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.
Gangrene once taken place, is everywhere the same, since it is only the absence of life, and all dead organs have the same properties. But according to the sum of organic sensibility which each system has, it is more or less disposed to die after inflammation, in the midst of others which retain their life. Who does not know that the carbuncle which soon kills the part it seizes, only attacks certain systems; that the osseous, the cartilaginous, the nervous, &c. are always exempt from it?
The essential fault of every medical doctrine is that of considering diseases too abstractedly; they are so modified in each system, that their aspect is wholly different. If I may be allowed the expression, it is always the same individual, but in entering each system, it has a different appearance there, so that often you cannot recognize it. When will medicine be so far advanced that the treatment will correspond with these varieties? There should certainly be a general treatment of inflammation; but it should be modified differently, according as we apply it to phlegmon, erysipelas, catarrh, &c.
This then is a very evident proof of that peculiar character which inflammation takes in each part. We know with what ease and rapidity the blood flows to any part of the skin in consequence of irritation there; prick or rub briskly a part of this organ, it reddens in a moment. This takes place also, though less sensibly, on the mucous surfaces. This is not equally seen upon the serous; I have frequently ascertained this on living animals, when I have laid bare these surfaces and irritated them in different ways. The afflux of the blood does not immediately follow the irritation: there is always an interval between one and the other, never less than an hour.
VII. Structure, and Properties of the Capillaries.
What is the structure of the capillaries? So great is their tenuity that we evidently cannot have upon this point, any kind of data founded upon experiment and observation. Only it is very probable, it is even certain, that this structure is modified differently in each organ, that it is not the same in the tendons, the aponeuroses, the muscles, &c. that it really partakes of the nature of the organ of which it makes an integral part.
The membrane which lines the excretories, the arteries, the veins, the exhalants, vessels which go into the system of the capillaries or come out of it, is very like that of these capillaries; but it is not certainly the same.