Physiological Researches on Life and Death

by Xavier Bichat

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.

[CHAPTER V.]
OF THE INFLUENCE OF THE DEATH OF THE HEART AS TO THE PRODUCTION OF GENERAL DEATH.

Whenever the heart ceases to act, general death is produced in the following manner:—1st. For want of excitement the cerebral actions are annihilated, and consequently an end is immediately put to all sensation, locomotion, and utterance. Besides, for want of excitement on the part of the blood, the organs of these functions would cease to act, even supposing that the brain were to remain unaffected, and exert upon them its accustomed influence. Thus the whole of the animal life is suddenly suspended, and at the instant of the death of the heart, the individual is dead to what surrounds him.

The interruption of the organic life, which has commenced by the death of the heart, is produced at the same time by that of the lungs. The brain being dead, the mechanical functions of the lungs must cease: the chemical functions of the lungs must cease also, for want of the materials on which they are exerted: the latter are directly interrupted, the former through the medium of the brain.

After this the progress of death is gradual. The secretions, the exhalations, the nutritive actions are put an end to. The latter are first arrested in those organs which receive the more immediate impulse of the blood, because in these, such impulse is necessary to the performance of the functions. The paler organs are less dependent on the influence of the heart, and consequently must be less affected by the cessation of its action.[73]

In the successive termination of the latter phenomena of the internal life, the vital powers continue to subsist for some time after the loss of the functions: thus, the organic sensibility, and the sensible and insensible contractilities survive the phenomena of digestion, secretion, and nutrition.[74]

The vital powers continue to subsist in the internal life, even when the corresponding powers of the animal life, have suddenly become extinct: the reason is plain: the power of perceiving and moving organically does not suppose the existence of a common centre; for the animal perceptions and motions, the action of the brain is requisite.

The phenomena of death are concatenated in the above order in all aneurismal ruptures, in all wounds of the heart or larger vessels, in all cases of polypi formed in the cardiac cavities,[75] of ligature artificially applied, of compression exercised on the parietes of the heart by humours, abscesses, &c. &c.

It is in this manner also that we die from sudden affections of the mind. The news of a very joyful, or a very melancholy event, the sight of a fearful object, of a detested enemy, of a successful rival, are all of them causes capable of producing death. Now in all these instances, it is the heart, which is the first to die, the heart, whose death successively produces that of all the other organs, the heart, on which the passion is exerted.

And hence we are led to some considerations on syncope, an affection exemplifying in a less degree the same phenomena, which in a greater one, is offered us in cases of sudden death.

The causes of syncope are referred by Cullen to two general heads: Of these there is one set which according to him affect the brain, another set which affect the heart. Among the first, he places the more violent impulses on the mind, and various evacuations, but it is easy to prove, that the brain is only secondarily affected in syncope produced by passion, and that it is the heart, whose functions in all these cases are the first to be interrupted. The following considerations, if I am not mistaken, will leave but little doubt on this head.

1st.—I have proved, in speaking of the passions, that they never affect the brain in the first place; that the action of this organ, in consequence of their development, is only secondary, and that every thing relating to our moral affections has its seat exclusively in the organic life.

2dly.—The phenomena of syncope when produced by lively emotion, are similar in every respect to those of syncope, the effect of polypi or dropsy of the pericardium, but in the latter, the affection of the heart is the primary one, and should in consequence be the same in the former sort of syncope.

3dly.—At the moment when syncope takes place, we feel the attack at the heart, and not in the brain.

4thly.—In consequence of lively passions, which may have occasioned syncope, we find that the heart and not the brain becomes diseased, nothing is more common than organic affections of the former from sorrow, &c. The different sorts of madness, which are produced by the same cause, for the most part have their principal seat in some of the viscera of the epigastrium, and in such case, the irregularity of the cerebral action is the sympathetic effect of the profound affection of the internal organ.[76]

5thly.—I shall prove hereafter, that the cerebral system does not exert any direct influence over that of the circulation; that there is no reciprocity between the two, and that the changes of the first are not followed by similar changes in the second, however much the changes of the second may modify the first. Destroy all nervous communication between the brain and the heart, and the circulation will go on as usual; but if the vascular communications be intercepted, the cerebral action vanishes at once.

6thly.—Palpitations and other irregular movements of the heart are often the effect of the same causes, which in some individuals are the occasion of syncope. In such cases, it is easy to discover the seat of the affection, and such smaller effects of the passions on the heart, are very well calculated to throw light upon the nature of the greater.[77]

From these many considerations, we may conclude that the primitive seat of the attack in syncope, is the heart, which does not cease to act, because the action of the brain has been interrupted, but because it is the nature of some of the passions in such way to affect it, the brain at the same time, suffering a temporary death, because it no longer receives the fluid, which is necessary to its excitement. The nature of syncope is well enough illustrated, by the vulgar expression of being sick at heart.

It is of no importance to our present purpose, whether syncope depend on polypi, on aneurism, or be the result of some violent emotion. The successive affection of the organs is always the same. They die for the moment in the same way, as they really perish when the heart is wounded, or a ligature put upon the aorta. In the same manner also are those sorts of syncope produced, which succeed after any great evacuation of blood, pus or water. The heart is affected from sympathy, the brain for want of its excitant.[78]

Those cases of syncope which are occasioned by peculiar odours, by antipathies, &c. appear also to be attended with the same progression of symptoms, though their character be much less easily understood. There is a great difference between syncope, asphyxia, and apoplexy, in the first it is by the heart, in the second by the lungs, in the third by the brain that begins the general death of the body.

Death, as it happens in consequence of disease, in general exemplifies a concatenation of these different symptoms. The circulation, respiration, or cerebral action cease, the other functions are afterwards interrupted of necessity, but in these sorts of death, it rarely happens that the heart is the first to die. This however is sometimes the case. After long continued suffering, great suppuration, and sometimes, in dropsy, certain fevers, and gangrenes, one fit of syncope comes on after another, at last a longer one succeeds, and the patient dies, but whatever be the part affected, whatever the diseased viscus or organ, whenever the phenomena of death commence by the heart, they succeed each other as we have described them to do in sudden death, from lesion of that organ. In other cases, the heart is the last to act, is the ultimum moriens.

In general, in morbid affections, we much more commonly observe the ingress of death to be made by the lungs, than either by the heart, or the brain.

Whenever disease is terminated by syncope, the lungs are found to be almost empty, and if not affected by any organic disease, are collapsed, occupy a part only of the cavity of the thorax, and are of their natural colour.

The reason of this anatomical fact is simple. The circulation which has been suddenly interrupted, has not had time to fill the vessels of the lungs, as happens when death begins, by affecting the lungs or the brain. The truth of this fact I can vouch for, having frequently ascertained it by dissection, and in general, as often as death commences by the heart, or the larger vessels, such vacuity of the lungs may be considered as universal.

I have remarked it in the bodies of persons who have died from great hemorrhage from wounds or aneurismal rupture and violent passion, as well as in those who have suffered by the guillotine. The same phenomenon may be seen, by inspecting the lungs of any animal, which is killed in our butcheries.

In killing the animal slowly by the lungs, that organ might be filled with blood. Its taste would then be different from that which it naturally possesses, and resemble that of the spleen. Our cooks know well how to take advantage of that state of infiltration in which the latter viscus is generally found.