|
With the calm quantitative account which a reader of
Hales'
"Statical Essays" will find given by that clergyman of
his
epoch-making physical experiments upon the blood-pressure, it
is
interesting to compare the following vivid qualitative recital
of
inferences made from surgical observations by his great
predecessor.
Harvey says:--
"Moreover, whoever shall have seen
and thought upon the amount
of difficulty and exertion with which the
blood is stanched by
compression, ligatures, or various appliances, when
it leaps
impetuously out of a petty artery, even the smallest,
which
has been cut or torn in two; and shall have seen or
thought
upon the amount of force with which the blood, as though
thrown
out from a syringe, flings off and drives before it the
whole
of the appliances, or traverses them--that man will hardly
believe it probable, I think, that any of the blood can pass
backward
against so great an impulse and influx of the entering
blood, unless
from a point whence it is driven back with equal
force."[254]
Harvey rightly discountenanced the ancient idea of
direct
anastomoses between the mouths of veins and the mouths of
arteries,
as opposed to fine and multiplied communications. In
some situations,
however, he admitted that ampler communications
exist comparable to such
anastomoses; and it throws light upon
his state of mind as to the movement of
the blood that, despite
his recognition of the very forcible exit of the
blood from the
arteries, he suggested in his old age that in the cases
aforesaid
regurgitation from vein to artery is guarded against by a
valvular
arrangement, the terminal part of the artery traversing the wall
of
the vein obliquely, as the ureter traverses the wall of the bladder
and
as the biliary duct traverses the wall of the duodenum.[255]
We should not
forget that in his day the capillary vessels, the
existence of the
corpuscles, and the chemistry of the blood were
still unknown; so that the
passage into the veins of the mysterious
hot vital liquid through the
"porosities" of the parts might
naturally present itself to his mind in a way
very strange to us. He
tells us this:--
"The blood does not take
its course through the looser texture
of flesh and parenchyma in the
same way as through the more
compact consistency of tendinous parts.
Indeed, the thinner and
purer and more spirituous part passes through
more quickly; the
thicker, more earthy, ill-composed[256] part tarries
longer and
is rejected."[257]
After more than twenty years of the
comment and criticism, called
forth by his treatise of 1628, he said to
Riolanus:--
"As to whether the moving blood be attracted, or
impelled, or
move itself by virtue of its own intrinsic nature, enough
has
been said in my little book on the motion of the heart and
blood."[258]
Yet about two years after the Exercises to Riolanus, Harvey,
in
writing a private letter, judged it necessary to accentuate,
as
follows, his denial that forces of attraction really play the part
in
physiology which the ancients had conceded to them. Speaking of
the impulsion
of the blood through the arteries, he says:--
"Indeed, the passage
of the blood into the veins is brought
about by that impulsion and not
by any dilatation of the veins
whereby, like bellows, they draw in the
blood."[259]
But, despite the foregoing utterances and other such, his
statements
are sometimes vague and sometimes quite unexpected, regarding
the
nature of the movement of the blood in the veins. Indeed, in 1628
he
speaks quite as a disciple of Aristotle. He says regarding the flow
in
the arteries:--
"For this distribution and movement of the blood
there is need
of impetus and violence and of an impeller such as the
heart.
Partly because the blood readily concentrates and gathers
together of itself--toward its seat of origin, as it were,[260]
or as a
part to the whole, or as a drop of the water sprinkled
upon a table to
the mass thereof--as the blood habitually
and very speedily does from
slight causes, from cold, fear,
horror, and other causes of this sort;
partly, also, because
the blood is pressed out of the capillary veins
into the small
branches and thence into the greater by the movements of
the
limbs and the compression of the muscles; the blood is more
disposed and prone to move from the circumference on the center
than the
other way, even supposing no valves to be present as
a hindrance. In
order, therefore, to relinquish its seat of
origin, and enter
constricted and colder places, and move in
opposition to its bent,[261]
the blood has need not only of
violence but of an impeller, such as is
the heart alone, and
after the fashion described
already."[262]
This picture of the blood hesitating to leave its warm
cardiac
birthplace for the chill regions of the periphery, but very ready
to
return, has a tone far from hydraulic, but may so much the
better
prepare us for the view, made public by Harvey in his old age,
that
the blood is the primal seat of the soul itself. Except in the
light
of the foregoing passage the following words would be quite
obscure.
He says that the auricles
"are filled as being the
storehouse and reservoir[263] of the
blood, the blood turning of itself
and compressed toward the
center by the movement of the
veins."[264]
With due allowance for the use of modes of expression no
longer
familiar we find Harvey in 1649 handling the venous flow with
no
very modern touch, in the following passage--a passage which
also reminds us
that not till twelve years later, four years
after Harvey's death, did
Malpighi announce his discovery of the
capillary blood-vessels in the lung of
the frog.[265] Harvey says to
Riolanus:--
"The arteries are never
depleted except into the veins or the
porosities of the parts, but are
continually stuffed full by the
pulse of the heart; but in the vena cava
and the circulatory
vessels, into which the blood glides at a quick pace
and hastens
toward the heart, there would be the greatest scarcity of
blood,
did not all the parts incessantly pour out again the
blood
poured into them. Add, also, that the impetus of the blood
which
is urged and driven at every pulsation into all parts of
the
second and third regions, forces the blood contained therein
from the porosities into the little veins and from the branches
into the
larger vessels; this being effected also by the motion
and compression
of the surrounding parts; for contents are
squeezed out of whatever
contains them, when it is compressed
and narrowed. So by the movements
of the muscles and limbs the
venous branches which creep on between are
pressed upon and
narrowed, and push on the blood from the lesser toward
the
greater."[266]
A similar touch of vagueness is perceptible
when the venous flow is
dealt with by Harvey in that very same resume of the
circulation
which seats the underlying cause of the pulse in the hot
blood
of the vena cava close to the auricle. In that resume he says
to
Riolanus:--
"I assert, further, that the blood in the veins
courses always
and everywhere from the lesser into the greater and
hastens from
all parts toward the heart; whence I gather that the
amount,
continuously sent into the arteries, which the arteries
have
received is transferred through the veins, and at length
returns
and flows back whence it first was impelled; and that in
this
wise the blood is moved in a circle in flux and reflux by
the
heart, by an impulsion the impetus of which forces the blood
through all the arterial filaments; and that afterward in a
continuous
flow from all parts it goes back through the veins,
one after another,
by which it is absorbed, drained away, and
transported."[267]
As
to the flow in the lungs Harvey says in the treatise of 1628:--
"It
being the will of nature that the blood itself be strained
through the
lungs, she was obliged to superadd the right
ventricle, in order that by
the beat thereof the blood might be
driven through the lungs themselves,
out of the vena cava into
the cavity of the left
ventricle."[268]
We have already found Harvey saying to Riolanus, in
regard to
the pulmonary transit, that the blood within the branches of
the
arterial vein
"cannot now go back in opposition to the
sigmoid valve, while
at the same time the lungs are widened and enlarged
and then
narrowed, by inspiration and expiration, and with the
lungs
their vessels also, and offer to the blood aforesaid a path
and
transit into the venous artery."[269]
More than thirty-two
years earlier Harvey had written in his
note-book the following
words:--
"N.B. The lungs by their movement in subsiding propel blood
from
the arterial vein into the venous artery and thence into
the
left auricle."[270]
When we review and ponder the foregoing
delineations of the
character of the movement of the blood, we may cease to
wonder
that Harvey did not recognize the simple hydraulic cause of
the
distention of the right auricle and felt obliged to seek a
more
recondite explanation thereof, finding this in an
Aristotelian
expansion of the hot blood.
CHAPTER
IX
THE BLOOD THE SEAT OF THE SOUL
No doctrine of Harvey sounds
stranger to a biologist of to-day than
his doctrine that the blood is the
seat of the soul; nor does any
other belief of the great discoverer reveal
him more clearly to be a
link between the old and the new; not simply an
innovator who fixed
a gulf between them. We have heard him explicitly deny in
his old
age the Aristotelian doctrine that the heart "is endowed with
soul."
We have seen that thirty-five years earlier he had jotted down
in
his note-book these words: "The soul is in the blood."[271] Let
us
study him now as he lays stress, not merely on the primacy of
the
blood, but on its psychological endowments.
Thirteen years before
the date of Harvey's note-book Shakspere's
play of "Hamlet" had appeared in
print; in which the prince speaks
thus of following his father's
ghost:--
"Why, what should be the fear?
I do not set my
life at a pin's fee;
And, for my soul, what can it do to
that,
Being a thing immortal as itself?"[272]
It has been
foreshadowed that for Harvey, the graduate of
Cambridge and of Padua, the
physician of the Renaissance, the word
"_anima_"--"soul"--did not simply mean
the immortal part of man,
as for Hamlet, but was equivalent to the "_psyche_"
of ancient
philosophy. In order, therefore, readily to follow Harvey's
thought
at this juncture, we must first, like him, go to the fountain
head;
for only sayings of Aristotle can give us a sufficient clue to
what
he, and after him Harvey, meant by "soul."
Aristotle says in his
treatise On Soul:--
"Some natural bodies have life and some have
not. By life we
mean the being nourished, and growing, and decaying, of
oneself."
In the same treatise he says further:--
"The soul
is that by which primarily we are alive, and
display sensation and
intellect; ... but it is not matter and
substratum."
Again he
says:--
"Were the eye an animal, vision would be the soul thereof;
for
reason indicates that vision is the essence of the eye.[273]
The
eye in its turn is the material [basis] of vision; which
latter
failing, the eye is not an eye except in name, like an eye
of
stone or in a drawing."
The doctrines of the foregoing three
passages are developed and made
more explicit in the following, still from
the treatise On Soul:--
"It is the presence of life, we say, which
makes the difference
between that which has soul and that which has not.
To amplify
regarding life: we call anything alive which possesses even
a
single one of the following: intellect, sensation, motion and
rest in space, and also the motion[274] involved in nutrition,
and both
decay and growth. Therefore, even all the plants are
held to be
alive."
A few lines further on Aristotle says, speaking of the power
or
faculty[275] of taking nourishment:--
"This can exist without
the others, but not the other faculties
without this, in mortal beings.
The aforesaid is clear in the
case of plants; for they possess no other
faculty of the soul.
To this faculty then life owes its origin in living
things; but
the being an animal owes its origin primarily to
sensation;
for beings that neither move nor change their place but
yet
possess sensation, we call animals and not merely living
things.
The primary sense, which exists in all, is touch; and just
as
the nutritive faculty can exist without touch or sensation of
any kind, so can touch exist without the other senses. The
"nutritive"
is our term for such part of the soul as is shared
even by plants, all
animals, however, evidently possessing the
sense of touch. The cause of
the presence of each of the two
aforesaid shall be told later. Now let
us only go so far as to
say that the soul is the source of the
[faculties] aforesaid,
and is defined by means of them, to wit: the
nutritive, the
sensory, the intellectual, the motor.[276] As to whether
each of
these is a soul or is a part of the soul; and if a part,
whether
in the sense that it is only separable by reasoning,[277]
or
locally as well--as to some of these points, it is not hard
to
see our way, but some present difficulties."[278]
If we turn
to Aristotle's treatise On Generation we find him dealing
with the relations
of the body to the nutritive soul, in virtue
whereof the body is alive; with
its relations to the sensory soul,
in virtue whereof it is an animal body;
and, finally, in man with
its relations to the intellectual soul. Of these
three kinds of
soul or parts of the soul, he concludes, the mind "is alone
divine;
for in the working thereof no bodily working is
involved."[279]
Only soul of this divine quality does he admit to be
separable from
body.[280]
The master has spoken. Now let the great
pupil speak. In the last
Exercise but one of his treatise On Generation,
Harvey says,
referring to the blood:--
"It assuredly contains the
soul first and foremost, not only
the nutritive, but the sensory soul as
well, and the motor. The
blood penetrates in all directions and is
present everywhere;
if it be taken away, the soul itself is made away
with
also and at once; so that the blood would seem to be wholly
indistinguishable from the soul or, at least, should be reckoned
the
substance of which the soul is the activity. The soul I aver
to be such
that neither is it body at all, nor yet entirely
without body, but comes
in part from without, in part is born
on the premises,[281] and in a
manner is part of the body;
in a manner, however, is the origin and
cause of everything
within the body of an animal, certainly of
nutrition, sense,
and motion, and hence, in like manner, of life and
death; for
whatsoever is nourished, that same is living, and _vice
versa_.
So, likewise, whatsoever is nourished abundantly, increases;
but
whatsoever too sparingly, dwindles; and whatsoever is
nourished
perfectly, keeps its health; whatsoever otherwise, lapses
into
disease. Therefore, as is the soul, so also is the blood to
be
reckoned the cause and author of youth and old age, of sleep
and of waking, and even of respiration also--especially in view
of this,
that in the things of nature the first instrument
contains within itself
an internal moving cause. Therefore, it
comes to the same whether one
say that the soul and the blood,
or the blood together with the soul,
or, if preferred, the soul
together with the blood, bring everything
within an animal to
pass."[282]
Only two years before these words
were published the aged Harvey had
said the following:--
"Nor
does the blood possess vigor, faculty, reason, motion, or
heat, as the
gift of the heart."[283]
A comparison of the foregoing passages from
Harvey with the
preceding passages from Aristotle makes it clear that, for
Harvey,
although the soul dwells no longer in its Aristotelian seat, it
is
no other than the Aristotelian soul which pervades the "principal
part"
of the body, the living blood of the Harveian circulation.
What proofs
does Harvey offer that the soul is in the blood? He has
offered already one
weighty piece of evidence noted by many from
of old in the chase, in
butchery, in sacrifice, in battle--the
evidence from fatal hæmorrhage. This
had been set forth nineteen
centuries before him by one of his Hippocratic
predecessors, who had
referred to the reasoning
"used by those
who say that the blood is the man; for, seeing
men slaughtered and the
blood running out of the body, they
conclude that the blood is the soul
of man."[284]
Presently Harvey himself shall tell us that in placing the
soul in
the blood he is consciously reaffirming one of the most ancient
of
beliefs; but he is far from basing his adhesion to it merely on
such
immemorial evidence, known to all, as the result of loss of
blood,
for he also adduces once more his own observations of the
early
embryo of the fowl, to prove not only the primacy of the blood
but
the presence of the soul therein. His testimony follows, and
in
reading it one must bear carefully in mind that in Harvey's time
no
clear scientific distinction had yet been worked out between
movements which
imply sensation, and movements, whether reflex or
not, which do not depend
upon consciousness. In his treatise On
Generation Harvey says:--
"For my own part I am sure from numerous experiments that not
only
motion is inherent in the leaping point,--which no one
denies--but
sensation also. For you will see this point thrown
into varied commotion
and, as it were, irritated, at any touch
whatever, even the slightest,
just as sensitive bodies in
general usually give evidence of sensation
by movements proper
to themselves. Moreover, if the injury be repeated
often, the
leaping point becomes excited and the rhythm and order of
its
pulsations disturbed. In like manner do we infer the
presence
of sensation in the so-called sensitive plant and in
zoophytes,
from the fact that when they are touched they draw
themselves
together as though taking it ill.... So there is no doubt
that
the leaping point lives, moves, and feels like an
animal."[285]
In a later part of the same treatise he says:--
"It is manifest that all motion and sensation do not proceed
from the
brain, since we plainly perceive the presence of motion
and sensation
before the brain has come into existence; what
I have related proves
that clearly sensation and motion dawn
forthwith in the first droplet of
blood in the egg, before a
vestige of the body has been formed.
Moreover, in that first
state of the structure or constitution of the
body which I have
called the mucilaginous, before any members are
discernible and
when the brain is nothing but limpid water, if the body
be only
lightly pricked it moves, contracts, and twists itself
obscurely
like a worm or caterpillar; so that it gives clear evidence
of
sensation."[286]
In another Exercise of the same treatise he
says:--
"It is evident also from the generation of the chick,
that
whatever the source of its life or the vegetative first cause
of
it may be, this had a prior existence in the heart.
Wherefore,
if the said first cause be itself the soul of the chick,
it
stands proved likewise that this had a prior existence in the
leaping point and the blood; seeing that we observe therein
motion and
sensation; for it moves and leaps like an animal. If,
then, there exist
in the leaping point the soul, which (as I
have taught in my account)
constructs for itself the rest of the
body, nourishes and increases it,
certainly from the heart as
from a fount the soul flows out[287] into
the entire body.
"So, likewise, if the egg be prolific because there
is a soul
in it, or (as Aristotle would have it) the vegetative part
of
the soul, it is clearly proved that the leaping point, in
other
words the generative part endowed with soul, springs from
the
soul of the egg, for nothing is the author of itself, and
that
the soul is transferred from the egg to the leaping point,
next
to the heart, and then to the chick."[288]
In still another
chapter of his treatise On Generation Harvey
says:--
"Nor does
the blood deserve to be called the original[289] part
and the principal
part, merely because in it and by it motion
and pulsation are
originated, but also because in the blood the
psychical heat first comes
into existence, the vital spirits
are generated, and the soul itself
inheres. For wherever the
immediate and principal instrument of the
vegetative faculty is
first found, there probably the soul also is first
present and
takes its origin thence; since the soul is inseparable from
the
spirits and the innate heat....[290]
"The life then
inheres in the blood (as we read also in Holy
Writ),[291] because
therein the life and the soul are manifest
first and fail
last....[292]
"It stands clearly proved that the blood is a
generative part,
the source of life, the first to live and the last to
die, the
primary seat of the soul; that in the blood, as in its
source,
the heat first and chiefly abounds and flourishes; and that
by
and from the blood all the other parts of the whole body are
fostered and obtain their life by means of the influx of heat.
Indeed,
the heat which accompanies the blood floods, fosters,
and preserves the
entire body, as I have demonstrated already in
my book on the motion of
the blood."[293]
Harvey's proof that the blood is "the first to live and
the last to
die," we have scanned already in an earlier chapter of this
paper.
In the next chapter of his treatise On Generation he
says:--
"No heat is to be found, either innate or inflowing, other
than
the blood, to be the soul's immediate instrument."[294]
On
the next page, after briefly making certain suppositions, he
says
further:--
"Why should we not affirm with equal reason that
there is soul
in the blood; and also, since the blood is the first
thing
generated, nourished, and moved, that out of the blood the
soul
is first evoked and kindled? Certainly it is the blood in
which
vegetative and sensitive workings first come to light; in
which
heat, the primary and immediate instrument of the soul, is
innate; it is the blood which is the common bond of body and
soul, and
in which as a vehicle soul flows into all parts of the
whole
body."[295]
But no matter how far on high the blood may have been exalted
by
Harvey the physician and psychologist, it is still subject to
the
lancet of Harvey the clinician, the heir of Hippocrates; for in
his
treatise On Generation, in the same Exercise with the
foregoing
passage, occurs the following:--
"While I assert that
the seat of the soul is in the blood,
first and foremost, I would not
have the false conclusion drawn
from this that all blood-letting is
dangerous or hurtful; nor
have it believed, as the multitude believes,
that just to the
degree that the blood is taken away does the life pass
away at
the same time, because holy scripture has placed the life
in
the blood. For it is known from everyday experience that the
taking of blood is a wholesome aid against very many diseases
and is
chief among the universal remedies; seeing that depravity
of the blood,
or excess thereof, is at the bottom of a very
great host of diseases;
and that the timely evacuation of
blood often brings exemption from most
dangerous diseases and
even from death itself. For just to the degree
that the blood
is taken away as our art prescribes, is an addition made
to
life and health. This very thing has been taught us by
Nature,
whom physicians set themselves to imitate; for Nature
often
makes away with the gravest affections by means of a large
and critical evacuation by the nares, by menstruation, or by
hæmorrhoids."[296]
Not only does Harvey affirm that "the soul is in the
blood" and, as
we have seen, appeal to observation and experiment in support
of
this doctrine; but he refers to those who had believed it before
him,
and maintains it against Aristotle's express denial. We
have heard him
testify as an observer; now let us hear him deal
historically and polemically
with the doctrine in question. Quite
simply, in the final work of his old
age, does the veteran tell of
the wide acclaim which at last has greeted his
discovery of the
circulation--the most modern and revolutionary achievement
of his
time. The contrast is startling when, in the same breath, with
equal
simplicity he proceeds formally to identify his own latest view
of
the significance of the circulating blood with a doctrine which
had
been ancient in ancient times; a doctrine not only found in the
Old
Testament, but held by Greek thinkers who were historic figures
even
in the eyes of Aristotle. In his treatise On Generation
Harvey
says:--
"I see that the admirable circulation of the blood
which I
discovered long ago has proved satisfactory to nearly all,
and
that so far no one has made any objection to it which
greatly
calls for answer. Therefore, if I shall add the causes
and
uses of the circulation and reveal other secrets of the
blood,
showing how much it conduces to mortal happiness and to
the
welfare of soul as well as body, that the blood be kept pure
and sweet by a right regimen, I truly believe that I shall do a
work as
useful and grateful to philosophers and physicians as
it will be new;
and that the following view will seem to nobody
so improbable and absurd
as it formerly seemed to Aristotle,
viz.: that the blood, a domestic
deity as it were, is the very
soul within the body, as Critias and
others thought of old;
they 'believing that capacity for sensation is
the most special
attribute of the soul, and exists because of the nature
of the
blood.' By others again that which derives from its own
nature
the power of causing motion was held to be the soul; as
Thales,
Diogenes, Heraclitus, Alcmæon, and others believed.[297] It
is
made plain, however, by very numerous signs that both
sensation
and motion inhere in the blood in spite of
Aristotle's[298]
denial."[299]
We have noted with Harvey the
doctrine of Leviticus, which still
rules the procedure of the Jewish butcher;
and as we look backward
to Athens across the centuries, we find Plato putting
this question
into the mouth of Socrates: "Whether it be the blood with
which
we think, or air, or fire, or none of these."[300] In Hellas
this
doctrine had been well known before Plato, Socrates, or the
Hippocratic
writers, one of whom we have found referring to it.
The Sicilian Greek
Empedocles, a philosopher and physician born at
Acragas about 495 B.C., is
said to have held, long before Aristotle,
that the heart is the part formed
first in the embryo;[301] and
in a line of verse which has come down to us
Empedocles said: "In
the blood about man's heart is his understanding."[302]
Empedocles
is reported to have held to this because in the blood "are
most
perfectly blended the elements of the parts,"[303] that is,
earth,
water, air, and fire.
The accomplished and wicked Athenian
Critias, to whom Harvey refers,
was that chief of the Thirty Tyrants who was
slain in 403 B.C., four
years before Socrates drank the hemlock and nineteen
years before
the birth of Aristotle. With the opinion of "Critias and
others"
Harvey, as we have seen, identifies his own view that the soul is
in
the blood. They held capacity for sensation to be the mark of soul
and
to be due to the nature of the blood; and Harvey's statement
of these views
is a literal quotation from the second chapter of
the first book of
Aristotle's treatise On Soul, which Harvey cites.
This chapter is also the
source of his summary and not quite exact
reference to those other ancients
who, as he avers, held spontaneous
motor power to be the mark of soul--a
power which Harvey unites in
the blood with capacity for
sensation.[304]
In the aforesaid chapter of Aristotle's work On Soul
this
philosopher had curtly reckoned among the "cruder" thinkers those
of
his predecessors who, "like Critias," had held the soul to be
blood. Harvey
notes the master's condemnation, but, as we have seen,
stoutly ranges himself
with the condemned ancients and affirms that
sensation is inherent in the
blood despite the master's denial.
It is strange to note how the London
physician seems less modern,
for the moment, than the ancient philosopher of
Athens. Aristotle,
like a man of to-day, treats the blood simply as the
immediate
food of the tissues, noting expressly that it has "no feeling
when
touched in any animal, just as the excrement in the belly has
no
feeling."[305] Harvey deals as follows with this obvious truth
in
dealing with the question whether the blood can properly be reckoned
a
part of the body in the technical sense. He says:--
"At this time I
will only say this: Even if we concede that
the blood does not feel,
nevertheless, it does not follow that
it is not a part of a sensitive
body and the principal part at
that."[306]
We do not know that
Aristotle ever saw or noted in the dying auricle
the "undulation" by which
Harvey was so much impressed; but we
have seen that, like Harvey, Aristotle
treated of the development
of the early embryo within the hen's egg and that,
like Harvey,
he laid special stress upon the red "leaping point."
Aristotle
concluded that the heart is the first generated living part,
that
it makes and will make throughout life the blood which it
contains
and distributes. In the heart he fixed the focus of the innate
heat
and, knowing nothing of the nervous system, he fixed in the heart
the
seat of the soul also. Harvey came to the conclusion that the
blood is the
first generated living part; that it has made the heart
which contains it and
which keeps it circulating and which it will
nourish throughout life, as it
will the other parts. In the blood
itself he placed the innate heat and,
though he knew the nervous
system, he placed in the circulating blood the
seat of the soul,
which animates every part.
"We conclude," he
says, "that the blood lives and is nourished
of itself and in no wise
depends upon any other bodily part
either prior to or more excellent
than itself."[307]
Thus the rigorously proved and demonstrated
circulation of the
blood was linked by its discoverer with the speculations
of remote
antiquity.
As we have seen, the use of the circulation
became to Harvey a
life-long subject of speculation, because this discovery
had raised
questions which no man could answer before the finding of
oxygen.
How obscure a problem Harvey found the functions of the blood to
be,
is nowhere better indicated than where he says in his old
age:--
"So with better right one might maintain that the blood
is
equally the material of the body and its preserver, but not
merely its food. For it is well known that in animals that
perish of
hunger, and also in men who waste away and die, there
is abundance of
blood to be found in the vessels, even after
death."[308]
Is it
the least part of Harvey's glory that his mind had cloven its
way through
long-lived beliefs to a truth which he could demonstrate
but could not
explain, and which seemed to other eminent men to be
no truth, because too
senseless to be true?[309] When he finally
broke with the ancient master,
Harvey could not be content with
sheer ignorance; and the same observations
and experiments which
led him out of Aristotelian error misled him into error
quite as
grave. As to the venerable doctrine regarding the seat of the
soul,
which he at last embraced upon grounds now seen to be too
slender,
was not this doctrine one with which the Harveian
circulation
could harmonize well and which in turn could greatly glorify
the
circulation? Let us pause, think, and read
further.
CHAPTER X
THE BLOOD THE INNATE
HEAT
The latter part of Harvey's treatise On Generation is devoted
to
that of the mammal; but the treatise does not end with the end of
this
subject, for from his account of generation the author turns
abruptly to
append two Exercises on other topics. The first of these
two is entitled "On
the Innate Heat," and the second, which is very
brief, is entitled "On the
Primitive Moisture."
The Exercise On the Innate Heat is Harvey's express
and polemical
contribution to this subject, which had been much discussed
both
during and before his time;[310] a subject with which the
famous
discoverer deals roundly by maintaining that the innate heat
is
neither more nor less than the circulating blood. So the last words
as
to the significance of the circulating blood which he wrote for
publication
are contained in this Exercise. It begins as follows:--
"Since
mention is often made of the innate heat, I propose now,
by way of
dessert, briefly to discuss the same and the primitive
moisture also;
and this the more willingly that I see there are
many who take the
greatest delight in those names and yet, in
my judgment, comprehend but
little of the things themselves.
Truly, there is no need to seek for any
spirits distinct from
the blood, or to bring in heat from elsewhere, or
call gods
upon the stage and load philosophy with fanciful
opinions;
for what we so commonly would fetch from the stars is born
at
home. In truth, the blood alone is the innate warmth, or the
first-born psychical heat;[311] as is proved excellently well
by our
observations of the generation of animals, especially of
the chick in
the egg; so that it were superfluous to multiply
entities. Indeed, there
is nothing to be met with in the animal
body prior to the blood, or more
excellent; nor are the spirits
which they distinguish from the blood to
be found anywhere
separate from it; for the very blood itself, if
without spirits
or heat, does not deserve the name of blood, but of
cruor....
"Scaliger, Fernelius, and others lay less weight on
the
extraordinary endowments of the blood and imagine other
spirits to exist, aerial or ethereal or composed of substance
both
ethereal and elemental, constituting an innate heat more
excellent and
more divine, as it were; and these spirits
they believe to be the soul's
most immediate instrument, the
fittest for every use. They rely
especially upon this argument,
viz.: that the blood, being composed of
elements, can exert
no activity beyond the powers of the elements or of
bodies
consisting of a mixture thereof. Therefore, they imagine
a
spirit, another innate heat, of celestial origin and nature,
to wit: a body most simple, most subtile, most fine, most
mobile, most
swift, most clear, ethereal, and sharing in the
quintessence. Nowhere,
however, has any such gift of spirit been
demonstrated by them, nor that
the same acts beyond the powers
of the elements, or accomplishes greater
works than could the
blood alone. As for us who use our senses to guide
us in the
scrutiny of things, nowhere have we been able to find
anything
of the kind. Furthermore, there exist no cavities
destined
for the generation or preservation of these spirits, or
even
assigned thereto by the persons aforesaid."[312]
A little
farther on we read:--
"I deem it, however, most wonderful that
spirits which draw
their origin from heaven and are adorned with such
surpassing
endowments should be nourished by our common and elemental
air;
especially seeing that their advocates hold that none of
the
elements can act beyond its own powers....[313] What need
then
is there, say I, of that foreign guest, ethereal heat,
since
all can be accomplished by the blood, even as by it; while
from the blood the spirits cannot withdraw a hair's breadth
without
perishing? Most assuredly nowhere do they wander or
penetrate as
separate bodies without the blood. For whether it
be said that they are
generated, nourished, and increased from
the thinner part of the blood,
as some believe, or from the
primitive moisture, as others hold; yet it
is confessed that
they are never found outside the blood but forever
cleave to
the same as to their sustenance, as flame does to oil or
to
a wick. Wherefore their tenuity, subtility, mobility, and so
forth, confer no greater advantage than does the blood which
they
continually accompany. It follows that the blood suffices
and is fit to
be the immediate instrument of the soul, since the
blood is present
everywhere and most swiftly permeates hither
and
thither."[314]
The two opponents named by Harvey were not his
contemporaries, but
worthies of the Renaissance who had written about one
hundred years
before the publication of his treatise On Generation and had
died
before he was born. The Italian physician Julius Cæsar Scaliger
had
written learned commentaries on Aristotle, as well as other
works; and the
Frenchman Jean Fernel, physician to King Henri II of
France, had taught
anatomy at Paris and had been a medical writer
of importance. Each of these
two authors was nearly sixty years
of age in 1543, in which memorable year
were first published the
revolutionary writings of the aged astronomer
Copernicus and of
the young anatomist Vesalius, in the second year after the
death
of the hardy innovator Paracelsus. Such were the men against
whose
doctrines Harvey was impelled in his old age to launch his
vigorous
criticism, in order to clear the way for his own doctrine of
the
preeminence of the blood. What can we workers of to-day make of
their
opinions, which were living for Harvey but now are so deeply
buried?
Test-tube and balance, telescope, spectroscope, microscope,
manometer, and
the rest, have served their purpose so well since
Harvey's time that even he,
one of the foremost worthies of science,
must seem merely to beat the air
with words in his last message to
us, unless we can recover his standpoint.
Happily he himself shall
attempt to clarify the meaning of his polemic by
setting before us
certain words of Aristotle, embodying far-reaching
speculations as
to body and soul in relation to the universe. Yet we shall
find
these not easy to understand.
Let Harvey continue his criticism
of his predecessors. He says:--
"But while they believe that there
are found in animals spirits
and ultimate or primitive nourishment, or
something else, which
acts beyond the powers of the elements more than
does the blood,
they do not seem to have a sufficient grasp of what it
may be to
'act beyond the powers of the elements'; nor have they
rightly
interpreted the words of Aristotle where he says:[315]
'The
virtue or potency of every soul[316] seems to be associated
with
a body[317] other than the so-called elements and more
divine.'"
And a little farther on:[318]--
"'For there exists
in the semen of all [animals] that which
makes their semen generative,
the so-called heat. Yet this is
not fire, nor any such power, but the
spirits[319] included
in the semen and in foaminess, and in the spirits
the nature
which is analogous to the element of the stars.[320]
Wherefore
fire generates no animal, nor does anything [animal] appear
in
process of formation in that, whether moist or dry, which is
undergoing the action of fire;[321] whereas the heat of the sun
and that
of animals--not only that [which acts] through the
semen,[322] but also,
should there occur some excretion of a
different nature[323]--even this,
too, possesses a life-giving
principle. It is patent, then, from such
[facts] as these that
the heat in animals is not fire and does not take
its origin
from fire.'[324]
"I, too, would say the same, for
my part, of the innate heat
and the blood, to wit: that it is not fire
and does not take
its origin from fire, but is associated with another
body and
that more divine, and, therefore, does not act by reason
of
any elemental faculty; but, just as there exists in the semen
something which makes it generative and exceeds the powers of
the
elements in building an animal--to wit, spirits, and in the
spirits a
nature analogous[325] to the element of the stars--so
likewise in the
blood there exist spirits or some power which
acts beyond the powers of
the elements, a power very conspicuous
in the nourishing and preserving
of the several parts of an
animal; and in the spirits and blood exist a
nature, yea, a
soul, analogous to the element of the stars. It is
manifest,
therefore, that the heat in the blood of animals during life
is
not fire and does not take its origin from fire; and this is
taught excellently well by our own observations....[326]
"Therefore,
those who assert that nothing composed of the
elements can work beyond
the powers of these, unless it be
associated at the same time with
another body and that more
divine, and maintain, therefore, that the
spirits aforesaid
consist in part of the elements, in part of some
ethereal and
celestial substance--truly, such persons seem to me to
have
drawn their conclusions ill. For you shall find scarcely
any
elemental body which, when in action, will not exceed its own proper
powers." |
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