182 DISEASES OF THE BRAIN. 



[The condition known under the term " sunstroke," or better, 

 " heatstroke " (for the direct action of the sun's rays is by no means 

 essential to it), used formerly to be ascribed to a hyperaemia of the 

 brain ; a belief which has now been completely exploded by experi- 

 ments upon animals and by post-mortem examinations. It is now 

 known, from the researches of Obernier, that in this disease there is 

 a serious derangement of the heat-producing function and a great 

 rise in the bodily temperature, which in extreme cases may reach 

 109 or 110 Fahr. Absolutely nothing as yet is known, however, 

 of the anatomical lesions upon which sunstroke depends. It was 

 formerly ascribed to grave alterations in the blood, to its over-acidity 

 by overloading with carbonic and lactic acid, to destruction of its 

 red corpuscles, to accumulations in it of urea, and the like. Koester 

 in one case has found a haemorrhage in the right superior sympa- 

 thetic ganglion, and in the right sympathetic itself, as well as 

 smaller extravasations about and in the two vagi, and thinks we 

 should look for the derangements in the vasomotor and respiratory 

 nervous systems. Arndt seeks for an anatomical basis for the disease 

 in the so-called "turbid swelling" (trilben Schwettung) developed 

 in the brain, liver, kidneys, and other tissues, under the influence 

 of the enormously high temperature, just as it occurs in high fever 

 from other causes. The different symptoms presented during life 

 may depend upon the degree in which the turbid swelling has at- 

 tacked individual organs. In milder cases the temperature is below 

 104 ; the mind is muddled, the chest oppressed and uneasy, the pulse 

 very frequent, the heat great, the skin moist, and there is a general 

 but moderate feeling of languor. . If relief cannot be gained through 

 water-drinking and quiet, graver symptoms appear. The temper- 

 ature then rises above 104, the pulse to 130 or 140 ; the sweating 

 becomes profuse and the thirst distressing. The patient loses con- 

 trol over himself,- and is oppressed by fulness of the head, dizziness, 

 sensory delusions, and precordial distress. He is forced to sit down, 

 or else sinks suddenly unconscious, and lies with flickering imper- 

 ceptible pulse and sunken features. Sometimes there are epilepti- 

 f orm fits. Although under proper treatment many very severe cases 

 recover, yet the number which end fatally, particularly during the 

 marches of armies in hot weather, is sometimes large. Many pa- 

 tients improve at first, and then relapse unexpectedly. This fact, as 

 well as the experience that recovery after sunstroke is slow, that it 

 has many sequelae, such as vague pains, disposition to faint, indi- 

 gestion, unnatural drowsiness, and the like, which are often obsti- 

 nate, and the circumstance that sometimes there remains a psychical 

 irritability or a permanent impairment of intellectual function, all 



