996 VETEEINAEY HYGIENE 



pressure may lead to hemorrhages, especially in tissues 

 like the membrane of the cord, followed by immediate 

 paralysis. 



Winds are infinitely more likely to produce disease than 

 cold without wind, and the cause of this has been previously 

 touched on. Of the various factors in climate, viz., heat, 

 cold, reduction or increase in pressure, and rain, nothing 

 in our opinion can approach cold wind as a pathological 

 factor. • 



In cold weather it robs the body of heat, in warm 

 weather or over a sweating surface it does the same thing, 

 in both cases it may produce that common but remarkable 

 pathological condition known as ' chill,' though it is far 

 more likely to produce this when blowing over a hot wet 

 surface than when playing on a cool dry one. 



In the whole range of climatic causes we are convinced 

 that a cold wind stands pre-eminent ; through the influence 

 of chill it is responsible for the production of inflammatory 

 chest diseases in cold climates, and to congestion of the 

 abdominal viscera in hot. There are even forms of paralysis 

 in tropical countries like India attributed to wind ; and in 

 horses the affection is popularly known as ' wind-stroke.' 

 Its pathology is quite unknown, and the wind may have no 

 more influence in its production than the moon has in the 

 production of ophthalmia. 



Animals at liberty instinctively turn their backs to the 

 wind especially when this is associated with rain. During 

 heavy rain and wind the back is arched, the legs drawn 

 together, the tail pressed into the quarters, the head drawn 

 back, and the neck arched on its upper surface, as if the 

 muscles were unable to resist the elastic recoil of the liga- 

 mentum nuchs. 



The influence of rain in the production of disease is 

 mainly indirect. Two pests like anthrax and South African 

 Horse Sickness are practically only seen during the rainy 

 season, but the influence of the rain in the latter disease is 

 to rouse into activity the intermediate host. Insect life 

 during the rains under the influence of heat and moisture,. 



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