CEREBRAL HEMORRHAGE. — This is probably the disorder for which insola tion is differentiated with some diffi culty. The absence of hemiplegia is con sidered as reliable sign by Flint.
Three types of sun-stroke specified. The cerebrospinal, characterized by symptoms of intense congestion—by in jection of the face and conjunctiva, by stertor, coma, and convulsions; the syn copal, or cardiac, type, made manifest by pallor of face and profuse perspiration, death taking place by arrest of the heart; and the pulmonary form, in which, in addition to some of the symp toms pertaining to the other two there are anxiety, dyspncea, and asphyxia. Sun-stroke usually arises under condi tions of mental or physical overactivity in conjunction with undue exposure to beat and a suppression of the secretions, the disease being dependent upon reten tion, in the system, of toxic products of retrograde metamorphosis. Martin (La Sem. Med., Sept. 16, '91).
Etiology.—IA]xcessive heat in any form is usually considered as the main factor in the production of insulation. It may not only occur in the street, but also in a boiler-room, a laundry, etc., showing that heat is the predominant factor. Heat-exhaustion may be brought about by excessive exertion under unfavorable conditions, while sun-stroke is due to excessive heat and occurs during the hottest season of the year. The latter exhibits remarkable endemic characters, in that it is extremely prevalent in one locality, in another is totally absent, though the region may be quite adjacent and under precisely similar climatic influences; again, its ravages in differ ent years vary immensely and quite ir respective of heat. (Sainbon.) Exercise strongly favors production of heat-stroke. Excessive temperature acts directly on the nervous system, and not by inducing autointoxication or coagula tion of muscle-fibre. Laveran (Bull. de l'Acad. de Med. de Paris, Nov. 27, '94).
Insolation is due, not to discrete local lesions, but rather to some direct effect on the brain as a whole. Jackson (Bos ton Med. and Surg. Jonr., Feb. 4, '97).
According to Phillips, meteorological conditions predispose to sun-stroke, and these involve high temperature, relative humidity, wind, and climatological char acteristics, as well as the direct rays of the sun. The attack is no more depend
ent on high temperature and direct in solation, he thinks, than it is on low relative humidity.
The reduction of physical resistance to the action of heat upon the nerve centers and a secondary disturbance of metabolism probably at the bottom of these cases. Thus fatigue,—mental and physical,—insufficient food, unsanitary surroundings, and worriment arc all noted as predisposing factors. Alcohol ism is particularly active in this respect.
The colonial governments of Australia having asked the medical board to issue appropriate instructions as to prophy laxis from sun-stroke, the fact was elicited that, of all predisposing causes, undue indulgence in intoxicating liquor is the most common and the most dan gerous. Further, that during the attack it is dangerous to employ intoxicants as a remedy. Editorial (Brit. Med. Jour., June 20, '96).
Clinical and pathological study of S03 cases in which the main factor was shown to be an autointoxication, with heat as a contributing cause. Lambert and Van Gieson (Medical Record, July 4, '97).
Of 465 cases whose histories were known out of a total of 841 eases, 30 per cent. were alcoholic, 50 per cent. moder ate drinkers, and 20 per cent. teetotalers; while of 70 deaths, 60 per cent. occurred in alcoholic patients, 30 per cent. in moderate drinkers, and only 10 per cent. in teetotalers. Phillips (Inter. Med. Mag., Aug., '97).
Males are more frequently affected than females, and children—though less frequently attacked—are not free from the disorder, especially when the head is exposed to sun-rays.
Three cases of thermic fever in infants, each about one year old. The cases de veloped during the heated term, amid the most unfavorable surroundings. Each presented vomiting, diarrhoea, high temperature, and symptoms of profound depression. The cold wet-pack was used in treatment, with most successful re sults. Illoway (Med. News, Aug. 8, '92).