OF THE INFLUENCE OF THE DEATH OF THE HEART OVER THAT OF ALL THE
ORGANS.
I shall divide this chapter, as the preceding one, into two
sections. In the first I shall examine, how the death of the
red-blooded heart, in the second how the death of the black-blooded
heart, is the cause of the death of all the parts of the body.
I. _On the death of the red-blooded heart, and how that of the
organs is occasioned by it._
All the functions belong either to the animal, or to the organic
life. Hence the difference of their classes. Now the death
of those of the first class, in consequence of lesions of the
red-blooded auricle and ventricle, is caused in two ways, and
first, because the brain in such case is rendered inert from want
of impulse, and can neither have sensations, nor exercise an
influence over the locomotive and vocal organs.
Accordingly, all this order of functions is stopped, as when the
encephalic mass has experienced a violent concussion. It is in this
way that a wound of the heart, or the bursting of an aneurism,
annihilate all our relations with external objects.
So strict a connexion between the movement of the heart, and the
functions of the animal life, is not observable in those animals
in which the brain, in order to act, does not require the habitual
stroke of the blood. Tear away the heart of a reptile, or tie its
large vessels, and it will continue for a long time to move and
have sensations.
Besides, supposing even that the action of the brain were not to be
suspended from lesions of the red-blooded heart, the animal life
would not, on that account, be the less put an end to; because
to the exercise of the functions of this life, is attached as a
necessary cause, the excitement of its organs by the afflux of
blood into them: now this excitement, both here and every where
else, depends upon two causes.--1st, On the movement impressed,
and 2dly, On the nature of the blood. At present I shall only
examine the first mode of influence; the latter will come under our
consideration, when we speak of the lungs.
Habitual motion is necessary to all the parts of the body alike, is
a condition essential to the functions of the muscles, the glands,
the vessels, and the membranes, &c. But this movement, which is
partly derived from the heart, is very different from that which
is communicated by the blood to the brain.
The latter organ receives an impulse by which the whole of its mass
is visibly raised, an impulse, in the intermission of which the
whole of its mass subsides. On the contrary, the interior movement,
by which its particles are affected, is scarcely marked at all: and
this depends upon the smallness and the delicacy of the vessels by
which its substance is penetrated.
The contrary of this appearance is observed in the movement
occasioned in the other organs by the influx of the blood into
them: we see them neither rise nor subside; there is nothing
like a general impulse made upon them, because, as I have
said, such impulse is lost from the little resistance of the
surrounding parts. On the contrary, they are penetrated by vessels
of considerable magnitude, which create an intestine motion,
oscillations, and impulses adapted to the actions of the tubes,
lamellæ, or fibres, of which they are composed. This difference
of movement may be easily conceived, by comparing the manner in
which the brain on the one hand, and on the other the liver, the
spleen, the muscles, or the kidneys receive their blood; indeed it
is requisite that the brain should be distinguished from the other
organs, in the manner of receiving its impulses, because it is
enclosed in a case of bone, and consequently abstracted from the
thousand other causes of agitation, to which the other parts of the
body are exposed.
For we may remark, that all the other organs have about them a
number of agents, which are destined to supply the place of that
general impulse, which is wanting to them on the part of the heart.
In the breast, the intercostals and diaphragm are continually
rising and falling; the lungs and the heart are successively the
seat of a dilatation and contraction. In the abdomen, there is an
uninterrupted agitation produced, by the influence of respiration
upon its muscular parietes; an incessantly variable state of
the stomach, intestines and bladder. Lastly, from the various
contractions of the muscles, the limbs have a still more evident
cause of movement.
Nevertheless, it is probable that every one of the organs, as well
as the brain, has a general though obscure movement impressed upon
it, from the pulsation of the arteries; and hence, perhaps, we have
the reason, why the greater number of the viscera, receive the
impulse of the red blood upon their concave surfaces, as may be
seen in the kidneys, the liver, the spleen, and the intestines. By
such disposition, the impulse of the heart is less divided.[70]
From what has now been said, we may add another reason to that
which we have before given, for establishing in what way the
functions of the animal life are interrupted from cessation of
action in the red-blooded heart. We may now also begin to explain
the same phenomenon in the organic life. The reason of such
interruption in both the lives is the same. It is as follows:
1st. In the case of death affecting the red-blooded heart; the
intestine movement, which proceeds from the manner in which the
arteries are distributed within the substance of all the organs,
both of the one and the other life, is suspended; hence there
exists no farther cause of excitement for the organs: they must
consequently die.--2dly. The causes of the more extensive and
general movements of the organs are abstracted; for almost all
these causes depend upon the brain. We respire and move, only
while the brain is alive: but as the brain must be in a state of
collapsus, as soon as it ceases to receive the impulse of its
blood, its influence must be evidently annihilated.
Hence it follows, that the heart exercises over the different
organs two modes of influence; the one direct and immediate, the
other indirect, and made through the medium of the brain, so that
the death of the organs in consequence of the death of the heart,
is immediate or mediate.
We have sometimes examples of partial death, analogous to this sort
of general death. Thus, when the circulation is impeded in a limb,
and the red blood no longer distributed to its parts, such parts
become at first insensible and paralytic, then gangrenous. The
operation of aneurism furnishes us with too many instances of this
phenomenon, which by ligature, may be produced also in the living
animal. Undoubtedly the principal cause of death in these cases, is
the want of that stimulus which it is the business of the particles
of the red blood to create, in contradistinction to those of the
black blood, but the absence of the intestine movement in question,
is by no means a less real cause of such death.
As for the interruption of the nutritive process, it cannot be
admitted as a cause of the symptoms which succeed after the
obliteration of a large artery. The slow, the gradual, and
insensible way, in which this function is performed, does not
accord with the sudden and instantaneous production of those
symptoms, especially as they affect the animal life; for this is
annihilated in the limb at the very instant when the blood ceases
to flow into it, just in the same way as it is, when by the section
of its nerves, the influence of the brain is abstracted.[71]
Besides the preceding causes, which, when the heart is dead,
suspend in general the whole of the animal and organic functions;
there is another cause of death which especially affects the
greater number of the latter, such as the processes of nutrition,
exhalation, secretion, and therefore digestion, which is only
performed by means of the secreted fluid. This cause of death to
which I refer, consists in the necessary stop which is put to these
different functions, in consequence of their no longer receiving
the materials upon which they are exercised. Nevertheless, such
term arrives by degrees only, because they receive the materials
on which they act, from the capillary, and not from the general
circulation. Now the capillary circulation, is only subject to the
influence of the insensible contractile powers of the parts in
which it is performed; and is exercised independently of the heart,
as may be seen in the greater number of reptiles, where the heart
may be taken away, and the blood be notwithstanding observed to
oscillate for a long time afterwards in the minuter vessels.[72]
It is manifest, then, that whatever quantity of blood is left in
the capillary system at the period of the death of the heart, will
for some time afterwards be sufficient to keep up the functions
in question, and that such functions in consequence will only
gradually cease.
The following is a general view of the manner in which the
annihilation of all the functions succeeds to the interruption of
those of the heart.
The animal life is terminated--1st, Because the organs of which
it is composed, are no longer excited without, by the movement of
the neighbouring parts, nor within, by the blood.--2dly, Because
the brain, from want of excitement, can no longer be a cause of
excitement.
The organic life is terminated--1st, Because, as in the animal
life, there is a want of external and internal excitement for its
different viscera.--2dly, Because there is a want of the materials
on which its functions are particularly exercised.
There are a number of other considerations, however, besides those
which we have mentioned, which prove the reality of the excitement
of the organs, from the movement communicated to them by the blood,
as well as the reality of the cause, which we have asserted to be
that of their death, when such excitement ceases.
For, 1st.--The organs which are penetrated only by the serum of the
blood, such as the hair, the nails, the tendons, and cartilages,
enjoy a less degree of vitality, and a less energetic action, than
those in which the blood is made to circulate, either immediately
by the heart, or by the insensible contractile powers of the parts
themselves.
2dly.--When the white organs are inflamed, they receive an
augmentation of life, a superabundance of sensibility, which
frequently put them on a level in many respects with those organs,
which in their natural state are endowed with the highest degrees
of life and sensibility.
3dly.--Those organs which habitually receive the influx of the
red blood, when inflamed, exhibit, in every instance, a local
exaltation of the phenomena of life. In the two preceding
instances, it is true, indeed, that the change of vital powers,
precedes in point of time, the change which is made in the
circulation; the organic sensibility of the part, has been
augmented before the blood is carried thither in greater quantity;
but afterwards it is the afflux of such increased quantity
of blood, which keeps up the unnatural action which has been
established. A determined quantity of blood in the ordinary state
of the part, is necessary to the maintenance of that state; but
when the part receives a double or triple increase of energy, its
excitant also must be doubled or tripled; for in the exercise of
the vital powers, there are always three things to be remarked; the
power inherent in the organ; the excitant which is foreign to it;
and the excitement which is the product of the two.
4thly.--It is doubtless, for this reason, that the organs to which
the blood is habitually carried by the arteries, enjoy a degree
of life, proportionate to the quantity of fluid by which they are
injected. Such phenomenon may be observed in the glans penis, in
the corpora cavernosa, in the nipple, in the skin of the face, and
the actions of the brain, whenever the blood is directed with
impetuosity towards them.
5thly.--The whole of the circulatory system, is thrown into greater
action from the exaltation of the whole of the vital phenomena,
just in the same way as the particular circulation of any part
is augmented, when the particular phenomena of the life of that
part are increased. The use of spirituous liquors, and spices to
a certain quantity, is followed for a time by a general increase
of energy in the powers of the system. The access of inflammatory
fever will double and triple the intensity of life.
In these considerations I have only regarded the movement which is
communicated to the organs by the blood. In another place I shall
call the attention of the reader to that species of excitement,
which is produced by the nature of the blood, by the contact of
its component particles when in a state of oxydation or otherwise,
with the different parts of the body. The reflections which I have
offered, will be amply sufficient to convince us how much the
blood, independently of the materials which it conveys with it, by
its simple influx, is necessary to the activity of the organs, and
consequently how much the cessation of the functions of the heart,
must influence the death of the organs.
FOOTNOTES:
[70] It should not be lost sight of, that all this discussion
turns upon the application of a principle which is by no means
proved: viz. that the different organs, in order to exercise their
functions, require to be agitated by a partial or general motion.
We have already made it appear, that as it respects the brain,
this jarring of the whole mass, to which Bichat attributes so much
importance, appears to be a circumstance purely accidental from
the entrance of the arterial blood. The same may be said of the
oscillatory motion produced in the other organs by the pulsation of
the ultimate arterial ramifications.
[71] When the passage of the arterial blood to a muscle is stopped,
a more or less complete numbness soon takes place; and this
effect is too sudden to be attributed to the want of nutrition;
and as certainly it is not owing to the want of agitation by the
pulsations of the small arteries; for if, the artery is left
free, and a ligature is applied upon the vein, the pulsations are
increased rather than diminished and yet the numbness appears as
quick as before.
When the muscle has been a long time without receiving blood,
gangrene seizes upon it; and this can then be attributed, in
great measure, to the want of nutrition. The diminution of the
temperature, which necessarily takes place in an organ in which the
blood is not renewed, must also contribute to this disorganization.
[72] We know that the blood pushed into the arteries distends the
parietes of these vessels, and brings into action their elasticity;
now, after the heart has ceased to act, these parietes, by
contracting, can impart, for some instants, an oscillatory motion
to the fluid contained in their cavity.