This extreme motor relaxation, which in my observation is rare, seems to have been very common in the epidemic described by Barclay,4 as he states that in a large proportion of the cases, from the commencement of the attack until its termination in death, the patient never moved a limb or even an eyelid. Petechiæ and ecchymoses, the evidences of broken-down blood, were present in some of my cases, and there was in one or two instances a fetid hemorrhagic exudation from the nostrils during life. A symptom which has almost escaped the attention of authors was a peculiar odor, which was most marked in patients who had involuntary passages, but was very distinct from any fecal odor. The stools emitted it very strongly, but so did the skin and breath. It was so distinctive as to render possible the recognition of a case by the sense of smell alone. The discharges from the bowels were liquid and very often involuntary. None of my cases passed urine whilst under observation.
4 Madras Quarterly Journal, 1860, 364.
It is plain that the symptoms of coup de soleil, as usually seen, may be summed up as those of intense fever, accompanied by profound nervous disturbance (as manifested by insensibility with or without delirium, and by motor symptoms, such as convulsions or paralysis), by arrest of glandular action, and by changes in the blood. In this ordinary form of sunstroke death takes place by asphyxia or by a slow consentaneous failure of both respiration and cardiac action. It very rarely occurs in less than half an hour after the first decided symptoms, and usually is postponed for a much longer period.
There is a form of coup de soleil in which death results almost at once, and probably always by cardiac arrest, and to which the name of the cardiac variety may well be given. It is very rarely, if ever, met with in civil life, and among soldiers is especially seen during battle or at other times when great exertion is being made. These cases will be more fully discussed in a later portion of this article.
POST-MORTEM CHANGES.—Owing to the excessive heat of the body, putrefactive changes occur very rapidly after death from sunstroke, and various described lesions, especially of the heart, have been undoubtedly the result of post-mortem changes. Later observers have confirmed my original observation, that if the body be opened directly after death the left ventricle will be found firmly contracted, though the right heart and the pulmonary arteries, with their branches, are gorged with dark fluid blood. In my cases the lungs did not present at all the appearance of congestion of their minute capillaries, but when they were cut the blood poured from them abundantly, seemingly from their larger vessels. Not only do the lungs suffer from venous congestion, but the whole body also. The blood appears to leave, as it were, the arterial system and collect in the venous trunks. The arterial coats are often stained red, apparently by the broken-down red corpuscles of the blood.
There can be no doubt that the blood suffers in sunstroke very similarly to what it does in low fevers. Its coagulability is impaired, but not always destroyed; and it is possible that in the very rapid cases it may not be decidedly affected. After death it appears as a dark, often thin, sometimes grumous fluid, whose reaction is very feebly alkaline, or, as I have seen it, even decidedly acid. Levick5 appears to assert that the blood-discs, as seen by him under the microscope, were shrivelled and crenated, and showed very slight tendency to adhere in rouleaux. In several of my cases the blood was carefully examined by the microscope, but nothing abnormal was found. The extravasations of blood which have been found by K. Köster in various parts of the nervous system are probably of the nature of petechiæ, the results of the altered blood-crasis, and not due to any especial affection of the nerve-centres.
5 Pennsylvania Hospital Reports, 1868, 373.
THEORY OF THE DISEASE.—The theories which have been brought forward as explanatory of the phenomena of sunstroke are so various that it would be impossible in the limits of this paper to discuss them. It does seem, however, proper to give a very brief historical sketch of the development of our present knowledge of the subject. In 1854, H. S. Swift6 said that the disease is “now generally admitted to be merely exhaustion produced by fatigue,” although he recognized the existence of an “apoplexy produced by insolation.” The cases which Swift so well describes as those of heat-exhaustion were true instances of thermic fever. The physicians of the Pennsylvania Hospital, especially Gerhard, early called attention to the resemblance of sunstroke to a fever, but it was not until January, 1859, that their views found expression in print in the paper published by James J. Levick in the American Journal of Medicine. This observer tabulated the post-mortem appearances of typhus fever and of sunstroke in contrast, calling attention also to the similarity of symptoms during life. In 1863, H. C. Wood7 claimed distinctly that sunstroke is a fever due to the development of a poison in the blood, and gave to the disease the name of thermic fever. To R. Cresson Stiles is due the credit of having first proven8 the possibility of producing in animals a sunstroke with symptoms and pathological changes similar to those which occur in man. He also came to the conclusion that the symptoms are the results of the direct action of heat, especially upon the muscular system. He says: “The dilatation of the capillaries is explicable by the direct effect of the heated blood upon the muscular fibres of the arteries and the arterioles. The cerebral symptoms and the full and forcible pulse may also be due to this dilatation.” George B. Wood, in the sixth edition of his Practice of Medicine (Philadelphia, 1866), wrote an elaborate article upon the disease, giving it the name of heat fever, and affirming that it “is, I believe, strictly an idiopathic fever.” He further asserts: “In heat fever all the organs, the brain, heart, lungs, stomach, kidneys, etc., are excessively stimulated by the great heat, and all exhibit disorder and at length depression of their functions.” The article of George B. Wood was not based upon experimental researches, but upon a very philosophic rendering of the clinical phenomena, and was a carrying out of the ideas which had permeated the medical teaching of the Pennsylvania Hospital.
6 New York Med. Journ., vol. xiii. p. 53.
7 Amer. Journ. Med. Sci., October.