SUNSTEOKE. 571 



the hot months the len^h of their stages to distances of IJ or 1^ 

 miles, almost entirely stopped among their horses the occurrence 

 of sunstroke, which, with longer stages, had previously been 

 frequent; although they did not alter the length of the daily 

 average journey of 12J miles. The danger of sunstroke from work, 

 either in saddle or harness, during hot weather, is greatly increased 

 by keeping the animal exposed to the direct rays of the sun some 

 time before starting. The history of many cases of sunstroke I 

 have seen, suggests the conclusion that the effect the direct rays of 

 the sun, when very hot, have on the skin, is, at first, that of 

 checking, instead of stimulating, the excretion of perspiration, so 

 that the animal in place of being cooled down by copious evapora- 

 tion from the skin, feels as does a man who is in the hot stage 

 of an attack of intermittent fever. But, as I have often found 

 when riding and driving long distances during mid-summer in 

 India, if we apportion the work of, say, the first hour, so that the 

 horse's skin recovers its normal function, acts freely and then is 

 allowed to dry while the animal is kept at an easy pace, he will 

 after that, if in " condition," be able to go at least three times the 

 distance he could have done, had he been given no preliminary 

 preparation. 



Deprivation of water is a strong predisposing cause of sunstroke, 

 in that it cuts off the supply of the fluid by the evaporation of 

 which, in the form of perspiration, the body is kept cool. Among 

 other predisposing causes, are : residence in a stable which is ill- 

 ventilated, crowded, or does not afford adequate protection against 

 the direct rays of the sun ; too much corn ; and an insufficiency 

 of green food. 



CLIMATE. — ^The climate most favoxirable to the development of 

 sunstroke, is a very hot one which, like that of Calcutta, has a 

 sufficiency of moisture in it to check the cooling influence, on 

 the body, of the evaporation of perspiration. The glare of the sun 

 off buildings and roads appears to help in bringing on an attack. 



BREED AND TEMPERAMENT.— The horses most predisposed 

 to sunstroke are naturally those bred in a temperate or cold 

 climate, especially if they have little or no Eastern or thorough- 

 bred blood in their veins. From my own observations I believe 

 that the internal temperature of Indian Country Breds, is, as 

 a rule, lower than coarse-bred horses, whose skin and hair are 

 thicker and their sweat glands less active than those of Indian 

 Country Breds, Arabs, and thoroughbreds. Consequently they 

 cannot keep themselves so cool, as better bred horses. I liave 



