146 • PRESSURE AND RADIATION 



6. The air in human hair, especially black hair, under the influence of the 

 tropical sun, acquires temperatures far above those compatible with life. 



He also states that increased body temperature probably accounts for many 

 of the accidents called sunstroke or heat-stroke, and he thinks that an excessive 

 and continued watery evaporation from the skin, while avoiding a rise of body 

 temperature, may lead to collapse, unless the lost water is replaced. 



We believe that it is possible that direct radiation from the sun 

 can bring about sudden death and congestion of the meninges of 

 the brain. The connection between sunstroke and the chemical 

 rays requires more investigation; but, whatever this may produce, 

 there is no doubt that if the improperly protected head is exposed 

 to radiation from the sun, headache and a feeling of illness is often 

 produced, and that therefore adequate protection is required. 



As is well known, monkeys prefer the shade to the sun's rays, and 

 seem to understand the danger therefrom; and yet no one is afraid 

 - of monkeys dying from the heat in laboratory outhouses, though its 

 effect on other kinds of tropical animals, such as gerbils, is a matter 

 of bitter experience, leading to the loss of strains of trypanosomes. 



We hold, however, that there is no clinical difference between 

 heat-stroke and sunstroke, and therefore these will be considered 

 as one and the same disease in the clinical section of this work 

 (see Chapter LVL, p. 1449). 



ELECTRICITY. 



Thunderstorms are often of extreme violence in the tropics, and death from 

 lightning-stroke is much commoner than in the Temperate Zone ; but the signs 

 of lightning-stroke are exactly the same as those usually recorded in books 

 on general surgery, and need not be repeated here. 



REFERENCES. 



The most valuable work for general knowledge is Pembrey and Ritchie 

 (1913), 'Textbook of General Pathology,' where Haldane's articles on respira- 

 tion will be found most useful. 



Pressure. 



Hill, Caisson Disease. London. (A very important publication.) 



Radiation. 



Brown, Carnegie (1906). British Medical Journal (Degeneration of the 



Myocardium in Hot Climates), i. 1462-1463. 

 Cleaves {1904). Light Energy, pp. 253, 254, and pp. 798-801. 

 Duncan (1904)- Journal of Tropical Medicine. (1908). Journal Royal 



Army Medical Corps, xi., 71. 

 Fayrer (1893). Davidson's Hygiene and Diseases of Warm Chmates, p. 691. 



(1907). AUbutt and Rolleston's System of Medicine, II., ii. 771-782. 

 Freund (1904). Radiotherapy. London. 



Electricity. 



Adamson (1900). Journal of Tropical Medicine and Hygiene (Interesting 

 account of lightning stroke), January, 147. 



