicate
subjects during a febrile paroxysm, I have readily perceived the pulse
there. On the other hand, when the heart pulsates more languidly, it is
often impossible to feel the pulse not merely in the fingers, but at the
wrist, and even at the temple; this is the case in persons afflicted
with lipothymiæ and asphyxia, and hysterical symptoms, as also in
persons of very weak constitution and in the moribund.
And here surgeons are to be advised that, when the blood escapes with
force in the amputation of limbs, in the removal of tumours, and in
wounds, it constantly comes from an artery; not always per saltum,
however, because the smaller arteries do not pulsate, especially if a
tourniquet has been applied.
And then the reason is the same wherefore the pulmonary artery has not
only the structure of an artery, but wherefore it does not differ so
widely in the thickness of its tunics from the veins as the aorta: the
aorta sustains a more powerful shock from the left ventricle than the
pulmonary artery does from the right; and the tunics of this last vessel
are thinner and softer than those of the aorta in the same proportion as
the walls of the right ventricle of the heart are weaker and thinner
than those of the left ventricle; and in like manner, in the same degree
in which the lungs are softer and laxer in structure than the flesh and
other constituents of the body at large, do the tunics of the branches
of the pulmonary artery differ from the tunics of the vessels derived
from the aorta. And the same proportion in these several particulars is
universally preserved. The more muscular and powerful men are, the
firmer their flesh, the stronger, thicker, denser, and more fibrous
their heart, in the same proportion are the auricles and arteries in all
respects thicker, closer, and stronger. And again, and on the other
hand, in those animals the ventricles of whose heart are smooth within,
without villi or valves, and the walls of which are thinner, as in
fishes, serpents, birds, and very many genera of animals, in all of them
the arteries differ little or nothing in the thickness of their coats
from the veins.
Farther, the reason why the lungs have such ample vessels, both arteries
and veins, (for the capacity of the pulmonary veins exceeds that of both
the crural and jugular vessels,) and why they contain so large a
quantity of blood, as by experience and ocular inspection we know they
do, admonished of the fact indeed by Aristotle, and not led into error
by the appearances found in animals which have been bled to death,--is,
because the blood has its fountain, and storehouse, and the workshop of
its last perfection in the heart and lungs. Why, in the same way we find
in the course of our anatomical dissections the arteria venosa and left
ventricle so full of blood, of the same black colour and clotted
character, too, as that with which the right ventricle and pulmonary
artery are filled, inasmuch as the blood is incessantly passing from one
side of the heart to the other through the lungs. Wherefore, in fine,
the pulmonary artery or vena arteriosa has the constitution of an
artery, and the pulmonary veins or arteriæ venosæ have the structure of
veins; because, in sooth, in function and constitution, and everything
else, the first is an artery, the others are veins, in opposition to
what is commonly believed; and why the pulmonary artery has so large an
orifice, because it transports much more blood than is requisite for the
nutrition of the lungs.
All these appearances, and many others, to be noted in the course of
dissection, if rightly weighed, seem clearly to illustrate and fully to
confirm the truth contended for throughout these pages, and at the same
time to stand in opposition to the vulgar opinion; for it would be very
difficult to explain in any other way to what purpose all is constructed
and arranged as we have seen it to be.
AN ANATOMICAL DISQUISITION
ON THE
CIRCULATION OF THE BLOOD.
TO
JOHN RIOLAN, JUN., OF PARIS;
A MOST SKILFUL PHYSICIAN; THE CORYPHÆUS OF ANATOMISTS; REGIUS
PROFESSOR OF ANATOMY AND BOTANY IN THE UNIVERSITY OF PARIS;
DEAN OF THE SAME UNIVERSITY; AND FIRST PHYSICIAN TO
THE QUEEN, MOTHER OF LOUIS XIII.
BY WILLIAM HARVEY, AN ENGLISHMAN,
PROFESSOR OF ANATOMY AND SURGERY IN THE ROYAL COLLEGE OF
PHYSICIANS OF LONDON; AND PRINCIPAL PHYSICIAN TO
HIS MOST SERENE MAJESTY THE KING.
CAMBRIDGE, 1649.
THE FIRST ANATOMICAL DISQUISITION ON THE CIRCULATION OF THE BLOOD,
ADDRESSED TO JO. RIOLAN.
Some few months ago there appeared a small anatomical and pathological
work from the pen of the celebrated Riolanus, for which, as sent to me
by the author himself, I return him my grateful thanks.[99] I also
congratulate this author on the highly laudable undertaking in which he
has engaged. To demonstrate the seats of all diseases is a task that can
only be achieved under favour of the highest abilities; for surely he
enters on a difficult province who proposes to bring under the
cognizance of the eyes those diseases which almost escape the keenest
understanding. But such efforts become the prince of anatomists; for
there is no science which does not spring from preexisting knowledge,
and no certain and definite idea which has not derived its origin from
the senses. Induced therefore by the subject itself, and the example of
so distinguished an individual, which makes me think lightly of the
labour, I also intend putting to press my Medical Anatomy, or Anatomy in
its Application to Medicine. Not with the purpose, like Riolanus, of
indicating the seats of diseases from the bodies of healthy subjects,
and discussing the several diseases that make their appearance there,
according to the views which others have entertained of them; but that I
may relate from the many dissections I have made of the bodies of
persons diseased, worn out by serious and strange affections, how and in
what way the internal organs were changed in their situation, size,
structure, figure, consistency, and other sensible qualities, from their
natural forms and appearances, such as they are usually described by
anatomists; and in what various and remarkable ways they were affected.
For even as the dissection of healthy and well-constituted bodies
contributes essentially to the advancement of philosophy and sound
physiology, so does the inspection of diseased and cachectic subjects
powerfully assist philosophical pathology. And, indeed, the
physiological consideration of the things which are according to nature
is to be first undertaken by medical men; since that which is in
conformity with nature is right, and serves as a rule both to itself and
to that which is amiss; by the light it sheds, too, aberrations and
affections against nature are defined; pathology then stands out more
clearly; and from pathology the use and art of healing, as well as
occasions for the discovery of many new remedies, are perceived. Nor
could any one readily imagine how extensively internal organs are
altered in diseases, especially chronic diseases, and what monstrosities
among internal parts these diseases engender. So that I venture to say,
that the examination of a single body of one who has died of tabes or
some other disease of long standing, or poisonous nature, is of more
service to medicine than the dissection of the bodies of ten men who
have been hanged.
I would not have it supposed by this that I in any way disapprove of the
purpose of Riolanus, that learned and skilful anatomist; on the
contrary, I think it deserving of the highest praise, as likely to be
extremely useful to medicine, inasmuch as it illustrates the
physiological branch of this science; but I have thought that it would
scarcely turn out less profitable to the art of healing, did I place
before the eyes of my readers not only the places, but the affections of
these places, illustrating them as I proceed with observations, and
recording the results of my experience derived from my numerous
dissections.
But it is imperative on me first to dispose of those observations
contained in the work referred to, which bear upon the circulation of
the blood as discovered by me, and which seem to require especial notice
at my hands. For the judgment of such a man, who is indeed the prince
and leader of all the anatomists of the present age, in such a matter,
is not to be lightly esteemed, but is rather to be held of greater
weight and authority, either for praise or blame, than the commendations
or censure of all the world besides.
Riolanus, then, admits our motion of the blood in animals,[100] and
falls in with our conclusions in regard to the circulation; yet not
entirely and avowedly; for he says[101] that the blood contained in the
vena portæ does not circulate like that in the vena cava; and again he
states[102] that there is some blood which circulates, and that the
circulatory vessels are the aorta and vena cava; but then he denies that
the continuations of these trunks have any circulation, “because the
blood is effused into all the parts of the second and third regions,
where it remains for purposes of nutrition; nor does it return to any
greater vessels, unless forcibly drawn back when there is a great lack
of blood in the main channels, or driven by a fit of passion when it
flows to the greater circulatory vessels;” and shortly afterwards:
“thus, as the blood of the veins naturally ascends incessantly or
returns to the heart, so the blood of the arteries descends or departs
from the heart; still, if the smaller veins of the arms and legs be
empty, the blood filling the empty channels in succession, may descend
in the veins, as I have clearly shown,” he says, “against Harvey and
Walæus.” And as the authority of Galen and daily experience confirm the
anastomoses of the arteries and veins, and the necessity of the
circulation of the blood, “you perceive,” he continues, “how the
circulation is effected, without any perturbation or confusion of fluids
and the destruction of the ancient system of medicine.”
These words explain the motives by which this illustrious anatomist was
actuated when he was led partly to admit, partly to deny the circulation
of the blood; and why he only ventures on an undecided and inconclusive
opinion of the subject; his fear is lest it destroy the ancient
medicine. Not yielding implicitly to the truth, which it appears he
could not help seeing, but rather guided by caution, he fears speaking
plainly out, lest he offend the ancient physic, or perhaps seem to
retract the physiological doctrines he supports in his Anthropology. The
circulation of the blood does not shake, but much rather confirms the
ancient medicine; though it runs counter to the physiology of
physicians, and their speculations upon natural subjects, and opposes
the anatomical doctrine of the use and action of the heart and lungs,
and rest of the viscera. That this is so shall readily be made to
appear, both from his own words and avowal, and partly also from what I
shall supply; viz., that the whole of the blood, wherever it be in the
living body, moves and changes its place, not merely that which is in
the larger vessels and their continuations, but that also which is in
their minute subdivisions, and which is contained in the pores or
interstices of every part; that it flows from and back to the heart
ceaselessly and without pause, and could not pause for ever so short a
time without detriment, although I admit that occasionally, and in some
places, its motion is quicker or slower.[103]
In the first place, then, our learned anatomist only denies that the
contents of the branches in continuation of the vena portæ circulate;
but he could neither oppose nor deny this, did he not conceal from
himself the force of his own arguments; for he says in his Third Book,
chap. viii, “If the heart at each pulsation admits a drop of blood which
it throws into the aorta, and in the course of an hour makes two
thousand beats, it is a necessary consequence that the quantity of blood
transmitted must be great.” He is farther forced to admit as much in
reference to the mesentery, when he sees that far more than single drops
of blood are sent into the cœliac and mesenteric arteries at each
pulsation; so that there must either be some outlet for the fluid, of
magnitude commensurate with its quantity, or the branches of the vena
portæ must give way. Nor can the explanation that is had recourse to
with a view of meeting the difficulty, viz., that the blood of the
mesentery ebbs and flows by the same channels, after the manner of
Euripus, be received as either probable or possible. Neither can the
reflux from the mesentery be effected by those passages and that system
of translation, by which he will have it to disgorge itself into the
aorta; this were against the force of the existing current, and by a
contrary motion; nor can anything like pause or alternation be admitted,
where there is very certainly an incessant influx: the blood sent into
the mesentery must as inevitably go elsewhere as that which is poured
into the heart. And this is obvious; were it otherwise, indeed,
everything like a circulation might be overturned upon the same showing
and by the same subterfuge; it might just as well be said that the blood
contained in the left ventricle of the heart is propelled into the aorta
during the systole, and flows back to it during the diastole, the aorta
disgorging itself into the ventricle, precisely as the ventricle has
disgorged itself into the aorta. There would thus be circulation neither
in the heart nor in the mesentery, but an alternate flux and reflux,--a
useless labour, as it seems. If, therefore, and for the reason assigned
and approved by him, a circulation through the heart be argued for as a
thing necessary, the argument has precisely the same force when applied
to the mesentery: if there be no circulation in the mesentery, neither
is there any in the heart; for both affirmations, this in reference to
the heart, that in reference to the mesentery, merely changing the
words, stand or fall together, by force of the very same arguments.
He says: “The sigmoid valves prevent regurgitation into the heart; but
there are no valves in the mesentery.” To this I reply, that the thing
is not so; for there is a valve in the splenic vein, and sometimes also
in other veins. And besides, valves are not met with universally in
veins; there are few or none in the deep-seated veins of the
extremities, but many in the subcutaneous branches. For where the blood
is flowing naturally from smaller into greater branches, into which it
is disposed to enter, the pressure of the circumjacent muscles is
enough, and more than enough to prevent all retrograde movement, and it
is forced on where the way lies open; in such circumstances, what use
were there for valves? But the quantity of blood that is forced into the
mesentery by each stroke of the heart, may be estimated in the same way
as you estimate the quantity impelled into the hand when you bind a
ligature with medium tightness about the wrist: if in so many beats the
vessels of the hand become distended, and the whole extremity swells,
you will find, that much more than a single drop of blood has entered
with each pulse, and which cannot return, but must remain to fill the
hand and increase its size. But analogy permits us to say, that the same
thing takes place in reference to the mesentery and its vessels, in an
equal degree at least, if not in a greater degree, seeing that the
vessels of the mesentery are considerably larger than those of the
carpus. And if any one will but think on the difficulty that is
experienced with all the aid supplied by compresses, bandages, and a
multiplied apparatus, in restraining the flow of blood from the smallest
artery when wounded, with what force it overcomes all obstacles and
soaks through the whole apparatus, he will scarcely, I imagine, think it
likely that there can be any retrograde motion against such an impulse
and influx of blood, any retrograde force to meet and overcome a direct
force of such power. Turning over these things in his mind, I say, no
one will ever be brought to believe that the blood from the branches of
the vena portæ can possibly make its way by the same channels against an
influx by the artery of such impetuosity and force, and so unload the
mesentery.
Moreover, if the learned anatomist does not think that the blood is
moved and changed by a circular motion, but that the same fluid always
stagnates in the channels of the mesentery, he appears to suppose that
there are two descriptions of blood, serving different uses and ends;
that the blood of the vena portæ, and that of the vena cava are
dissimilar in constitution, seeing that the one requires a circulation
for its preservation, the other requires nothing of the kind; which
neither appears on the face of the thing, nor is its truth demonstrated
by him. Our author then refers to “A fourth order of mesenteric vessels,
the lacteal vessels, discovered by Asellius;0”[104] and having mentioned
these, he seems to infer that they extract all the nutriment from the
intestines, and transfer this to the liver, the workshop of the blood,
whence, having been concocted and changed into blood, (so he says in his
third book, chapter the 8th), the blood is transferred from the liver to
the right ventricle of the heart. “Which things premised,” he
continues,[105] “all the difficulties which were formerly experienced in
regard to the distribution of the chyle and blood by the same channel
come to an end; for the lacteal veins carry the chyle to the liver, and
as these canals are distinct, so may they be severally obstructed.” But
truly I would here ask: how this milky fluid can be poured into and pass
through the liver, and how from thence gain the vena cava and the
ventricle of the heart? when our author denies that the blood of the
vena portæ passes through the liver, and that so a circulation is
established. I pause for a reply. I would fain know how such a thing can
be shown to be probable; especially when the blood appears to be both
more spirituous or subtile and penetrating than the chyle or milk
contained in these lacteal vessels, and is further impelled by the
pulsations of the arteries that it may find a passage by other channels.
Our learned author mentions a certain tract of his on the Circulation of
the Blood: I wish I could obtain a sight of it; perhaps I might retract.
But had the learned writer been so disposed, I do not see but that
having admitted the circular motion of the blood,[106] all the
difficulties which were formerly felt in connexion with the distribution
of the chyle and the blood by the same channels are brought to an
equally satisfactory solution; so much so indeed that there would be no
necessity for inquiring after or laying down any separate vessels for
the chyle. Even as the umbilical veins absorb the nutritive juices from
the fluids of the egg and transport them for the nutrition and growth of
the chick, in its embryo state, so do the meseraic veins suck up the
chyle from the intestines and transfer it to the liver; and why should
we not maintain that they perform the same office in the adult? For all
the mooted difficulties vanish when we cease to suppose two contrary
motions in the same vessels, and admit but one and the same continuous
motion in the mesenteric vessels from the intestines to the liver.
I shall elsewhere state my views of the lacteal veins when I treat of
the milk found in different parts of new-born animals, especially of the
human subject; for it is met with in the mesentery and all its glands,
in the thymus, in the axillæ, also in the breasts of infants. This milk
the midwifes are in the habit of pressing out, for the health, as they
believe, of the infants. But it has pleased the learned Riolanus, not
only to take away circulation from the blood contained in the mesentery;
he affirms that neither do the vessels in continuation of the vena cava,
nor the arteries, nor any of the parts of the second and third regions,
admit of circulation, so that he entitles and enumerates as circulating
vessels the vena cava and aorta only. For this he appears to me to give
a very indifferent reason:[107] “The blood,” he says, “effused into all
the parts of the second and third regions, remains there for their
nutrition; nor does it return to the great vessels, unless forcibly
drawn back by an extreme dearth of blood in the great vessels, nor,
unless carried by an impulse, does it flow to the circulatory vessels.”
That so much of the blood must remain as is appropriated to the
nutrition of the tissues, is matter of necessity; for it cannot nourish
unless it be assimilated and become coherent, and form substance in lieu
of that which is lost; but that the whole of the blood which flows into
a part should there remain, in order that so small a portion should
undergo transformation, is nowise necessary; for no part uses so much
blood for its nutrition as is contained in its arteries, veins, and
interstices. Nor because the blood is continually coming and going is it
necessary to suppose that it leaves nothing for nutriment behind it.
Consequently it is by no means necessary that the whole remain in order
that nutrition be effected. But our learned author, in the same book,
where he affirms so much, appears almost everywhere else to assert the
contrary. In that paragraph especially where he describes the
circulation in the brain, he says: “And the brain by means of the
circulation sends back blood to the heart, and thus refrigerates the
organ.” And in the same way are all the more remote parts said to
refrigerate the heart; thus in fevers, when the præcordia are scorched
and burn with febrile heat, patients baring their limbs and casting off
the bedclothes, seek to cool their heart; and the blood generally,
tempered and cooled down, as our learned author states it to be with
reference to the brain in particular, returns by the veins and
refrigerates the heart. Our author, therefore, appears to insinuate a
certain necessity for a circulation from every part, as well as from the
brain, in opposition to what he had before said in very precise terms.
But then he cautiously and ambiguously asserts, that the blood does not
return from the parts composing the second and third regions, unless, as
he says, it is drawn by force, and through a signal deficiency of blood
in the larger vessels, &c., which is most true if these words be rightly
understood; for by the larger vessels, in which the deficiency is said
to cause the reflux, I think he must be held to mean the veins not the
arteries; for the arteries are never emptied, save into the veins or
interstices of parts, but are incessantly filled by the strokes of the
heart; but in the vena cava and other returning channels, in which the
blood glides rapidly on, hastening to the heart, there would speedily
be a great deficiency of blood did not every part incessantly restore
the blood that is incessantly poured into it. Add to this, that by the
impulse of the blood which is forced with each stroke into every part of
the second and third regions, that which is contained in the pores or
interstices is urged into the smaller veins, from which it passes into
larger vessels, its motion assisted besides by the motion and pressure
of circumjacent parts; for from every containing thing compressed and
constringed, contained matters are forced out. And thus it is that by
the motions of the muscles and extremities, the blood contained in the
minor vessels is forced onwards and delivered into the larger trunks.
But that the blood is incessantly driven from the arteries into every
part of the body, there gives a pulse and never flows back in these
channels, cannot be doubted, if it be admitted that with each pulse of
the heart all the arteries are simultaneously distended by the blood
sent into them; and as our learned author himself allows that the
diastole of the arteries is occasioned by the systole of the heart, and
that the blood once out of the heart can never get back into the
ventricles by reason of the opposing valves; if I say, our learned
author believes that these things are so, it will be as manifestly true
with regard to the force and impulse by which the blood contained in the
vessels is propelled into every part of every region of the body. For
wheresoever the arteries pulsate, so far must the impulse and influx
extend, and therefore is the impulse felt in every part of each several
region; for there is a pulse everywhere, to the very points of the
fingers and under the nails, nor is there any part of the body where the
shooting pain that accompanies each pulse of the artery, and the effort
made to effect a solution of the continuity is not experienced when it
is the seat of a phlegmon or furuncle.
But, further, that the blood contained in the pores of the living
tissues returns to the heart, is manifest from what we observe in the
hands and feet. For we frequently see the hands and feet, in young
persons especially, during severe weather, become so cold that to the
touch they feel like ice, and they are so benumbed and stiffened that
they seem scarcely to retain a trace of sensibility or to be capable of
any motion; still are they all the while surcharged with blood, and look
red or livid. Yet can the extremities be warmed in no way, save by
circulation; the chilled blood, which has lost its spirit and heat,
being driven out, and fresh, warm, and vivified blood flowing in by the
arteries in its stead, which fresh blood cherishes and warms the parts,
and restores to them sense and motion; nor could the extremities be
restored by the warmth of a fire or other external heat, any more than
those of a dead body could be so recovered: they are only brought to
life again, as it were, by an influx of internal warmth. And this indeed
is the principal use and end of the circulation; it is that for which
the blood is sent on its ceaseless course, and to exert its influence
continually in its circuit, to wit, that all parts dependent on the
primary innate heat may be retained alive, in their state of vital and
vegetative being, and apt to perform their functions; whilst, to use the
language of physiologists, they are sustained and actuated by the
inflowing heat and vital spirits. Thus, by the aid of two extremes, viz.
cold and heat, is the temperature of the animal body retained at its
mean. For as the air inspired tempers the too great heat of the blood in
the lungs and centre of the body, and effects the expulsion of
suffocating fumes, so in its turn does the hot blood, thrown by the
arteries into all parts of the body, cherish and nourish and keep them
in life, defending them from extinction through the power of external
cold.
It would, therefore, be in some sort unfair and extraordinary did not
every particle composing the body enjoy the advantages of the
circulation and transmutation of the blood; the ends for which the
circulation was mainly established by nature would no longer be
effected. To conclude then: you see how circulation may be accomplished
without confusion or admixture of humours, through the whole body, and
each of its individual parts, in the smaller as well as in the larger
vessels; and all as matter of necessity and for the general advantage;
without circulation, indeed, there would be no restoration of chilled
and exhausted parts, no continuance of these in life; since it is
apparent enough that the whole influence of the preservative heat comes
by the arteries, and is the work of the circulation.
It, therefore, appears to me that the learned Riolanus speaks rather
expediently than truly, when in his Enchiridion he denies a circulation
to certain parts; it would seem as though he had wished to please the
mass, and oppose none; to have written with such a bias rather than
rigidly and in behalf of the simple truth. This is also apparent when he
would have the blood to make its way into the left ventricle through the
septum of the heart, by certain invisible and unknown passages, rather
than through those ample and abundantly pervious channels, the pulmonary
vessels, furnished with valves, opposing all reflux or regurgitation. He
informs us that he has elsewhere discussed the reasons of the
impossibility or inconvenience of this: I much desire to see his
disquisition. It would be extraordinary, indeed, were the aorta and
pulmonary artery, with the same dimensions, properties, and structure,
not to have the same functions. But it would be more wonderful still
were the whole tide of the blood to reach the left ventricle by a set of
inscrutable passages of the septum, a tide which, in quantity must
correspond, first to the influx from the vena cava into the right side
of the heart, and next to the efflux from the left, both of which
require such ample conduits. But our author has adduced these matters
inconsistently, for he has established the lungs as an emunctory or
passage from the heart;[108] and he says: “The lung is affected by the
blood which passes through it, the sordes flowing along with the blood.”
And, again: “The lungs receive injury from distempered and
ill-conditioned viscera; these deliver an impure blood to the heart,
which it cannot correct except by multiplied circulations.” In the same
place, he further proceeds, whilst speaking against Galen of
bloodletting in peripneumonia and the communication of the veins: “Were
it true that the blood naturally passed from the right ventricle of the
heart to the lungs, that it might be carried into the left ventricle and
from thence into the aorta; and were the circulation of the blood
admitted, who does not see that in affections of the lungs the blood
would flow to them in larger quantity and would oppress them, unless it
were taken away, first, freely, and then in repeated smaller quantities
in order to relieve them, which indeed was the advice of Hippocrates,
who, in affections of the lungs takes away blood from every part--the
head, nose, tongue, arms and feet, in order that its quantity may be
diminished and a diversion effected from the lungs; he takes away blood
till the body is almost bloodless. Now admitting the circulation, the
lungs are most readily depleted by opening a vein; but rejecting it, I
do not see how any revulsion of the blood can be accomplished by this
means; for did it flow back by the pulmonary artery upon the right
ventricle, the sigmoid valves would oppose its entrance, and any escape
from the right ventricle into the vena cava is prevented by the
tricuspid valves. The blood, therefore, is soon exhausted when a vein is
opened in the arm or foot, if we admit the circulation; and the opinion
of Fernelius is at the same time upset by this admission, viz. that in
affections of the lungs it is better to bleed from the right than the
left arm; because the blood cannot flow backwards into the vena cava
unless the two barriers situated in the heart be first broken down.”
He adds yet further in the same place:[109] “If the circulation of the
blood be admitted, and it be acknowledged that this fluid generally
passes through the lungs, not through the middle partition of the heart,
a double circulation becomes requisite; one effected through the lungs,
in the course of which the blood quitting the right ventricle of the
heart passes through the lungs in order that it may arrive at the left
ventricle; leaving the heart on the one hand, therefore, the blood
speedily returns to it again; another and longer circulation proceeding
from the left ventricle of the heart performs the circuit of the whole
body by the arteries, and by the veins returns to the right side of the
heart.”
The learned anatomist might here have added a third and extremely short
circulation, viz.--from the left to the right ventricle of the heart,
with that blood which courses through the coronary arteries and veins,
and by their ramifications is distributed to the body, walls, and septum
of the heart.
“He who admits one circulation,” proceeds our author, “cannot repudiate
the other;” and he might, as it appears, have added, “the third.” For
why should the coronary arteries of the heart pulsate, if it were not to
force on the blood by their pulsations? and why should there be coronary
veins, the end and office of all veins being to receive the blood
brought by the arteries, were it not to deliver and discharge the blood
sent into the substance of the heart? In this consideration let it be
remembered that a valve is very commonly found at the orifice of the
coronary vein, as our learned author himself admits,[110] preventing all
ingress, but offering no obstacle to the egress of the blood. It
therefore seems that he cannot do otherwise than admit this third
circulation, who acknowledges a general circulation through the body,
and that the blood also passes through the lungs and the brain.[111]
Nor, indeed, can he deny a similar circulation to every other part of
every other region. The blood flowing in under the influence of the
arterial pulse, and returning by the veins, every particle of the body
has its circulation.
From the words of our learned writer quoted above, consequently, his
opinion may be gathered both of the general circulation, and then of the
circulation through the lungs and the several parts of the body; for he
who admits the first, manifestly cannot refuse to acknowledge the
others. How indeed could he who has repeatedly asserted a circulation
through the general system and the greater vessels, deny a circulation
in the branches continuous with these vessels, or in the several parts
of the second and third regions? as if all the veins, and those he calls
greater circulatory vessels, were not enumerated by every anatomist, and
by himself, as being within the second region of the body. Is it
possible that there can be a circulation which is universal, and which
yet does not extend through every part? Where he denies it, then, he
does so hesitatingly, and vaccillates between negations, giving us mere
words. Where he asserts the circulation, on the contrary, he speaks out
heartily, and gives sufficient reasons, as becomes a philosopher; and
then, when he relies on this opinion in a particular instance, he
delivers himself like an experienced physician and honest man, and, in
opposition to Galen and his favorite Fernelius, advises bloodletting as
the chief remedy in dangerous diseases of the lungs.
No learned man and Christian, having doubts in such a case, would have
recommended his experience to posterity, to the imminent risk, and even
loss of human life; neither would he without very sufficient reasons,
have repudiated the authority of Galen and Fernelius, which has usually
such weight with him. Whatever he has denied in the circulation of the
blood, therefore, whether with reference to the mesentery or any other
part, and with an eye to the lacteal veins or the ancient system of
physic, or any other consideration, must be ascribed to his courtesy and
modesty, and is to be excused.
Thus far, I think, it appears plain enough, from the very words and
arguments of our author, that there is a circulation everywhere; that
the blood, wherever it is, changes its place, and by the veins returns
to the heart; so that our learned author seems to be of the same opinion
as myself. It would therefore be labour in vain, did I here quote at
greater length the various reasons which I have consigned in my work on
the Motion of the Blood, in confirmation of my opinions, and which are
derived from the structure of the vessels, the position of the valves,
and other matters of experience and observation; and this the more, as I
have not yet seen the treatise on the Circulation of the Blood of the
learned writer; nor, indeed, have I yet met with a single argument of
his, or more than his simple negation, which would lead me to see
wherefore he should reject a circulation which he admits as universal,
in certain parts, regions, and vessels.
It is true that by way of subterfuge he has recourse to an anastomosis
of the vessels on the authority of Galen, and the evidence of daily
experience. But so distinguished a personage, an anatomist so expert, so
inquisitive, and careful, should first have shown anastomoses between
the larger arteries and larger veins, and these, both obvious and ample,
having mouths in relation with such a torrent as is constituted by the
whole mass of the blood, and larger than the capacity of the continuous
branches, (from which he takes away all circulation,) before he had
rejected those that are familiarly known, that are more likely and more
open; he ought to have clearly shown us where these anastomoses are, and
how they are fashioned, whether they be adapted only to permit the
access of the blood into the veins, and not to allow of its
regurgitation, in the same way as we see the ureters connected with the
urinary bladder, or in what other manner things are contrived. But--and
here I speak over boldly perhaps--neither our learned author himself,
nor Galen, nor any experience, has ever succeeded in making such
anastomoses as he imagines, sensible to the eye.
I have myself pursued this subject of the anastomosis with all the
diligence I could command, and have given not a little both of time and
labour to the inquiry; but I have never succeeded in tracing any
connexion between arteries and veins by a direct anastomosis of their
orifices. I would gladly learn of those who give so much to Galen, how
they dare swear to what he says. Neither in the liver, spleen, lungs,
kidneys, nor any other viscus, is such a thing as an anastomosis to be
seen; and by boiling, I have rendered the whole parenchyma of these
organs so friable that it could be shaken like dust from the fibres, or
picked away with a needle, until I could trace the fibres of every
subdivision, and see every capillary filament distinctly. I can
therefore boldly affirm, that there is neither any anastomosis of the
vena portæ with the cava, of the arteries with the veins, or of the
capillary ramifications of the biliary ducts, which can be traced
through the entire liver, with the veins. This alone may be observed in
the recent liver: all the branches of the vena cava ramifying through
the convexity of the liver, have their tunics pierced with an infinity
of minute holes, as is a sieve, and are fashioned to receive the blood
in its descent. The branches of the porta are not so constituted, but
simply spread out in subdivisions; and the distribution of these two
vessels is such, that whilst the one runs upon the convexity, the other
proceeds along the concavity of the liver to its outer margin, and all
the while without anastomosing.
In three places only do I find anything that can be held equivalent to
an anastomosis. From the carotids, as they are creeping over the base of
the brain, numerous interlaced fibres arise, which afterwards form the
choroid plexus, and passing through the lateral ventricles, finally
unite and terminate in the third sinus, which performs the office of a
vein. In the spermatic vessels, commonly called vasa præparantia,
certain minute arteries proceeding from the great artery adhere to the
venæ præparantes, which they accompany, and are at length taken in and
included within their coats, in such a way that they seem to have a
common ending, so that where they terminate on the upper portion of the
testis, on that cone-shaped process called the corpus varicosum et
pampiniforme, it is altogether uncertain whether we are to regard their
terminations as veins, or as arteries, or as both. In the same way are
the ultimate ramifications of the arteries which run to the umbilical
vein, lost in the tunics of this vessel.
What doubt can there be, if by such channels the great arteries,
distended by the stream of blood sent into them, are relieved of so
great and obvious a torrent, but that nature would not have denied
distinct and visible passages, vortices, and estuaries, had she intended
to divert the whole current of the blood, and had wished in this way to
deprive the lesser branches and the solid parts of all the benefit of
the influx of that fluid?
Finally, I shall quote this single experiment, which appears to me
sufficient to clear up all doubts about the anastomoses, and their uses,
if any exist, and to set at rest the question of a passage of the blood
from the veins to the arteries, by any special channels, or by
regurgitation.
Having laid open the thorax of an animal, and tied the vena cava near
the heart, so that nothing shall pass from that vessel into its
cavities, and immediately afterwards, having divided the carotid
arteries on both sides, the jugular veins being left untouched; if the
arteries be now perceived to become empty but not the veins, I think it
will be manifest that the blood does nowhere pass from the veins into
the arteries except through the ventricles of the heart. Were it not so,
as observed by Galen, we should see the veins as well as the arteries
emptied in a very short time, by the efflux from their corresponding
arteries.
For what further remains, oh Riolanus! I congratulate both myself and
you: myself, for the opinion with which you have graced my circulation;
and you, for your learned, polished, and terse production, than which
nothing more elegant can be imagined. For the favour you have done me in
sending me this work, I feel most grateful, and I would gladly, as in
duty bound, proclaim my sense of its merits, but I confess myself
unequal to the task; for I know that the Enchiridion bearing the name of
Riolanus inscribed upon it, has thereby more of honour conferred upon it
than it can derive from any praise of mine, which nevertheless I would
yield without reserve. The famous book will live for ever; and when
marble shall have mouldered, will proclaim to posterity the glory that
belongs to your name. You have most happily conjoined anatomy with
pathology, and have greatly enriched the subject with a new and most
useful osteology. Proceed in your worthy career, most illustrious
Riolanus, and love him who wishes that you may enjoy both happiness and
length of days, and that all your admirable works may conduce to your
eternal fame.
WILLIAM HARVEY.
A
SECOND DISQUISITION TO JOHN RIOLAN, JUN.,
IN WHICH
MANY OBJECTIONS
TO THE
CIRCULATION OF THE BLOOD
ARE REFUTED.
A SECOND DISQUISITION TO JOHN RIOLAN.
It is now many years, most learned Riolanus, since, with the aid of the
press, I published a portion of my work. But scarce a day, scarce an
hour, has passed since the birth-day of the Circulation of the blood,
that I have not heard something for good or for evil said of this my
discovery. Some abuse it as a feeble infant, and yet unworthy to have
seen the light; others, again, think the bantling deserves to be
cherished and cared for; these oppose it with much ado, those patronize
it with abundant commendation; one party holds that I have completely
demonstrated the circulation of the blood by experiment, observation,
and ocular inspection, against all force and array of argument; another
thinks it scarcely yet sufficiently illustrated--not yet cleared of all
objections. There are some, too, who say that I have shown a
vainglorious love of vivisections, and who scoff at and deride the
introduction of frogs and serpents, flies, and others of the lower
animals upon the scene, as a piece of puerile levity, not even
refraining from opprobrious epithets.
To return evil speaking with evil speaking, however, I hold to be
unworthy in a philosopher and searcher after truth; I believe that I
shall do better and more advisedly if I meet so many indications of ill
breeding with the light of faithful and conclusive observation. It
cannot be helped that dogs bark and vomit their foul stomachs, or that
cynics should be numbered among philosophers; but care can be taken that
they do not bite or inoculate their mad humours, or with their dogs’
teeth gnaw the bones and foundations of truth.
Detractors, mummers, and writers defiled with abuse, as I resolved with
myself never to read them, satisfied that nothing solid or excellent,
nothing but foul terms, was to be expected from them, so have I held
them still less worthy of an answer. Let them consume on their own ill
nature; they will scarcely find many well-disposed readers, I imagine,
nor does God give that which is most excellent and chiefly to be
desired--wisdom, to the wicked; let them go on railing, I say, until
they are weary, if not ashamed.
If for the sake of studying the meaner animals you should even enter the
bakehouse with Heraclitus, as related in Aristotle, I bid you approach;
for neither are the immortal Gods absent here, and the great and
almighty Father is sometimes most visible in His lesser, and to the eye
least considerable works.[112]
In my book on the Motion of the Heart and Blood in Animals, I have only
adduced those facts from among many other observations, by which either
errors were best refuted, or truth was most strongly supported; I have
left many proofs, won by dissection and appreciable to sense, as
redundant and unnecessary; some of these, however, I now supply in brief
terms, for the sake of the studious, and those who have expressed their
desire to have them.
The authority of Galen is of such weight with all, that I have seen
several hesitate greatly with that experiment before them, in which the
artery is tied upon a tube placed within its cavity; and by which it is
proposed to prove that the arterial pulse is produced by a power
communicated from the heart through the coats of the arteries, and not
from the shock of the blood contained within them; and thence, that the
arteries dilate as bellows, are not filled as sacs. This experiment is
spoken of by Vesalius, the celebrated anatomist; but neither Vesalius
nor Galen says that he had tried the experiment, which, however, I did.
Vesalius only prescribes, and Galen advises it, to those anxious to
discover the truth, and for their better assurance, not thinking of the
difficulties that attend its performance, nor of its futility when done;
for indeed, although executed with the greatest skill, it supplies
nothing in support of the opinion which maintains that the coats of the
vessel are the cause of the pulse; it much rather proclaims that this is
owing to the impulse of the blood. For the moment you have thrown your
ligature around the artery upon the reed or tube, immediately, by the
force of the blood thrown in from above, it is dilated beyond the circle
of the tube, by which the flow is impeded, and the shock is broken; so
that the artery which is tied only pulsates obscurely, being now cut off
from the full force of the blood that flows through it, the shock being
reverberated, as it were, from that part of the vessel which is above
the ligature; but if the artery below the ligature be now divided, the
contrary of what has been maintained will be apparent, from the spurting
of the blood impelled through the tube; just as happens in the cases of
aneurism, referred to in my book on the Motion of the Blood, which arise
from an erosion of the coats of the vessel, and when the blood is
contained in a membranous sac, formed not by the coats of the vessel
dilated, but preternaturally produced from the surrounding tissues and
flesh. The arteries beyond an aneurism of this kind will be felt beating
very feebly, whilst in those above it and in the swelling itself the
pulse will be perceived of great strength and fulness. And here we
cannot imagine that the pulsation and dilatation take place by the coats
of the arteries, or any power communicated to the walls of the sac; they
are plainly due to the shock of the blood.
But that the error of Vesalius, and the inexperience of those who assert
their belief that the part below the tube does not pulsate when the
ligature is tied, may be made the more apparent, I can state, after
having made the trial, that the inferior part will continue to pulsate
if the experiment be properly performed; and whilst they say that when
you have undone the ligature the inferior arteries begin again to
pulsate, I maintain that the part below beats less forcibly when the
ligature is untied than it did when the thread was still tight. But the
effusion of blood from the wound confuses everything, and renders the
whole experiment unsatisfactory and nugatory, so that nothing certain
can be shown, by reason, as I have said, of the hemorrhage. But if, as I
know by experience, you lay bare an artery, and control the divided
portion by the pressure of your fingers, you may try many things at
pleasure by which the truth will be made to appear. In the first place,
you will feel the blood coming down in the artery at each pulsation,
and visibly dilating the vessel. You may also at will suffer the blood
to escape, by relaxing the pressure, and leaving a small outlet; and you
will see that it jets out with each stroke, with each contraction of the
heart, and with each dilatation of the artery, as I have said in
speaking of arteriotomy, and the experiment of perforating the heart.
And if you suffer the efflux to go on uninterruptedly, either from the
simple divided artery or from a tube inserted into it, you will be able
to perceive by the sight, and if you apply your hand, by the touch
likewise, every character of the stroke of the heart in the jet; the
rhythm, order, intermission, force, &c., of its pulsations, all becoming
sensible there, no otherwise than would the jets from a syringe, pushed
in succession and with different degrees of force, received upon the
palm of the hand, be obvious to sight and touch. I have occasionally
observed the jet from a divided carotid artery to be so forcible, that,
when received on the hand, the blood rebounded to the distance of four
or five feet.
But that the question under discussion, viz.--that the pulsific power
does not proceed from the heart by the coats of the vessels, may be set
in yet a clearer light, I beg here to refer to a portion of the
descending aorta, about a span in length, with its division into the two
crural trunks, which I removed from the body of a nobleman, and which is
converted into a bony tube; by this hollow tube, nevertheless, did the
arterial blood reach the lower extremities of this nobleman during his
life, and cause the arteries in these to beat; and yet the main trunk
was precisely in the same condition as is the artery in the experiment
of Galen, when it is tied upon a hollow tube; where it was converted
into bone it could neither dilate nor contract like bellows, nor
transmit the pulsific power from the heart to the inferior vessels; it
could not convey a force which it was incapable of receiving through the
solid matter of the bone. In spite of all, however, I well remember to
have frequently noted the pulse in the legs and feet of this patient
whilst he lived, for I was myself his most attentive physician, and he
my very particular friend. The arteries in the inferior extremities of
this nobleman must therefore and of necessity have been dilated by the
impulse of the blood like flaccid sacs, and not have expanded in the
manner of bellows through the action of their tunics. It is obvious,
that whether an artery be tied over a hollow tube, or its tunics be
converted into a bony and unyielding canal, the interruption to the
pulsific power in the inferior part of the vessel must be the same.
I have known another instance in which a portion of the aorta near the
heart was found converted into bone, in the body of a nobleman, a man of
great muscular strength. The experiment of Galen, therefore, or, at all
events, a state analogous to it, not effected on purpose but encountered
by accident, makes it sufficiently to appear, that compression or
ligature of the coats of an artery does not interfere with the pulsative
properties of its derivative branches; and indeed, if the experiment
which Galen recommends were properly performed by any one, its results
would be found in opposition to the views which Vesalius believed they
would support.
But we do not therefore deny everything like motion to the tunics of the
arteries; on the contrary, we allow them the same motions which we
concede to the heart, viz., a diastole, and a systole or return from the
distended to the natural state; this much we believe to be effected by a
power inherent in the coats themselves. But it is to be observed, that
they are not both dilated and contracted by the same, but by different
causes and means; as may be observed of the motions of all parts, and of
the ventricle of the heart itself, which is distended by the auricle,
contracted by its own inherent power; so, the arteries are dilated by
the stroke of the heart, but they contract or collapse of
themselves.[113]
You may also perform another experiment at the same time: if you fill
one of two basins of the same size with blood issuing per saltum from an
artery, the other with venous blood from a vein of the same animal, you
will have an opportunity of perceiving by the eye, both immediately and
by and by, when the blood in either vessel has become cold, what
differences there are between them. You will find that it is not as they
believe who fancy that there is one kind of blood in the arteries and
another in the veins, that in the arteries being of a more florid
colour, more frothy, and imbued with an abundance of I know not what
spirits, effervescing and swelling, and occupying a greater space, like
milk or honey set upon the fire. For were the blood which is thrown from
the left ventricle of the heart into the arteries, fermented into any
such frothy and flatulent fluid, so that a drop or two distended the
whole cavity of the aorta; unquestionably, upon the subsidence of this
fermentation, the blood would return to its original quantity of a few
drops; (and this, indeed, is the reason that some assign for the usually
empty state of the arteries in the dead body;) and so should it be with
the arterial blood in the cup, for so it is with boiling milk and honey
when they come to cool. But if in either basin you find blood nearly of
the same colour, not of very different consistency in the coagulated
state, forcing out serum in the same manner, and filling the cups to the
same height when cold that it did when hot, this will be enough for any
one to rest his faith upon, and afford argument enough, I think, for
rejecting the dreams that have been promulgated on the subject. Sense
and reason alike assure us that the blood contained in the left
ventricle is not of a different nature from that in the right. And then,
when we see that the mouth of the pulmonary artery is of the same size
as the aorta, and in other respects equal to that vessel, it were
imperative on us to affirm that the pulmonary artery was distended by a
single drop of spumous blood, as well as the aorta, and so that the
right as well as the left side of the heart was filled with a brisk or
fermenting blood.
The particulars which especially dispose men’s minds to admit diversity
in the arterial and venous blood are three in number: one, because in
arteriotomy the blood that flows is of a more florid hue than that which
escapes from a vein; a second, because in the dissection of dead bodies
the left ventricle of the heart, and the arteries in general, are mostly
found empty; a third, because the arterial blood is believed to be more
spirituous, and being replete with spirit is made to occupy a much
larger space. The causes and reasons, however, wherefore all these
things are so, present themselves to us when we ask after them.
1st. With reference to the colour it is to be observed, that wherever
the blood issues by a very small orifice, it is in some measure
strained, and the thinner and lighter part, which usually swims on the
top and is the most penetrating, is emitted. Thus, in phlebotomy, when
the blood escapes forcibly and to a distance, in a full stream, and from
a large orifice, it is thicker, has more body, and a darker colour; but,
if it flows from a small orifice, and only drop by drop, as it usually
does when the bleeding fillet is untied, it is of a brighter hue; for
then it is strained as it were, and the thinner and more penetrating
portion only escapes; in the same way, in the bleeding from the nose, in
that which takes place from a leech-bite, or from scarifications, or in
any other way by diapedesis or transudation, the blood is always seen to
have a brighter cast, because the thickness and firmness of the coats of
the arteries render the outlet or outlets smaller, and less disposed to
yield a ready passage to the outpouring blood; it happens also that when
fat persons, are let blood, the orifice of the vein is apt to be
compressed by the subcutaneous fat, by which the blood is made to appear
thinner, more florid, and in some sort arterious. On the other hand, the
blood that flows into a basin from a large artery freely divided, will
look venous. The blood in the lungs is of a much more florid colour than
it is in the arteries, and we know how it is strained through the
pulmonary tissue.
2d. The emptiness of the arteries in the dead body, which probably
misled Erasistratus in supposing that they only contained aereal
spirits, is caused by this, that when respiration ceases the lungs
collapse, and then the passages through them are closed; the heart,
however, continues for a time to contract upon the blood, whence we find
the left auricle more contracted, and the corresponding ventricle, as
well as the arteries at large, appearing empty, simply because there is
no supply of blood flowing round to fill them. In cases, however, in
which the heart has ceased to pulsate and the lungs to afford a passage
to the blood simultaneously, as in those who have died from drowning or
syncope, or who die suddenly, you will find the arteries, as well as the
veins, full of blood.
3d. With reference to the third point, or that of the spirits, it may be
said that, as it is still a question what they are, how extant in the
body, of what consistency, whether separate and distinct from the blood
and solids, or mingled with these,--upon each and all of these points
there are so many and such conflicting opinions, that it is not
wonderful that the spirits, whose nature is thus left so wholly
ambiguous, should serve as the common subterfuge of ignorance. Persons
of limited information, when they are at a loss to assign a cause for
anything, very commonly reply that it is done by the spirits; and so
they bring the spirits into play upon all occasions; even as indifferent
poets are always thrusting the gods upon the stage as a means of
unravelling the plot, and bringing about the catastrophe.
Fernelius, and many others, suppose that there are aereal spirits and
invisible substances. Fernelius proves that there are animal spirits, by
saying that the cells in the brain are apparently unoccupied, and as
nature abhors a vacuum, he concludes that in the living body they are
filled with spirits, just as Erasistratus had held that, because the
arteries were empty of blood, therefore they must be filled with
spirits. But Medical Schools admit three kinds of spirits: the natural
spirits flowing through the veins, the vital spirits through the
arteries, and the animal spirits through the nerves; whence physicians
say, out of Galen, that sometimes the parts of the brain are oppressed
by sympathy, because the faculty with the essence, i. e., the spirit, is
overwhelmed; and sometimes this happens independently of the essence.
Farther, besides the three orders of influxive spirits adverted to, a
like number of implanted or stationary spirits seem to be acknowledged;
but we have found none of all these spirits by dissection, neither in
the veins, nerves, arteries, nor other parts of living animals. Some
speak of corporeal, others of incorporeal spirits; and they who advocate
the corporeal spirits will have the blood, or the thinner portion of the
blood, to be the bond of union with the soul, the spirit being contained
in the blood as the flame is in the smoke of a lamp or candle, and held
admixed by the incessant motion of the fluid; others, again, distinguish
between the spirits and the blood. They who advocate incorporeal spirits
have no ground of experience to stand upon; their spirits indeed are
synonymous with powers or faculties, such as a concoctive spirit, a
chylopoietic spirit, a procreative spirit, &c.--they admit as many
spirits, in short, as there are faculties or organs.
But then the schoolmen speak of a spirit of fortitude, prudence,
patience, and the other virtues, and also of a most holy spirit of
wisdom, and of every divine gift; and they besides suppose that there
are good and evil spirits that roam about or possess the body, that
assist or cast obstacles in the way. They hold some diseases to be owing
to a Cacodæmon or evil spirit, as there are others that are due to a
cacochemy or defective assimilation.
Although there is nothing more uncertain and questionable, then, than
the doctrine of spirits that is proposed to us, nevertheless physicians
seem for the major part to conclude, with Hippocrates, that our body is
composed or made up of three elements, viz., containing parts, contained
parts, and causes of action, spirits being understood by the latter
term. But if spirits are to be taken as synonymous with causes of
activity, whatever has power in the living body and a faculty of action
must be included under the denomination. It would appear, therefore,
that all spirits were neither aereal substances, nor powers, nor habits;
and that all were not incorporeal.
But keeping in view the points that especially interest us, others, as
leading to tediousness, being left unnoticed, it seems that the spirits
which flow by the veins or the arteries are not distinct from the blood,
any more than the flame of a lamp is distinct from the inflammable
vapour that is on fire; in short, that the blood and these spirits
signify one and the same thing, though different,--like generous wine
and its spirit; for as wine, when it has lost all its spirit, is no
longer wine, but a vapid liquor or vinegar; so blood without spirit is
not blood, but something else--clot or cruor; even as a hand of stone,
or of a dead body, is no hand in the most complete sense, neither is
blood void of the vital principle proper blood; it is immediately to be
held as corrupt when deprived of its spirit. The spirit therefore which
inheres in the arteries, and especially in the blood which fills them,
is to be regarded either as its act or agent, in the same way as the
spirit of wine in wine, and the spirit of aqua vitæ in brandy, or as a
flame kindled in alcohol, which lives and feeds on, or is nourished by
itself. The blood consequently, though richly imbued with spirits, does
not swell, nor ferment, nor rise to a head through them, so as to
require and occupy a larger space,--a fact that may be ascertained
beyond the possibility of question by the two cups of equal size; it is
to be regarded as wine, possessed of a large amount of spirits, or, in
the Hippocratic sense, of signal powers of acting and effecting.
It is therefore the same blood in the arteries that is found in the
veins, although it may be admitted to be more spirituous, possessed of
higher vital force in the former than in the latter; but it is not
changed into anything more vaporous, or more aereal, as if there were no
spirits but such as are aereal, and no cause of action or activity that
is not of the nature of flatus or wind. But neither the animal, natural,
nor vital spirits which inhere in the solids, such as the ligaments and
nerves (especially if they be of so many different species), and are
contained within the viewless interstices of the tissues, are to be
regarded as so many different aereal forms, or kinds of vapour.
And here I would gladly be informed by those who admit corporeal
spirits, but of a gaseous or vaporous consistency, in the bodies of
animals, whether or not they have the power of passing hither and
thither, like distinct bodies independently of the blood? Or whether the
spirits follow the blood in its motions, either as integral parts of the
fluid or as indissolubly connected with it, so that they can neither
quit the tissues nor pass hither nor thither without the influx and
reflux, and motion of the blood? For if the spirits exhaling from the
blood, like the vapour of water attenuated by heat, exist in a state of
constant flow and succession as the pabulum of the tissues, it
necessarily follows that they are not distinct from this pabulum, but
are incessantly disappearing; whereby it seems that they can neither
have influx nor reflux, nor passage, nor yet remain at rest without the
influx, the reflux, the passage [or stasis] of the blood, which is the
fluid that serves as their vehicle or pabulum.
And next I desire to know of those who tell us that the spirits are
formed in the heart, being compounded of the vapours or exhalations of
the blood (excited either by the heat of the heart or the concussion)
and the inspired air, whether such spirits are not to be accounted much
colder than the blood, seeing that both the elements of their
composition, namely, air and vapour, are much colder? For the vapour of
boiling water is much more bearable than the water itself; the flame of
a candle is less burning than the red-hot snuff, and burning charcoal
than incandescent iron or brass. Whence it would appear that spirits of
this nature rather receive their heat from the blood, than that the
blood is warmed by these spirits; such spirits are rather to be regarded
as fumes and excrementitious effluvia proceeding from the body in the
manner of odours, than in any way as natural artificers of the tissues;
a conclusion which we are the more disposed to admit, when we see that
they so speedily lose any virtue they may possess, and which they had
derived from the blood as their source,--they are at best of a very
frail and evanescent nature. Whence also it becomes probable that the
expiration of the lungs is a means by which these vapours being cast
off, the blood is fanned and purified; whilst inspiration is a means by
which the blood in its passage between the two ventricles of the heart
is tempered by the cold of the ambient atmosphere, lest, getting heated,
and blown up with a kind of fermentation, like milk or honey set over
the fire, it should so distend the lungs that the animal got suffocated;
somewhat in the same way, perchance, as one labouring under a severe
asthma, which Galen himself seems to refer to its proper cause when he
says it is owing to an obstruction of the smaller arteries, viz., the
vasa venosa et arteriosa. And I have found by experience that patients
affected with asthma might be brought out of states of very imminent
danger by having cupping-glasses applied, and a plentiful and sudden
affusion of cold water [upon the chest]. Thus much--and perhaps it is
more than was necessary--have I said on the subject of spirits in this
place, for I felt it proper to define them, and to say something of
their nature in a physiological disquisition.
I shall only further add, that they who descant on the calidum innatum
or innate heat, as an instrument of nature available for every purpose,
and who speak of the necessity of heat as the cherisher and retainer in
life of the several parts of the body, who at the same time admit that
this heat cannot exist unless connected with something, and because they
find no substance of anything like commensurate mobility, or which might
keep pace with the rapid influx and reflux of this heat (in affections
of the mind especially), take refuge in spirits as most subtile
substances, possessed of the most penetrating qualities, and highest
mobility--these persons see nothing less than the wonderful and almost
divine character of the natural operations as proceeding from the
instrumentality of this common agent, viz., the calidum innatum; they
farther regard these spirits as of a sublime, lucid, ethereal,
celestial, or divine nature, and the bond of the soul; even as the
vulgar and unlettered, when they do not comprehend the causes of various
effects, refer them to the immediate interposition of the Deity. Whence
they declare that the heat perpetually flowing into the several parts is
in virtue of the influx of spirits through the channels of the arteries;
as if the blood could neither move so swiftly, nor penetrate so
intimately, nor cherish so effectually. And such faith do they put in
this opinion, such lengths are they carried by their belief, that they
deny the contents of the arteries to be blood! And then they proceed
with trivial reasonings to maintain that the arterial blood is of a
peculiar kind, or that the arteries are filled with such aereal spirits,
and not with blood; all the while, in opposition to everything which
Galen has advanced against Erasistratus, both on grounds of experiment
and of reason. But that arterial blood differs in nothing essential from
venous blood has been already sufficiently demonstrated; and our senses
likewise assure us that the blood and spirits do not flow in the
arteries separately and disjoined, but as one body.
We have occasion to observe so often as our hands, feet, or ears have
become stiff and cold, that as they recover again by the warmth that
flows into them, they acquire their natural colour and heat
simultaneously; that the veins which had become small and shrunk, swell
visibly and enlarge, so that when they regain their heat suddenly they
become painful; from which it appears, that that which by its influx
brings heat is the same which causes repletion and colour; now this can
be and is nothing but blood.
When an artery and a vein are divided, any one may clearly see that the
part of the vein towards the heart pours out no blood, whilst that
beyond the wound gives a torrent; the divided artery, on the contrary,
(as in my experiment on the carotids,) pours out a flood of pure blood
from the orifice next the heart, and in jets as if it were forced from a
syringe, whilst from the further orifice of the divided artery little or
no blood escapes. This experiment therefore plainly proves in what
direction the current sets in either order of vessels--towards the heart
in the veins, from the heart in the arteries; it also shows with what
velocity the current moves, not gradually and by drops, but even with
violence. And lest any one, by way of subterfuge, should take shelter in
the notion of invisible spirits, let the orifice of the divided vessel
be plunged under water or oil, when, if there be any air contained in
it, the fact will be proclaimed by a succession of visible bubbles.
Hornets, wasps, and other insects of the same description plunged in
oil, and so suffocated, emit bubbles of air from their tail whilst they
are dying; whence it is not improbable that they thus respire when
alive; for all animals submerged and drowned, when they finally sink to
the bottom and die, emit bubbles of air from the mouth and lungs. It is
also demonstrated by the same experiment, that the valves of the veins
act with such accuracy, that air blown into them does not penetrate;
much less then can blood make its way through them:--it is certain, I
say, that neither sensibly nor insensibly, nor gradually and drop by
drop, can any blood pass from the heart by the veins.
And that no one may seek shelter in asserting that these things are so
when nature is disturbed and opposed, but not when she is left to
herself and at liberty to act; that the same things do not come to pass
in morbid and unusual states as in the healthy and natural condition;
they are to be met by saying, that if it were so, if it happened that so
much blood was lost from the farther orifice of a divided vein because
nature was disturbed, still that the incision does not close the nearer
orifice, from which nothing either escapes or can be expressed, whether
nature be disturbed or not. Others argue in the same way, maintaining
that, although the blood immediately spurts out in such profusion with
every beat, when an artery is divided near the heart, it does not
therefore follow that the blood is propelled by the pulse when the heart
and artery are entire. It is most probable, however, that every stroke
impels something; and that there would be no pulse of the container,
without an impulse being communicated to the thing contained, seems
certain. Yet some, that they may seize upon a farther means of defence,
and escape the necessity of admitting the circulation, do not fear to
affirm that the arteries in the living body and in the natural state are
already so full of blood, that they are incapable of receiving another
drop; and so also of the ventricles of the heart. But it is indubitable
that, whatever the degree of distension and the extent of contraction
of the heart and arteries, they are still in a condition to receive an
additional quantity of blood forced into them, and that this is far more
than is usually reckoned in grains or drops, seems also certain. For if
the ventricles become so excessively distended that they will admit no
more blood, the heart ceases to beat, (and we have occasional
opportunities of observing the fact in our vivisections,) and,
continuing tense and resisting, death by asphyxia ensues.
In the work on the Motion of the Heart and Blood, I have already
sufficiently discussed the question as to whether the blood in its
motion was attracted, or impelled, or moved by its own inherent nature.
I have there also spoken at length of the action and office, of the
dilatation and contraction of the heart, and have shown what these truly
are, and how the heart contracts during the diastole of the arteries; so
that I must hold those who take points for dispute from among them as
either not understanding the subject, or as unwilling to look at things
for themselves, and to investigate them with their own senses.[114]
For my part, I believe that no other kind of attraction can be
demonstrated in the living body save that of the nutriment, which
gradually and incessantly passes on to supply the waste that takes place
in the tissues; in the same way as the oil rises in the wick of a lamp
to be consumed by the flame. Whence I conclude that the primary and
common organ of all sensible attraction and impulsion is of the nature
of sinew (nervus), or fibre, or muscle, and this to the end that it may
be contractile, that contracting it may be shortened, and so either
stretch out, draw towards, or propel. But these topics will be better
discussed elsewhere, when we speak of the organs of motion in the animal
body.
To those who repudiate the circulation because they neither see the
efficient nor final cause of it, and who exclaim, cui bono? I have yet
to reply, having hitherto taken no note of the ground of objection which
they take up. And first I own I am of opinion that our first duty is to
inquire whether the thing be or not, before asking wherefore it is? for
from the facts and circumstances which meet us in the circulation
admitted, established, the ends and objects of its institution are
especially to be sought. Meantime I would only ask, how many things we
admit in physiology, pathology, and therapeutics, the causes of which
are unknown to us? That there are many, no one doubts--the causes of
putrid fevers, of revulsions, of the purgation of excrementitious
matters, among the number.
Whoever, therefore, sets himself in opposition to the circulation,
because, if it be acknowledged, he cannot account for a variety of
medical problems, nor in the treatment of diseases and the
administration of medicines, give satisfactory reasons for the phenomena
that appear; or who will not see that the precepts he has received from
his teachers are false; or who thinks it unseemly to give up accredited
opinions; or who regards it as in some sort criminal to call in question
doctrines that have descended through a long succession of ages, and
carry the authority of the ancients;--to all of these I reply: that the
facts cognizable by the senses wait upon no opinions, and that the works
of nature bow to no antiquity; for indeed there is nothing either more
ancient or of higher authority than nature.
To those who object to the circulation as throwing obstacles in the way
of their explanations of the phenomena that occur in medical cases (and
there are persons who will not be content to take up with a new system,
unless it explains everything, as in astronomy), and who oppose it with
their own erroneous assumptions, such as that, if it be true, phlebotomy
cannot cause revulsion, seeing that the blood will still continue to be
forced into the affected part; that the passage of excrementitious
matters and foul humours through the heart, that most noble and
principal viscus, is to be apprehended; that an efflux and excretion,
occasionally of foul and corrupt blood, takes place from the same body,
from different parts, even from the same part and at the same time,
which, were the blood agitated by a continuous current, would be shaken
and effectually mixed in passing through the heart, and many points of
the like kind admitted in our medical schools, which are seen to be
repugnant to the doctrine of the circulation,--to them I shall not
answer farther here, than that the circulation is not always the same in
every place, and at every time, but is contingent upon many
circumstances: the more rapid or slower motion of the blood, the
strength or weakness of the heart as the propelling organ, the quantity
and quality or constitution of the blood, the rigidity or laxity of the
tissues, and the like. A thicker blood, of course, moves more slowly
through narrower channels; it is more effectually strained in its
passage through the substance of the liver than through that of the
lungs. It has not the same velocity through flesh and the softer
parenchymatous structures and through sinewy parts of greater
compactness and consistency: for the thinner and purer and more
spirituous part permeates more quickly, the thicker more earthy and
indifferently concocted portion moves more slowly, or is refused
admission. The nutritive portion, or ultimate aliment of the tissues,
the dew or cambium, is of a more penetrating nature, inasmuch as it has
to be added everywhere, and to everything that grows and is nourished in
its length and thickness, even to the horns, nails, hair and feathers;
and then the excrementitious matters have to be secreted in some places,
where they accumulate, and either prove a burthen or are concocted. But
I do not imagine that the excrementitious fluids or bad humours when
once separated, nor the milk, the phlegm, and the spermatic fluid, nor
the ultimate nutritive part, the dew or cambium, necessarily circulate
with the blood: that which nourishes every part adheres and becomes
agglutinated to it. Upon each of these topics and various others
besides, to be discussed and demonstrated in their several places, viz.,
in the physiology and other parts of the art of medicine, as well as of
the consequences, advantages or disadvantages of the circulation of the
blood, I do not mean to touch here; it were fruitless indeed to do so
until the circulation has been established and conceded as a fact. And
here the example of astronomy is by no means to be followed, in which
from mere appearances or phenomena that which is in fact, and the reason
wherefore it is so, are investigated. But as he who inquires into the
cause of an eclipse must be placed beyond the moon if he would ascertain
it by sense, and not by reason, still, in reference to things sensible,
things that come under the cognizance of the senses, no more certain
demonstration or means of gaining faith can be adduced than examination
by the senses, than ocular inspection.
There is one remarkable experiment which I would have every one try who
is anxious for truth, and by which it is clearly shown that the arterial
pulse is owing to the impulse of the blood. Let a portion of the dried
intestine of a dog or wolf, or any other animal, such as we see hung up
in the druggists’ shops, be taken and filled with water, and then
secured at both ends like a sausage: by tapping with the finger at one
extremity, you will immediately feel a pulse and vibration in any other
part to which you apply the fingers, as you do when you feel the pulse
at the wrist. In this way, indeed, and also by means of a distended
vein, you may accurately either in the dead or living body, imitate and
show every variety of the pulse, whether as to force, frequency, volume,
rhythm, &c. Just as in a long bladder full of fluid, or in an oblong
drum, every stroke upon one end is immediately felt at the other; so
also in a dropsy of the belly and in abscesses under the skin, we are
accustomed to distinguish between collections of fluid and of air,
between anasarca and tympanites in particular. If a slap or push given
on one side is clearly felt by a hand placed on the other side, we judge
the case to be tympanites[?]; not, as falsely asserted, because we hear
a sound like that of a drum, and this produced by flatus, which never
happens[?]; but because, as in a drum, every the slightest tap passes
through and produces a certain vibration on the opposite side; for it
indicates that there is a serous and ichorous substance present, of such
a consistency as urine, and not any sluggish or viscid matter as in
anasarca, which when struck retains the impress of the blow or pressure,
and does not transmit the impulse.
Having brought forward this experiment I may observe, that a most
formidable objection to the circulation of the blood rises out of it,
which, however, has neither been observed nor adduced by any one who has
written against me. When we see by the experiment just described, that
the systole and diastole of the pulse can be accurately imitated without
any escape of fluid, it is obvious that the same thing may take place in
the arteries from the stroke of the heart, without the necessity for a
circulation, but like Euripus, with a mere motion of the blood
alternately backwards and forwards. But we have already satisfactorily
replied to this difficulty; and now we venture to say that the thing
could not be so in the arteries of a living animal; to be assured of
this it is enough to see that the right auricle is incessantly injecting
the right ventricle of the heart with blood, the return of which is
effectually prevented by the tricuspid valves; the left auricle in like
manner filling the left ventricle, the return of the blood there being
opposed by the mitral valves; and then the ventricles in their turn are
propelling the blood into either great artery, the reflux in each being
prevented by the sigmoid valves in its orifice. Either, consequently,
the blood must move on incessantly through the lungs, and in like manner
within the arteries of the body, or stagnating and pent up, it must
rupture the containing vessels, or choke the heart by over distension,
as I have shown it to do in the vivisection of a snake, described in my
book on the Motion of the Blood. To resolve this doubt I shall relate
two experiments among many others, the first of which, indeed, I have
already adduced, and which show with singular clearness that the blood
flows incessantly and with great force and in ample abundance in the
veins towards the heart. The internal jugular vein of a live fallow deer
having been exposed, (many of the nobility and his most serene majesty
the king, my master, being present,) was divided; but a few drops of
blood were observed to escape from the lower orifice rising up from
under the clavicle; whilst from the superior orifice of the vein and
coming down from the head, a round torrent of blood gushed forth. You
may observe the same fact any day in practising phlebotomy: if with a
finger you compress the vein a little below the orifice, the flow of
blood is immediately arrested; but the pressure being removed, forthwith
the flow returns as before.
From any long vein of the forearm get rid of the blood as much as
possible by holding the hand aloft and pressing the blood towards the
trunk, you will perceive the vein collapsed and leaving, as it were, in
a furrow of the skin; but now compress the vein with the point of a
finger, and you will immediately perceive all that part of it which is
towards the hand, to enlarge and to become distended with the blood that
is coming from the hand. How comes it when the breath is held and the
lungs thereby compressed, a large quantity of air having been taken in,
that the vessels of the chest are at the same time obstructed, the blood
driven into the face, and the eyes rendered red and suffused? Why is it,
as Aristotle asks in his problems, that all the actions are more
energetically performed when the breath is held than when it is given?
In like manner, when the frontal and lingual veins are incised, the
blood is made to flow more freely by compressing the neck and holding
the breath. I have several times opened the breast and pericardium of a
man within two hours after his execution by hanging, and before the
colour had totally left the face, and in presence of many witnesses,
have demonstrated the right auricle of the heart and the lungs distended
with blood; the auricle in particular of the size of a large man’s fist,
and so full of blood that it looked as if it would burst. This great
distension, however, had disappeared next day, the body having stiffened
and become cold, and the blood having made its escape through various
channels. These and other similar facts, therefore, make it sufficiently
certain that the blood flows through the whole of the veins of the body
towards the base of the heart, and that unless there was a further
passage afforded it, it would be pent up in these channels, or would
oppress and overwhelm the heart; as on the other hand, did it not flow
outwards by the arteries, but was found regurgitating, it would soon be
seen how much it would oppress.
I add another observation. A noble knight, Sir Robert Darcy, an ancestor
of that celebrated physician and most learned man, my very dear friend
Dr. Argent, when he had reached to about the middle period of life, made
frequent complaint of a certain distressing pain in the chest,
especially in the night season; so that dreading at one time syncope, at
another suffocation in his attacks he led an unquiet and anxious life.
He tried many remedies in vain, having had the advice of almost every
medical man. The disease going on from bad to worse, he by and by became
cachectic and dropsical, and finally, grievously distressed, he died in
one of his paroxysms. In the body of this gentleman, at the inspection
of which there were present Dr. Argent, then president of the College of
Physicians, and Dr. Gorge, a distinguished theologian and preacher, who
was pastor of the parish, we found the wall of the left ventricle of the
heart ruptured, having a rent in it of size sufficient to admit any of
my fingers, although the wall itself appeared sufficiently thick and
strong; this laceration had apparently been caused by an impediment to
the passage of the blood from the left ventricle into the arteries.
I was acquainted with another strong man, who having received an injury
and affront from one more powerful than himself, and upon whom he could
not have his revenge, was so overcome with hatred and spite and passion,
which he yet communicated to no one, that at last he fell into a strange
distemper, suffering from extreme oppression and pain of the heart and
breast, and the prescriptions of none of the very best physicians
proving of any avail, he fell in the course of a few years into a
scorbutic and cachectic state, became tabid and died. This patient only
received some little relief when the whole of his chest was pummelled or
kneaded by a strong man, as a baker kneads dough. His friends thought
him poisoned by some maleficent influence, or possessed with an evil
spirit. His jugular arteries, enlarged to the size of the thumb, looked
like the aorta itself, or they were as large as the descending aorta;
they had pulsated violently, and appeared like two long aneurisms. These
symptoms had led to trying the effects of arteriotomy in the temples,
but with no relief. In the dead body I found the heart and aorta so much
gorged and distended with blood, that the cavities of the ventricles
equalled those of a bullock’s heart in size. Such is the force of the
blood pent up, and such are the effects of its impulse.
We may therefore conclude, that although there may be impulse without
any exit, as illustrated in the experiment lately spoken of, still that
this could not take place in the vessels of living creatures without
most serious dangers and impediments. From this, however, it is manifest
that the blood in its course does not everywhere pass with the same
celerity, neither with the same force in all places and at all times,
but that it varies greatly according to age, sex, temperament, habit of
body, and other contingent circumstances, external as well as internal,
natural or non-natural. For it does not course through intricate and
obstructed passages with the same readiness that it does through
straight, unimpeded, and pervious channels. Neither does it run through
close, hard, and crowded parts, with the same velocity as through
spongy, soft, and permeable tissues. Neither does it flow and penetrate
with such swiftness when the impulse [of the heart] is slow and weak, as
when this is forcible and frequent, in which case the blood is driven
onwards with vigour and in large quantity. Nor is the same blood, when
it has become more consistent or earthy, so penetrative as when it is
more serous and attenuated or liquid. And then it seems only reasonable
to think that the blood in its circuit passes more slowly through the
kidneys than through the substance of the heart; more swiftly through
the liver than through the kidneys; through the spleen more quickly than
through the lungs, and through the lungs more speedily than through any
of the other viscera or the muscles, in proportion always to the
denseness or sponginess of the tissue of each.
We may be permitted to take the same view of the influence of age, sex,
temperament, and habit of body, whether this be hard or soft; of that of
the ambient cold which condenses bodies, and makes the veins in the
extremities to shrink and almost to disappear, and deprives the surface
both of colour and heat; and also of that of meat and drink which render
the blood more watery, by supplying fresh nutritive matter. From the
veins, therefore, the blood flows more freely in phlebotomy when the
body is warm than when it is cold. We also observe the signal influence
of the affections of the mind when a timid person is bled and happens to
faint: immediately the flow of blood is arrested, a deadly pallor
overspreads the surface, the limbs stiffen, the ears sing, the eyes are
dazzled or blinded, and, as it were, convulsed. But here I come upon a
field where I might roam freely and give myself up to speculation. And,
indeed, such a flood of light and truth breaks in upon me here; occasion
offers of explaining so many problems, of resolving so many doubts, of
discovering the causes of so many slighter and more serious diseases,
and of suggesting remedies for their cure, that the subject seems almost
to demand a separate treatise. And it will be my business in my ‘Medical
Observations,’ to lay before my reader matter upon all these topics
which shall be worthy of the gravest consideration.
And what indeed is more deserving of attention than the fact that in
almost every affection, appetite, hope, or fear, our body suffers, the
countenance changes, and the blood appears to course hither and thither.
In anger the eyes are fiery and the pupils contracted; in modesty the
cheeks are suffused with blushes; in fear, and under a sense of infamy
and of shame, the face is pale, but the ears burn as if for the evil
they heard or were to hear; in lust how quickly is the member distended
with blood and erected! But, above all, and this is of the highest
interest to the medical practitioner,--how speedily is pain relieved or
removed by the detraction of blood, the application of cupping-glasses,
or the compression of the artery which leads to a part? It sometimes
vanishes as if by magic. But these are topics that I must refer to my
‘Medical Observations,’ where they will be found exposed at length and
explained.
Some weak and inexperienced persons vainly seek by dialectics and
far-fetched arguments, either to upset or establish things that are only
to be founded on anatomical demonstration, and believed on the evidence
of the senses. He who truly desires to be informed of the question in
hand, and whether the facts alleged be sensible, visible, or not, must
be held bound either to look for himself, or to take on trust the
conclusions to which they have come who have looked; and indeed there is
no higher method of attaining to assurance and certainty. Who would
pretend to persuade those who had never tasted wine that it was a drink
much pleasanter to the palate than water? By what reasoning should we
give the blind from birth to know that the sun was luminous, and far
surpassed the stars in brightness? And so it is with the circulation of
the blood, which the world has now had before it for so many years,
illustrated by proofs cognizable by the senses, and confirmed by various
experiments. No one has yet been found to dispute the sensible facts,
the motion, efflux and afflux of the blood, by like observations based
on the evidence of sense, or to oppose the experiments adduced, by other
experiments of the same character; nay, no one has yet attempted an
opposition on the ground of ocular testimony.
There have not been wanting many who, inexperienced and ignorant of
anatomy, and making no appeal to the senses in their opposition, have,
on the contrary, met it with empty assertions, and mere suppositions,
with assertions derived from the lessons of teachers and captious
cavillings; many, too, have vainly sought refuge in words, and these not
always very nicely chosen, but reproachful and contumelious; which,
however, have no farther effect than to expose their utterer’s vanity
and weakness, and ill breeding and lack of the arguments that are to be
sought in the conclusions of the senses, and false sophistical
reasonings that seem utterly opposed to sense. Even as the waves of the
Sicilian sea, excited by the blast, dash against the rocks around
Charybdis, and then hiss and foam, and are tossed hither and thither; so
do they who reason against the evidence of their senses.
Were nothing to be acknowledged by the senses without evidence derived
from reason, or occasionally even contrary to the previously received
conclusions of reason, there would now be no problem left for
discussion. Had we not our most perfect assurances by the senses, and
were not their perceptions confirmed by reasoning, in the same way as
geometricians proceed with their figures, we should admit no science of
any kind; for it is the business of geometry, from things sensible, to
make rational demonstration of things that are not sensible; to render
credible or certain things abstruse and beyond sense from things more
manifest and better known. Aristotle counsels us better when, in
treating of the generation of bees, he says:[115] “Faith is to be given
to reason, if the matters demonstrated agree with those that are
perceived by the senses; when the things have been thoroughly
scrutinized, then are the senses to be trusted rather than the reason.”
Whence it is our duty to approve or disapprove, to receive or reject
everything only after the most careful examination; but to examine, to
test whether anything have been well or ill advanced, to ascertain
whether some falsehood does not lurk under a proposition, it is
imperative on us to bring it to the proof of sense, and to admit or
reject it on the decision of sense. Whence Plato in his Critias, says,
that the explanation of those things is not difficult of which we can
have experience; whilst they are not of apt scientific apprehension who
have no experience.