General Anatomy, Applied to Physiology and Medicine, Vol. 2 (of 3)

by Xavier Bichat

What disposes the mucous exhalants more than all the others to pour out blood? It appears to be because the capillary system whence they arise is constantly entered by blood, and the course is very short from this fluid when present in the capillaries to the mucous surfaces. This is so true, that those portions of the mucous system that have but little of this fluid in a natural state, as those of the sinuses of the face, of the ear, &c. are less subject to hemorrhages. I am confident, that if there were exhalants upon the muscles to pour out constantly a fluid upon the exterior of these organs, hemorrhages would be very frequent in them.

Hence we see that the mucous hemorrhages have nothing in common, but the extravasation of blood, with those which are the effect of hemorrhoids, and always suppose a rupture of the veins, with those that aneurisms or varices produce, with those that are the effect of a cut, of a violent concussion, &c. They form a class by themselves, and resemble those only that the exhalants furnish upon the other surfaces where they open.

If I should class hemorrhages, I should distinguish them, 1st, into those that come from exhalation; 2d, into those that are produced by rupture. I should place among the first the bloody sweats, the mucous, serous, cellular hemorrhages, &c.; among the second, those that accompany wounds, aneurisms, &c. In order to embrace in one view all the sanguineous evacuations that can happen in the animal economy, I think it absolutely necessary to adopt this division which moreover accords with the phenomena and treatment of hemorrhages. Would you bleed to arrest a hemorrhage from rupture? undoubtedly not; but you would bleed to check an active hemorrhage by exhalation, because by diminishing the mass of blood, you diminish the excess of organic sensibility which produces the hemorrhage; it is nearly the same as when we bleed for inflammation. It is certainly necessary that the hemorrhage should be stopped as it has been produced; it is necessary that the sensibility of the exhalants should return to its natural type before the blood ceases to flow. We do not bleed to draw the blood to another place, as has been said; if it was so it should be done in passive hemorrhages. Most of those who bleed much in hemorrhages, believe that plethora is the sole cause that produces them, that the vessels containing too much blood, require a part of it to be taken away; but there are many more cases of active hemorrhage in which there are no signs of plethora, than there are of those in which these signs exist. There may be a real deficiency of this fluid in the great vessels, but if the exhalants of a part are by their peculiar sensibility in relation with it, they will pour it out in as great abundance as if there was an excess of it. It is as in the increase of natural secretions, exhalations, &c. Whether there was plethora or not in the great vessels, when the local affection has raised the peculiar sensibility of the secretories or the exhalants, they would draw abundantly from the blood. The influence of plethora upon the increase of the different fluids which are separated from the blood, is evidently one of the remains of the opinions of Boerhaave. If the heart agitated everywhere the fluids, if it propelled the blood, the serum, &c. that go out by the exhalants, the, secreted fluids that go out by their ducts, this influence would necessarily be real; but since all the fluids going from the capillary system are necessarily beyond every action of the heart, as in their circulation, they are wholly under that of the organic sensibility and tone of the capillaries, it is evident that these fluids are independent of the quantity of blood contained in the great vessels and moved by the heart; that the alterations of the vital forces of the part are the sole causes of the different phenomena that their course exhibits.

Who does not know that feeble and delicate temperaments are often subject in women to a much more copious menstruation than those that are stronger, more vigorous, more sanguineous, as it is called? You will find many results in authors, upon the quantity of blood evacuated by the catamenia, and you will observe at the same time that these results do not resemble each other; why? because each womb has, if you may so say, its own temperament, which oftentimes does not correspond with the general temperament, because each is disposed consequently to a different kind of vitality. There is more or less blood then given at each menstruation, as it is given for a greater or less time, for some women have at first only a serous fluid, while others have blood immediately. I cannot repeat it too much, that every vital phenomenon is necessarily subjected to many irregularities, which arise from those to which the vital forces are themselves exposed. On the contrary, every physical phenomenon is almost immutable, because it is the nature of physical laws to remain always the same.

Hence we see how hemorrhages of the great arteries, which are under the immediate influence of the heart, should differ essentially from those of the capillary system and of the exhalants, whose phenomena are under the influence of the forces of the part where they happen, whether they arise from rupture or exhalation. Though in fact these two classes may be essentially different in their principal phenomena, as I have already said, yet they approximate, because the modifications of the vital forces of the part have a necessary influence upon them when they are in the capillary system. Thus astringents, tonics, styptics and other medicines which evidently act upon the organic sensibility and the insensible contractility, frequently stop hemorrhages of the capillary system. The contact of the air, by modifying these properties in wounds is even sufficient to produce this effect. On the contrary, ligatures alone can, in the great vessels, resist the powerful influence of the heart. All styptics imaginable may be heaped upon an open artery, and they would not check the effect of this influence. This then is the essential difference between the hemorrhages of the capillaries and exhalants, and those of the arteries, that every medicine which acts upon the organic sensibility and tone, can be advantageously employed for the first, whereas they have no effect upon the second. I go now to the sanguineous exhalations which are made by the recrementitious exhalants.

Hemorrhages of the Recrementitious Exhalants.

The serous membranes are the frequent seat of hemorrhages. The examination of dead bodies incontestably proves it. Nothing is more common than to find in the peritoneum, the pleura, the pericardium, &c. a serum, reddish if a little blood is effused, very red if more, and even pure blood is found under certain circumstances.

I have made these observations in two different cases, 1st. After inflammations whether acute or chronic, especially the last. The serous sac then contains a greater or less quantity of blood, sometimes alone, more frequently mixed with serum, and now and then even with whitish and albuminous flakes. The previous inflammation seems to rank these hemorrhages among the active. 2d. Often at the end of organic diseases, in which the exhalations of serum increase almost uniformly in the serous sacs so as to produce dropsies evidently passive, a greater or less quantity of blood is mixed with this serum. What anatomist has not observed these bloody effusions in the pericardium, the pleura, &c.? I have observed that the tunica vaginalis and arachnoides are infinitely less subject to them than other similar sacs; I have never seen them in the last, and twice only in the first. I of course do not speak of the hemorrhages that are the effects of wounds of the head and in which the blood is effused between the two folds of the arachnoides.

I have carefully examined the internal surface of the peritoneum, the pleura, and the pericardium, after this kind of hemorrhages, produced either in consequence of the inflammation of the membrane itself, or of an organic disease; their surface has appeared to me to be perfectly sound, so that it is very evident that the exhalants have furnished blood, instead of the serum they threw out there before.

I compare a serous surface preternaturally pouring out blood after inflammation, with the active hemorrhages of the mucous surfaces. On the other hand, when the serous exhalants throw out blood at the end of organic diseases of the heart, the womb, the lungs, &c. it is certainly the same phenomenon, as when blood brought by the mucous exhalants, under like circumstances, is thrown off by spitting, vomiting, or stool.