Part 4

At the period in which this physician wrote, the vital forces had not been analyzed. It was necessary to employ physical forces to explain vital phenomena; hence it is not astonishing that all his theories are so incoherent. In fact, theories in the vital phenomena borrowed from physical forces, exhibit the same inadequacy, as those would in the physical phenomena borrowed from vital laws. What would you say, if in explaining the motion of the planets, rivers, &c. they should talk of irritability and sensibility? you would think it absurd; it is equally absurd, in explaining the animal functions, to talk of gravity, impulse, inequality of the capacity of the tubes, &c.

Observe, that the physical sciences made no progress until they analyzed the simple laws that preside over their innumerable phenomena. Observe also, that medical and physiological science was not accurately explained, until the vital laws were analyzed, and it was shown that they were everywhere the principles of the phenomena. See with what ease all those of the secretions, exhalations, absorptions, inflammation, capillary circulation, &c. are referred to the same principles, flow from the same data, by deriving them all from their real cause, the different modifications of the sensibility of the organs which execute them. On the contrary, see how each presented a new difficulty, when the mechanical causes were employed to explain them.

From what has been said, it is then evident, that in the innumerable variations of which the fluids of the capillary system are susceptible, in the different portions of the system which they fill, there is always antecedent variations in the sensibility of the vascular parietes; these varieties produce the first.

It is especially in the capillary system and its circulation, that the variations of the organic sensibility of the vessels produce varieties in the course of the fluids; for as I have observed, in the great arterial and venous trunks, in the heart, &c. the fluids are in too large masses, and they are agitated by too strong a motion, to be thus immediately subjected to the influence of the vascular parietes. Thus when nature wishes to prevent the fluids from communicating in the trunks, it places among them valves, or other analogous obstacles, which become useless in the capillary system.

Though the anatomical arrangement be the same in the living and the dead body, there is then a very great difference in the course through the capillary system, in one and the other. Push, into the aorta of an animal in whom you destroy life by opening this artery to fix in it a syringe, different fine fluids; you will never see them fill the capillary system, pour out by the exhalants, the excretories, &c. as when the subject has been some hours deprived of life. The organic sensibility inherent in the parts repels the injection; it can only circulate in the great trunks, in which there is a large space. I have injected, with other views, a great number of times, fluids by the arteries and the veins; now, the capillary system is never filled with these fluids; they circulate only in the great vessels, when the animal can bear them. Mr. Buniva has also made comparative experiments with injections upon living animals and those deprived of life; he has experienced in the first a resistance which he has not found in the other; now this resistance is in the capillary system, whose vessels refuse to admit a fluid to which their organic sensibility is not accommodated.

VI. Consequences of the preceding principles, in relation to Inflammation.

From what has been said thus far, it is easy, I think, to understand what takes place in the inflammatory phenomena, considered in general.

If a part be irritated in any manner, immediately its organic sensibility is altered, and increased. Without previous connexion with the blood, the capillary system is then placed in relation with it; it as it were calls it there; it flows there and remains accumulated until the organic sensibility returns to its natural type.

The entrance of the blood into the capillary system is then a secondary effect of inflammation. The principal phenomenon, that which is the cause of all the others, is the local irritation which has changed the organic sensibility; now this local irritation may be produced in different ways; 1st, by an irritant immediately applied, as a straw upon the conjunctiva, cantharides upon the skin, acrid vapours upon the mucous surface of the bronchia or the nasal cavities, atmospheric air upon any internal organ laid bare, as we see in wounds, &c.; 2d, by continuity of organs, as when a part of the skin, of the pleura, &c. being inflamed, those that are near it are also affected, and the blood flows there, as when one organ is diseased, that which is near it becomes so by the cellular communications; 3d, by sympathies; thus the skin being seized with cold, the pleura is sympathetically affected; its organic sensibility is increased, the blood immediately enters it from every part. When this property is raised in one of these three ways in the capillary system, the phenomena that result from it are the same. For example, when in the pleura it is raised because the air is in contact with this membrane, because the lungs that it covers have been first affected, or because coin has seized upon the skin in sweat, the effect is nearly analogous, as it respects the entrance of the blood in the capillary system.

It is then the change that takes place in the organic sensibility, that constitutes the essence and the principle of the disease; it is this change which makes a pain more or less severe soon felt in the part; then the sensibility that was organic, becomes animal. The part was before sensible to the impression of the blood, but did not transmit this impression to the brain; then it transmits it, and this impression becomes painful. Irritate the healthy pleura in a living animal; it does not suffer; irritate it on the contrary during inflammation, and it gives signs of the most acute pain. Who does not know that most often and almost always, a pain more or less acute is perceived in the part, some time before it becomes red? Now this pain is the indication of the alteration that the organic sensibility undergoes; this alteration exists some time, often without producing an effect; this effect, which is especially the afflux of blood, is subsequent.

It is the same of heat. I shall say hereafter how it is produced. It is sufficient now to show that it is, like the passage of the blood in the capillary system, only an effect of the change that has taken place in the organic sensibility of the part; now this is evident, since it is always consequent upon this change.

There happens then in inflammation exactly the reverse of what Boerhaave thought. The blood accumulated according to him, in the capillary vessels, and pushed à tergo by the heart, as he termed it, was truly the immediate cause of the affection, whereas, from what I have said, it is only the effect.

If we reflect a little upon the innumerable varieties of the causes which can alter the organic sensibility of the capillary system, it will be easy to understand of what infinite varieties inflammation is susceptible, from the momentary blush that comes and goes in the cheeks, to the most serious phlegmon and erysipelas. We might make a scale of the degrees of inflammation. By taking the cutaneous, for example, we should see at the bottom the redness that arises and disappears suddenly by the least external excitement upon the dermoid system, which we can produce at will, and in which there is only an afflux of blood; then those that are a little more intense, which occasion cutaneous efflorescences of some hours, but without fever; then those that continue for a day, with which there is some fever; then erysipelas of the first order; then that which is more intense, and which gangrene soon terminates. All these different degrees do not suppose a different nature in the disease; the principle of them is always the same; there is always, 1st, an antecedent increase of organic sensibility, or alteration of this property; 2d, afflux of the blood only if the increase is not great, afflux of the blood, heat, pulsation, &c. if it is. As to fever, it is a phenomenon common to every severe, acute local affection; it appears to depend on the singular relation which connects the heart with all parts; it has nothing peculiar in inflammation, but the particular modification it receives from it.

The afflux of the blood in an irritated part takes place in inflammation, as in an incision. In this the divided point has been irritated by the instrument; soon the whole blood in the neighbourhood flows there and escapes by the wound. This afflux is so evident a result of irritation, that in a slight incision, the blood scarcely flows at the instant of the division of the integuments, because there is but little of this fluid at the divided place; but a moment after, the irritation which has been felt, produces its effect, and it flows in a quantity disproportioned to the incision.

When the alteration of the organic sensibility which produces inflammation, has no varieties except in its intensity, the inflammation itself differs only in degree. But the nature of the alteration is oftentimes different; a feeble character is frequently united with it; the part has then less redness, heat, &c. Other modifications are also observed; now all these depend upon the difference of the alterations that the organic sensibility experiences; at least these alterations always precede them.

The influence of these alterations is not less evident when inflammation terminates, than when it begins. If the organic sensibility has been so raised, that it is as it were exhausted, then the solid dies, and the fluid, which is no longer in a living organ, soon becomes putrid. Examine the phenomena of every gangrene; putrefaction is certainly only a consequence; there is always, 1st, a desertion of the solids by the vital forces; 2d, putrefaction of the fluids. The first is never a consequence of the second. When the organic sensibility begins to diminish, the blood brought there by inflammation is already susceptible of putrefaction; but the defect of tone in the solid always precedes. There is this local phenomenon, as well as the general, in putrid fever. It is incontestable that in this fever, the blood has a tendency to be decomposed, to become putrid; I will say further, that it often exhibits a commencing putrefaction. The index of the alteration of this fluid is always the general state of the forces of the solids; these have first lost their spring; the symptoms of weakness are evident before those of putridity. All the animal fluids tend naturally to putrefaction, which takes place inevitably when life abandons the solids in which they circulate. In proportion as the forces diminish in the solids, this tendency is manifested. A commencement of putrefaction in the fluids during life, is not a general phenomenon more improbable than the local phenomenon of which we have spoken, viz. that the blood of an inflamed part begins to putrefy and the part consequently becomes fetid, before the organic sensibility has entirely abandoned the solid. It is only when this ceases, that this putrefaction becomes complete; but then it is extremely rapid, because it had commenced during life. So bodies that have died of putrid fevers decompose with a rapidity far surpassing those that have died of other diseases, because putrefaction had really commenced before death.

Inflammation with a livid colour, small degree of heat, prostration of the forces in the part, and termination by gangrene, is evidently to well marked adynamic fever, what phlegmon is to inflammatory fever, what irritation of the primæ viæ, which is called bilious affection, is to the meningo-gastric fever, &c. I think if we examine attentively local affections and general fevers, we shall always find a particular kind of fever corresponding in its nature to a particular kind of local affection. But let us return to inflammation.

If it terminates by suppuration, it is evident that there is a new alteration of the organic sensibility to produce pus. The same thing in scirrhus. The termination by resolution takes place when this sensibility returns to its natural type. Examine well the inflammatory phenomena in their succession; you will see, that always a particular state in this property, precedes the changes they exhibit.

When our medicaments are applied upon an inflamed part, it is not upon the blood that they act; it is not by lessening the heat, or relaxing. The expressions to soften, unbend and relax the solids, are inaccurate, because they are borrowed from physical phenomena. We relax, we soften dry leather by moistening it; but we only act upon the living organs, by modifying their vital properties. Observe that though we already begin to recognize the empire of these properties in diseases, medical language is still wholly borrowed from theories which employ physical principles in the explanation of morbid phenomena. We have arrived at a period when the manner of expressing ourselves upon these phenomena should be changed; I do not here speak of the names of diseases. Certainly every emollient, astringent, discutient, relaxing, tonic, medicament, &c. employed with different views upon an inflamed part, only acts by modifying differently from what it was, organic sensibility. It is thus that our medicaments cure or often aggravate diseases.

From what has been said, it is evident that the solids perform the first part in inflammations, and the fluids only the second. Modern authors have perceived this truth, and they have immediately assigned an important part, in this respect, to the nerves; but we have seen that these appear foreign to organic sensibility, that they are so even after the most rigorous observation. The nervous influence, that at least which we know in other parts, is, in inflammation, as in secretion, exhalation and nutrition, almost entirely wanting. There is in this affection, unalteration of the organic sensibility, and this is every thing.

The kind of blood varies in inflammation, and in this respect, I think the following rule is generally uniform; whenever the organic sensibility is much raised, the life augmented and there is an increase of forces in the inflamed part, then it is the red blood that remains in the capillary system; then there is always great heat there. On the contrary, when the inflammation approaches the putrid character, the part becomes of a dull and livid colour; the capillaries appear to be filled with black blood; the heat is less. In general, a bright colour, in all eruptions analogous to inflammatory tumours, announces the increase of the organic sensibility. A livid colour, on the other hand, indicates its prostration; petechiæ are livid; scorbutic blotches are so; a livid colour in tumours is the forerunner of gangrene. Do you wish to know when cold acts as a stimulant? It is when it reddens the end of the nose, the ears, &c. When these parts become livid, other phenomena announce at the same time, that its action is sedative. This is supported by my experiments upon life and death, which have proved that the black blood everywhere interrupts the functions, weakens, annihilates even the motion of the parts, when it is brought to them by the arteries.

Differences of Inflammation, according to the different Systems.

From what has been said upon inflammation, it appears that it has for its seat the capillary system, for its principle an alteration in the organic sensibility of this system, for its effect the afflux of blood into vessels in which it did not before circulate, a consequent increase of caloric, &c. Now where the capillary system is more developed, where the organic sensibility is greater, inflammation ought to be more frequent; and this is the case. It is especially in the cellular, serous, mucous and dermoid systems that we observe it; fine injections demonstrate in these systems a capillary net-work infinitely superior to that of the others. Besides, as if there is not only nutrition, but also exhalation and oftentimes secretion in these systems, there must be more organic sensibility, a property from which all these functions are derived.

On the contrary, inflammation is rare in the muscular, osseous, cartilaginous, fibrous, arterial, venous systems, &c. where there are but few capillaries, and where the organic sensibility presiding only over nutrition, is necessarily found in a less degree.

Besides, as the capillaries make an integral part of the system where they are found, and as each system has its peculiar kind of organic sensibility, it is evident that they ought to partake of this kind; now as it is upon this property that all the inflammatory phenomena depend, they ought to present an aspect wholly different in each system. This is what we shall be convinced is the case by an examination of each. I shall only present here generally, that essential point of view, upon which authors have not insisted.

Let us take first the systems most exposed to inflammation; we shall see that phlegmon is the inflammatory kind of the cellular, erysipelas that of the dermoid, and catarrh that of the mucous. We have not yet a general name to express that of the serous; but who does not know how it differs from the others?

In the systems rarely subject to inflammation, we know this affection infinitely less than in the preceding; but there is no doubt that it differs essentially. Compare the length and permanency of that of the bones, with the rapidity and disposition to change of that of the muscles, or rather of the fibrous bodies, in rheumatism.

The results of inflammation do not vary less than its nature; if resolution does not take place, each has its own mode of suppuration. Compare the pus of erysipelas, that of phlegmon, the milky or flocculent fluid of the serous membranes, the whitish or greyish humour, of a mucous consistence, that escapes from the membranes of the same name after catarrh, the blackish sanies of the bones in suppuration, &c. We shall see that some organs, as the fibrous bodies, do not suppurate.