In so far, therefore, as the extinction of the organic life is concerned, the death by coma, or beginning at the brain, resolves itself into the death by asphyxia, or beginning at the lungs, the difference lying merely in the mode in which the arterialization of the blood is ar rested.
But although this is strictly true as to cases of violent death, produced experimentally in such a way that a single cause only is allowed to operate ; and although we occasionally meet with cases of equal simplicity in disease, and ought always to keep in view the principles which these simple cases illustrate in the treat ment of disease, yet it ought not to be sup posed that either the death by asphyxia, that by coma, or that by syncope, often present themselves to the observation of the medical practitioner in the same simplicity as to the experimental physiologist. We can state from frequent observation, that it is only in a certain number of cases of disease, strictly belonging to the head, such as apoplexy or hydrocephalus, that death takes place exactly in the way of coma, as above described, or that the function of circulation can be observed to survive that of respiration ; and on the other hand there are many instances of disease of the lungs, particularly of phthisis, in which the ultimate extinction of life is rather in the way of syncope than of asphyxia. The simple principle, that
the circulation, though not dependent on any action of the nervous system, is liable to be influenced in various ways by causes acting on the nervous system, enables us to under stand that death may often take place, in the course of diseases, in a way different from that which the seat of the disease may lead us to anticipate.
Nevertheless it may often be of real and practical importance, with the view of ac quiring clear and precise ideas of the modes of fatal termination which are to be expected in the course of diseases, and particularly of such diseases as fever—where the symptoms immediately preceding death, and the causes evidently inducing death, are remarkably various in different individual cases,—to study atten tively the phenomena, and causes, of the fatal termination, in the simpler cases of violent death, such as those which have been here considered.