It is not a little remarkable, says Dr. Carpenter,(*Human Physiology P.505*) that the temperature of the body should frequently rise considerably after death; and this not merely in such cases as cholera, in which it has undergone an extreme depression during the latter part of life; but even in the case of febrile disorders, in which the temperature during life has been above the usual standard. This has been ascertained by Dr. Bennet Dowler of New Orleans, on the bodies of those yellow fever subjects which may be especially referred to as exhibiting a remarking degree of molecular life after somatic death. In one case for example, the highest temperature during life was in the axilla 104 degree; ten minutes after death, it had arisen to 109 degree in the axilla; 15 minutes afterwards was 113 degree in an incision in the thigh; in twenty minutes the liver gave 112 degree; in an hour and forty minutes the heart gave 109 degree and the thigh in the former incision 109 degree; and in three hours after the removal of all the viscera, a new incision in thigh gave 110 degree. It is curious that the maximum heat after death should have been in the thigh, and the minimum in the brain. The post-mortem rise in temperature appears to be essentially due to the passage of the muscles of the body into the state of rigor mortis, a change that is associated with chemical action analogous to that occurring during contraction, and accompanied by a corresponding elevation of temperature. Ackermann has pointed out that the post-mortem rise may in part be due to the persistence of the heat-producing chemical changes in the deeper parts of the body, whilst the radiation and loss of heat from the surface by evaporation is reduced by the contraction of the cutaneous vessels and the cessation of the circulation; and Wunderlich suggests that it may be also in some measure owing to the paralysis of that part of the nervous system which inhibits or regulates the generation of heat, supposing such centre to exist.
The above quotation contains a fair resume of what physiologists have to say in explanation of the post-mortem rise in temperature. You will have observed how vague and unsatisfactory each and all of those explanations are. If the rise in temperature be due to the passage of the muscles of the body into a state of rigor mortis-then how are we to account for the post-mortem rise in temperature of cholera and tetanus subjects? In both of these subjects there have been excessive muscular spasms during life; in tetanus they are accompanied by a rise in temperature of 3 degree to 4 degree, while in cholera the temperature is ordinarily so much low, and often lower still. How is it then that the spasmodic muscular contractions during life could not raise the temperature, while the mere passage of the muscles of the body into a state of rigor mortis is sufficient, shortly before death, or soon after death, and before rigor mortis could actually have set in, to raise the temperature to a considerable height? Why should, moreover, such a rise particularly take place after death from certain disease, seeing that the passage of the muscles of the body into the state of rigor mortis is common to all cases? A similar remark attaches to Ackermann`s suggestion mentioned in the above quotation. In cholera, we are given to understand, the temperature has undergone an extreme depression during the latter part of life, and this is true enough, there having been, owing to causes mentioned before, a reduction in the process of tissue oxidation, and consequently a steady decrease in the production of heat. But this is no reason why such a depression of heat during life must result into an elevation of temperature after death unless it could be shown that one of the immediate effects of death by cholera be an increase of tissue metamorphosis, as a sort of post-mortem vital reaction.
Professor Wunderlich`s suggestion, I am afraid, does not make matters clearer. It is true, there is a good reason to believe that a caloric does exist in all warm-blooded animals which regulates either the production of heat, or its expenditure by means of radiation, conduction and evaporation, or, what is more likely, the balance of caloric production and expenditure. Independently of certain physiological experiments and clinical experiences, which point to the existence of such a heat centre, we have the fact before us, that warm-blooded animals maintain the same body-temperature under extreme varieties of their atmospheric surroundings-a phenomenon which can only be explained by some such regulating agency as suggested although it must be admitted that by virtue of the faculty of adaptation, common to all living beings, even lower animals, void of a nervous system, aye, even plants may be made gradually to endure extremes of temperature. How little Professor Wunderlich`s suggestion helps us to unravel the mystery of post-mortem rise of temperature will, however, be seen from the following considerations. Let us examine the phenomenon under discussion in cases of death from febrile diseases. In all such cases the chief cause of the excessive heat during life is, no doubt, excessive tissue metamorphosis. Now to explain in such cases the additional rise of temperature after death, in the way Professor Wunderlich attempts to do, appears to me to be a sort of explanation which assumes to take for granted the very object of explanation. What we want to know is this: Where does the increase of heat come from after death, since both circulation and respiration have ceased; since consequently, the very hearth of combustion has been extinguished for want of oxygen? In answer to this we are told, that with the cessation of life there is no more any inhibition in the production of heat-an answer which, in order to be satisfactory, must necessarily suppose that neither the impulse towards heat production, nor the materials of combustion have experienced the slightest diminution for some time after the cessation of life. I need not tell you that this is just what we wish to have explained.
As to non-febrile diseases, the inhibitory theory is out of place altogether, for the simple reason, that there is nothing to inhibit, the tendency being towards deficient heat production even during life; we had then again to fall back upon some such hypothesis as a post-mortem vital reaction to account for increased heat production.
As far as I know, I hardly think that pathologists have thrown any more light upon the subject. Dr. Radcliff says: the body has been found to become very hot before death and to remain very hot after death in cholera, in yellow fever and in several other cases in which instances are given by Dr. Erb and by several other writers in Germany, and by Dr. Ringer, Weber, Murchison, Sanderson and many others. The cause of death in the majority of these cases being some sudden affection of the brain, coma in others. And this has been again taken as a clinical proof of the existence of a caloric centre. Paralysis of the brain would then, in certain cases, include the hypothetical centre, which is supposed to be inhibitary in its function. The temperature rises as the time of death approaches, when the state of the circulation must be every moment becoming more and more the reverse of increased activity; the temperature continues to rise even after actual death, when the blood has come to stand still…..It is not easy to connect the increased heat of tetanus with the spasms. A part of the increased heat may be accounted for in this manner, but only a small part. Indeed, the simple fact that in one of the cases which has been instanced, a marked abatement in the severity of the spasms was accompanied by an actual rise in the column of mercury, and that the column continued to rise after death, when all spasm is at an end, is in itself a sufficient proof that it is not in muscular action that the explanation of the increased temperature of tetanus is to be found. Moreover, the fact that the temperature rises in the same way before and after death in cases where neither convulsion nor spasm was amongst the symptoms during life, must lead to the same conclusion……. It seems as if one condition of this change in temperature was the paralyzing of a regulating cerebral influence; and beyond this it is difficult to see further, except it be that this paralysis reaching to the vaso-motor nerves, allows the minute vessels to dilate and receive more blood, and that the increased quantity of blood, even though this blood may be stagnant, may lead to increased molecular changes, of which increased heat is an effect.
No wonder after this, that Professor Taylor(* Principle and Practice of Medical Jurisprudence 1883.*) sums up is considerations on the subject with the following words of half despair: The fact connected with the production of heat in the dead body have not received much attention from physiologists.
