ARTERY, PATHOLOGICAL CONDI TIONS OF.—Notwithstanding the brilliant success that has attended the labours of British surgeons in the department of their profession having reference to the arteries,a success that has deprived haemorrhage of its terrors, and aneurism of hal f its danger, the pathology of the arterial sys tem is still far from being perfectly understood. Doubtless, the appearances of disease in its more advanced and destructive forms have been ac curately described as they have been carefully observed, but that invaluable information which enables a practitioner to detect its early .and silent approach, to trace its progress by con necting each symptom with the morbid change that is going forward, and to predict with accu racy the time and the manner of its termination, is as yet but very imperfect. Many circum stances have unavoidably contributed to this. It is quite possible that arteries may be in an unhealthy condition without presenting any in dication of disease during life, which is, therefore, in the subsequent examination overlooked. It is more than questionable whether arteritis occa sions pain, for it has been observed in situations in which the patient never complained, and as persons do not die from inflammation of the arteries, the intensity of the disease has time to subside, and its effects only remain for obser vation in alterations in the coats of the vessels, or in an aneurism. Many able and intelligent practitioners who have met with aneurisms without number, have yet not seen an example of acute arteritis, and are disposed to consider the red colour of the internal membrane of the vessel observed in cases presumed to be so by others as a staining by the blood after death . These facts prove the imperfection of our know ledge of the pathology of the arterial system ; and years of patient investigation must still be passed both by the bed-side and in the dissecting-room before the dreams of hypo thesis give place to the certainty of scientific demonstration.
In prosecuting this inquiry, that source of information so valuable in the elucidation of other subjects in physiology, the experimenting on animals, is wholly closed ; the artery of the animal bearing no analogy whatever to that of man, either in susceptibility of disease or in the powers of reparation after injury. It appears,
from Dr. Jones's* experiments, that the artery of a dog, if wounded only to a moderate ex tent, is capable of re-uniting and of healing so completely that after a certain time the cicatri zation cannot be discovered, either on its inter nal or external surface; whilst it is nearly certain that in man the wound of an artery can only be healed by the complete obliteration of the vessel at the spot where it has been injured. It is difficult if not impossible to bleed an animal to death by opening a moderately sized artery, whilst few surgeons would be willing to entrust a wound of a branch of the temporal in man to the resources of nature alone. The facts, too, that aneurism is a disease unknown among inferior animals,—that it cannot, by any inge nuity of contrivance, be artificially produced, and that the earthy depositions so commonly met with in the arteries of aged persons are peculiar to the human species, would tend to spew that some difference of structure existed, some pe culiarity favourable to the production of dis ease in the artery of the latter. Indeed, in examining and comparing the artery of a sheep or a dog with that of man, some very obvious differences are apparent : the former is firmer if not actually thicker in its coats ; it maintains its circular form more completely, and seems to possess the quality of elasticity in a greater degree of perfection. These circumstances, however, are insufficient to account for that comparative freedom from disease ; and pro bably the greater susceptibility of man may be traced to the indulgence of certain habits and propensities from which the animal is debarred, and which, in many other instances as well as in this, seem to be the predisposing causes of disease in the human race.