General Anatomy, Applied to Physiology and Medicine, Vol. 1 (of 3)

by Xavier Bichat

From what has been said, it is evident that all the phenomena, over which preside what are commonly called the tonic forces, viz. organic sensibility and insensible contractility, are completely independent of nervous action; and consequently that these properties would not, like those of animal life, require this action. Each kind of sensibility has its morbid phenomena over which it presides. Inflammations, suppurations, the formation of tumours, dropsies, sweating, hemorrhages, disorders of secretions, &c. &c. belong to the alterations of the organic sensibility, whilst every thing like spasm, convulsion, paralysis, trance, torpor, injury of the intellectual functions, &c. &c. every thing, in fact, which tends in diseases to destroy our relations with surrounding bodies, belongs to the alterations of animal sensibility or contractility, and implies a greater or less degree of disorder in the nervous system.

In general, the diseases that affect the functions of animal life are of a nature wholly different from those which destroy the harmony of organic life. They have not the same character, the same progress, and the same phenomena. Place on one side the injuries of the external senses, blindness, deafness, loss of taste, &c.; those of the internal senses, mania, epilepsy, apoplexy, catalepsy, &c.; those of the voluntary motions, &c.; on the other, fevers, hemorrhages, catarrhs, &c. and all the diseases that disturb digestion, circulation, respiration, secretion, exhalation, absorption, nutrition, &c.; we shall then see what an immense difference there is between them.

Physicians have used too vaguely the term nervous influence. If in medicine, as in physiology, we had accustomed ourselves to use those expressions only to which was attached a precise and definite meaning, this would have been employed much less frequently.

It appears that the nerves have some influence still unknown, in the production of animal heat. The following facts relate to this influence. 1st. In aneurism, the ligature of the nerve is often followed by a sensation of general torpor and coldness in the limb. 2d. Sometimes, in hemiplegia, the affected part is of a temperature below what is natural, though the pulse may be as strong in this side as the other. 3d. One of the characters of ataxic fevers, the principal seat of which is in the brain, is the remarkable irregularity in the temperature of the different parts of the body. 4th. Animals, with a strongly marked nervous system, as quadrupeds and birds, are those of all others, in whom the degree of natural heat is the highest. 5th. I knew a person that had had the cubital nerve divided by a piece of glass above the pisiform bone, and whose little and ring fingers of that hand uniformly remained colder than the rest. 6th. Often in luxations, the compression of the nerves by the heads of the bones, produces an analogous effect, &c. &c.

However, the heat is not always increased, when the nervous action is augmented, nor is it always lessened when this action diminishes; there are as many cases in which the heat appears to be independent of the nervous system, as there are where it appears to be connected with it; so that we are still confined here to the collection of facts, without drawing general conclusions from them.

Sympathies.

I divide what I have to say upon the sympathies of the nerves, as I did that which was said upon their vital forces; that is to say, I shall examine first the relations that each nerve has with the other parts, then I shall speak of the general influence that the nervous system exercises upon the sympathies and of the part it takes in them.

Sympathies peculiar to the nerves.

There is no doubt as to the relations of the nervous with the other systems, of those which it has with the muscles and with the brain. In fact, these relations are natural; for the one cannot be affected without the other's feeling it. These three organs can in this respect be considered under one point of view. Thus too, the pulsation of the arteries is always connected with the action of the heart, &c. Every idea of sympathy excludes that of a natural connexion of functions. Barthez is mistaken upon this point. I speak only of the unnatural relations of the phenomena that take place between an organ and a portion of the nervous system which is not connected with it by the natural order of life; now, thus considered, the nervous sympathies are very numerous.

1st. Two nerves of the same pair often sympathize with each other. We know in medicine the relation there is between the two optic nerves; the one being disordered in its functions, the other frequently becomes so. This happens more rarely with regard to the ears, the nostrils, &c. though it sometimes takes place in them. Often in neuralgia (a word which I adopt very willingly and which is wanted in the science to express a class of diseases every genus of which has a distinct name) often I say in neuralgia a nerve being painful, the corresponding one becomes so sympathetically. I have an example of this at present; it is a woman, who for two months has been afflicted with sciatica of the left limb. In changes of weather, a pain precisely similar spreads itself along the course of the nerve of the opposite side. I applied two blisters upon the thigh first affected; the pain disappeared in both sides at the same time at the end of twelve hours. Thus, in order to cure pains in both eyes, it is oftentimes sufficient to act only upon one, &c.