The oxygen consumed with carbonic acid, the nitrogen consumed given off were all found increased as would be the case in a fever of the same temperature. We see then that by the stimulation of a particular region to the inner side of the corpus striatum the thermogenic function of the muscles is abnormally increased simultaneously with the oxidative metabolism, and this without encroaching on the motor tract without exciting the motor function and without any action that could fairly be called vaso-motor coming into play. Here we have then an example of excess of thermogenesis solely owing to excess of metamorphosis, without any excess of muscular action coming into play. On the other hand the experiments of Landois, etc., as mentioned before show that stimulation of certain portions of the brain is followed by cooling, and this is attributed by Dr. Ferrier to contraction of the blood-vessels and the heat following lesion of those regions to dilatation.(*Functions of the Brain 1886 pp.87 and 253.*)
Curare abolishes the function of the peripheral nerve- endings and thus blocks the way for the transmission of impulses from the nerve trunk to the muscle. The vaso-motor is intact, but the animal can no longer maintain its temperature, it loses its regulating capacity and gets cold in a cold surrounding, warm in a warm surrounding.
Dr. Macalister (Lancet, March 19, 1887, p.558) has shown by experiments that the thermo-dynamic theory is not so simple as it appears. That, moreover, the function of thermogenesis and muscular contraction are co-ordinate as a rule, but are by no means one and the same phenomenon, that contraction may be continued on stimulation after the heat production capacity had been exhausted. There would then be contraction without rise of temperature.
Having then shown you, gentlemen, that there are caloric centres, and that they do exert their inhibitory capacities in the case of a cholera patient, we are no win a position to understand far better Wunderlich’s suggestion to the effect, that the extraordinary rise in temperature of cholera patients immediately before, or soon after death is due to a paralysis of those centres. We have come to learn that the economy with which choleraic spasms are carried on is altogether exceptional; that a considerable amount of extraordinary energy has to be spent on the part of the caloric centres in order to effect the inhibitory regulation spoken of; and this energy must, according to the law of Conservation of Energy, become converted, in the measure as the centres come paralyzed into heat.
In how far the state of the nerve centres is concerned in the post-mortem rise of temperature, may best be seen from the following observations of Professor Taylor. Cases, he says, where the post-mortem temperature has particularly risen are; injuries to nerve centres, especially the brain or the spinal column; in cerebro-spinal meningitis the temperature has arisen after death from 104 degree to 111 degree F., and in fatal cases of small-pox attend with much delirium, Simon observed that the temperature rose at death from 104 degree to 113 degree F.
It appears then that these observations confirm in the main the views I have tried to establish. As explained before, the post-mortem rise of temperature in general is supposed to be due to a gradual transformation of potential energy in the form of molecular work, into energy in the form of heat. Suppose then that this transformation, instead of being gradual, as is ordinary the case, would, under some extraordinary circumstances be sudden, what effect would this have upon the evolution of heat? Why, there would be a sudden and considerable rise of temperature. Now this is just what happens when death occurs on consequence of injuries inflicted upon the nerve trunks or upon the brain. The molecular work by which the nervous and cerebral irritability had been sustained, has suddenly been suspended; the potential energy dwelling in those organs, can no more give rise to constructive molecular work, to automatic action or to unconscious cerebration; and so it comes that this very potential energy is suddenly set free and explodes in the form of an extraordinary amount of heat. There is a sudden rise of high temperature.
Again, when there is during life-time an extra-ordinary amount of nervous or cerebral irritation, even gradual extinction of those latent activities must necessarily give rise to an evolution of an amount of heat far higher in degree, than would have been the case, had there been a normal state of irritability at the approach of death. In cerebro-spinal meningitis, and most likely in yellow fever too, there is an extraordinary amount of nervous and cerebral irritability manifested during the course of the disease, and the consequence is, as we have seen, an extraordinary post-mortem rise in temperature.
Ordinarily post-mortem heat, that is to say the continuance of a certain amount of heat evolution after death, without being marked by any extraordinary rise, has been explained on the supposition that molecular life continues to a certain extent after somatic death has taken place. There is certainly a good deal of truth in this, known as it is, that tissue irritability subsists for some time after death. What I believe however to be just as true, and what I wish therefore to impress on your mind is this, that the post-mortem heat is not only owing to a temporary subsistence of molecular life, but in no less a measure, and perhaps to a far greater measure to the setting in of molecular death.
I wish further to draw your attention to the fact that the spasms of the extremities, occurring in cholera, far from being an additional evil,. causing pain, exhaustion, &c. are in reality accessory to the chief evil of the disease, which is, as we have already heard before, venosity of the blood. For however economically the muscular work of morbid contraction may be carried on within the organism, the fact remains that there is an unnecessary not to say a mischievous-piece of work thrust upon the voluntary muscles, too entertain which a certain amount of additional combustion and consequent disengagement of carbonic acid is required. Thus a cholera patient might be said to move in a vicious circle: Owing to a state of venosity of the blood, the muscles of his extremities gradually begin spasmodically to contract; and owing to the spasmodic contraction of the muscles, additional carbonic acid gas is generated which renders the blood so much the more venous, as respiration is difficult and the exhalation of the noxious gas by the lungs is consequently retarded. Remember at the same time that the very dyspnoea spoken of, is again due to spasmodic contraction of the pulmonary arteries- and the vicious circle mentioned before, will be found to be, if possible, more than complete.
Again, if it be true, as I believe I have satisfactorily shown, that the spasmodic contraction of the pulmonary arteries gives rise, under the specific influence of the cholera poison, to a serous transudation, in the alimentary canal, and that serous transudation, on the other had, by depriving the blood of its watery parts, gives rise to motor nerve irritation and consequent spasmodic action of muscular tissue in general, and of the muscular tissue of the pulmonary arteries in particular- then we have here before us another vicious circle within which cholera patient unavoidably moves. Then we have further the fact before us, mentioned at the end of the previous lecture, that the sudden withdrawal of fluids from the body, disturbs the pressure under which both the nerves and muscles are, and secondarily disturbs the equilibrium of action. Finally deficiency of nutrition as is invariably the case in cholera is in itself a source of irritation and gives rise to that restlessness so consuming just at a time when husbanding of strength is of utmost importance. No wonder therefore that the disease of which you heard so much in the course o these two lectures often makes such rapid progress.
In a country like India, where the people at large have yet to learn the value of time, the above considerations can not be too emphatically impressed upon the mind of those whom it my concern. Cholera in some epidemics, and in some individuals in every epidemic has the peculiarity of making its first appearance between midnight and three to five o’clock in the morning. Patient would suddenly be roused by a urgency to go to stool; the first evacuation may be more or less natural, or partake of the nature of the diarrhoeic stool he was accustomed to, sine a few days; but soon matters change, and the disease assumes its true character. Now in such cases there should be no waiting for medical aid till day break. Time is life! and this is no where more true than in all matters concerning cholera.
I have had much to say in the course of this lecture about the state of the nervous system-vaso-motor and motor- and the nerve-centres. There is hardly anything to be said about the state of the brain. There are no characteristic organic changes to be found in the cerebral substance after the death of cholera subjects; and if there is anything remarkable with regard to the start of their mind during life-time, it is the frequent retention of full consciousness to the last, accompanied in many cases by a calmness which strangely contrasts with the real danger of the situation, of which the patient can hardly be unaware.
