But if the appearance in question implies (as I believe it generally does) a morbid condition, of what kind is that condition? There are the same objections to considering mere redness as equivalent to inflammation here as in the pericardium, or in any other part of the body: here, as elsewhere, in one case it may be the condition out of which inflammation is to spring; while in another it may not be destined to give origin to any change in the structure of the part beyond itself, and may itself constitute the whole disease.
It appears to me, that this mere redness of the internal lining of the heart and arteries has become a matter of undue perplexity to pathologists, because they have laboured to infer from it more than the simple fact itself will authorize. All I wish to establish concerning it is, first, that it is not always (probably very seldom) a mere stain imparted by the colouring matter of the blood after death; secondly, that it alone does not constitute inflammation.
It may not be improper to mention the circumstances under which it has occurred to myself to find it. I have met with it most frequently, and to the largest extent, in subjects whose previous disease has produced a constant and habitual impediment to the transmission of blood through the heart and through the lungs, and that impediment has gone on increasing to the hour of their death; also in those, whatever might have been the nature of their disease, whose dissolution (I mean the actual process of dying) has been tardy and agonizing, and marked by great labour of respiration; in the apoplectic, for example, in whom, after sense and consciousness were extinct, life had been protracted, with stertorous breathing, for many days.
In such subjects the countenance, the lips, and the whole skin, give evidence during life of blood pushed beyond the natural sphere of the circulation, and detained in the extreme blood-vessels. Hence it is obvious that the causes which have loaded and distended the capillaries in every part of the body have had a like influence upon the vasa vasorum.
I do not mean to say that I never met with this peculiar condition of the heart and arteries under other circumstances, or that other causes may not produce it; but that I am not acquainted with it under any other with which, from frequent coincidence, it has seemed to have a natural connexion, or which have afforded a reasonable explanation of the phenomenon.
This condition of the heart and arteries, considered as inflammation, has been assigned by some as the cause of fevers of the more malignant kind. The frequency with which it has been found in some particular epidemic, must have led to the conclusion. But, however this may be, from my own observation, not restricting myself to the fever of any particular season, but taking into account all complaints called febrile, and belonging to all seasons, also from the result of inquiry among medical men who have had large acquaintance with morbid dissections, and from the experience of those who have made this particular point a subject of investigation (Laënnec and Andral) I venture to conclude that it has no essential connexion with fevers of any kind, either as cause or as effect.
On some occasions the internal membrane of the heart and arteries, wherever it exhibits the appearance described, will allow itself to be peeled off from the subjacent structure with the least possible force; this facility of separation ceasing entirely beyond the boundary of the red tinge.
Here unquestionably is further evidence of a diseased condition: but of what nature? Most pathologists would consider this to be of the nature of inflammation—and I believe justly.
There is indeed much difficulty in pronouncing upon the nature of minuter changes of structure detected in the internal parts of the body after death. We are obliged to arrive at conclusions by help of analogies drawn from morbid processes, which we have watched in their progress during life, upon the external surfaces; for during life we have the functions and sensibilities of the part to aid us in forming a right judgment concerning its disease. When, during life, one tissue is separated from another, as the periosteum from the bone, or the cuticle from the skin, or the mutual cohesion between different tissues is sensibly weakened, we find it to be owing to the intervention of serous fluid which does not belong to their healthy state; and this, together with increased vascularity, or redness and heat, and pain, is enough to bespeak the presence of inflammation. All these conditions cannot remain after death. Hence, if we desire to form positive opinions concerning much which is unfolded by dissection, we must supply the defect by analogy. Thus, whenever, in any part of the heart or arteries, the cohesion between the internal membrane and the subjacent structure is manifestly lessened, and the membrane is unusually red at that part, we may regard these appearances as the vestiges of inflammation, without thinking that we go too far in so regarding them.
The internal lining of the heart and arteries is often found red solely in the neighbourhood of ulcerated spaces, when there can be no doubt concerning the existence of inflammatory action.