Physiological Researches on Life and Death

by Xavier Bichat

2dly, If the par vagum and the great sympathetic be divided at the same time on both sides of the neck, the animal will die after a certain time, and much in the same way, as when only the par vagum is divided.

3dly, When we divide the sympathetic nerve in the neck, we do not deprive the lungs of the nerves which come from the first thoracic ganglion; now these nerves may contribute to keep up the action of the lungs, since, as I have said, each ganglion is a nervous centre, capable of emitting its own peculiar irradiations, independently of the other centres, with which it communicates.

But whether the nerves, which are derived from the first thoracic ganglion, do really assist the functions of the lungs, I have not been able to ascertain by experiments on the nerves themselves, for such is the position of the first thoracic ganglion in most animals, that it cannot be taken away without doing so much injury to the parts as would kill the creature, or throw it into such agitation, as wholly to confound the phenomena of which we are in search, with those of a general distress and trouble. From analogy, however, and from the destruction of other ganglions, by which the internal organs are supplied, we should not have a right to suppose that the lungs would cease to act, when the ganglion in question is destroyed.

Besides, the following reasons appear to me to prove unquestionably, the principle which I advance. If great lesions of the brain have the effect of suddenly interrupting respiration, because this organ can no longer influence the lungs by means of the nerves, which come from the first thoracic ganglion, it is evident that if all communication between the brain and this ganglion be taken away, such influence must cease, and respiration be suspended; but if we divide, as Cruikshanks has done, the spinal marrow on a level with the last of the cervical vertebræ, the animal will continue to live and breathe for a length of time, notwithstanding the want of communication between the brain and the lungs, by means of the first thoracic ganglion. From the above experiments, we may conclude, that the brain does not exercise any direct and actual influence over the lungs, and consequently that other causes must be sought for, if we mean to account for that sudden and instantaneous cessation of the functions of the latter of these organs, when those of the former are suspended.

There exists, notwithstanding, a phenomenon which seems to cast some doubt upon the conclusion which I have deduced, and in the principle which it establishes. I speak of the sudden difficulty of respiration, and that impeded circulation which are occasioned by violent pain. This distress appears to indicate that the heart and the lungs are dependent immediately upon the brain; for the distress is in the brain, say the greater number of authors, and the affection of the heart and lungs, a consequence of the reaction of the brain; but here let it be remembered, that almost all pain is made up, first of sensation, and secondly of some emotion, passion or affection.[111] Now as I have proved at length, in the former part of this work, all passion and emotion have their seat in the internal viscera, and thus it will appear, that the trouble which in such case is felt in the heart and lungs, does not depend upon the brain for its cause, but is the immediate effect of the passion, or emotion, which accompanies the sensation. The following considerations will bear me out in this conclusion.

1st, In many instances the dyspnœa and impeded circulation, precede the pain. Examine the thorax, and place your hand upon the heart of a man about to undergo an operation, and you will be easily convinced of this truth.

2dly, There is sometimes a manifest disproportion between the sensation of pain, and the distress which is experienced about the heart, and in breathing. I have known the operation of cutting away the prepuce immediately fatal. Now in this case, it surely could not be pain which killed the man.

3dly, There are many persons who are capable of supporting violent pain, with resolution. Place your hand upon the heart of such persons, and no agitation whatever will be felt there. Nevertheless, their perception of pain must be what it is in other persons.

4thly, In the course of an operation, we are not to judge of the patient’s state of mind, from his cries, or silence. This sign is very deceitful; because a man may be sufficiently master of himself to overpower the influence of his internal organs. We must examine the heart and lungs; their functions, if I may allow myself the expression, are the thermometer of the affections of the mind. It is not without reason, that the actor who plays the part of a courageous man, takes hold upon the hand of him whom he wishes to set at ease, and lays it on his heart. The exterior movements of the passions, are not a fair criterion of the inward feelings of the individual, for these movements may be feigned as well as real: feigned if they originate in the brain: real if they have their sources in the heart;—in the first case voluntary, in the second involuntary. Touch the pulse of the angry man, if you wish to know whether he really is in anger. When I see a woman weeping or convulsed at any distressing news, and find her pulse in its natural state, I know what to judge of her affliction.—On the contrary, if her grief be concentrated, but her heart beat strongly, or her pulse have been suddenly depressed, I know that she feigns a calm which she does not feel. To judge correctly, we must always compare the external movement with the state of the internal organs. There could be no deceit, were it possible to distinguish the involuntary movements produced in a state of passion, by the action of the heart upon the brain, and then by the reaction of the brain upon the muscles, from the voluntary movements which are occasioned by the simple action of the brain upon the locomotive system.

However strong may be the pain which has been the occasion of the dyspnœa, and impeded circulation, of which we have been speaking, this dyspnœa and distress about the precordia, will cease, provided only that the pain be continued. Nevertheless, if the reaction of the brain were the real cause of the distress in question, the contrary should be the case; for the continuation of the affection of the brain, should continue also to cause its re-action. But here the effect of habit is evident, though the pain subsists; the brain indeed continues to be affected, but the internal organs cease to be so. It may be easily perceived, that I am not here speaking of those cases, where the action of the heart and lungs has been deeply troubled by the effect of pain.