546 NERVOUS DISEASES. 



dies in a few days from exhaustion, brought on by excitement and 

 other nervous derangement. Generally speaking, as long as the 

 animal is able to keep on his legs, he shows but little signs of 

 constitutional disturbance. Sometimes, the attack is so mild, that 

 the horse continues capable of being ridden and driven, although 

 he will exhibit a certain loss of power in bearing weight, and, also, 

 in bringing his hind legs forward. 



The lameness from spinal congestion closely resembles that from 

 kumree (p. 542). 



If the animal does not die from the severity of the attack, the 

 disease will generally run a chronic course, and the horse may 

 slightly improve with time ; may get comparatively well ; or may 

 become gradually worse, and die after a few months. 



CAUSES. — There seems to be but little doubt that this paralysis 

 is caused by chill, and is due to congestion of the spinal cord, on 

 account of which there is an exudation of watery fluid from the 

 blood-vessels into the spinal canal, with consequent paralysis from 

 pressure on the cord. The all but universal idea in India is that 

 this paralysis is caused by the influence of cold winds ; hence, its 

 common designation, '' a stroke of the wind." It is a well-estab- 

 lished fact that in places where spinal congestion is rife, cases are 

 especially liable to occur when a cold, dry, night wind springs up 

 after a sultry day. In one instance its recurrence was stopped in 

 a native cavalry regiment, where it had been prevalent, by building 

 a wall high enough to shelter the horses from wind. The baneful 

 effects of chill, particularly in warm climates, are far greater when 

 the air is laden with moisture, than when it is comparatively dry ; 

 because, under the former condition, evaporation from the skin is 

 checked, sweat bedews the body, and the superficial vessels are 

 congested. If, when in this state, the animal is exposed to a cold, 

 dry wind, there will be contraction of the blood-vessels of the sur- 

 face of the body, with a corresponding rush of blood to the under- 

 lying tissues, which determination of blood may cause congestion 

 of the vessels of the spinal cord, with consequent paralysis. The 

 effect of the direct and powerful rays of the sun, probably, pre- 

 disposes the cord to become thus affected, or may even bring about 

 degenerate changes in that nerve centre. 



POST-MORTEM APPEARANCES.— The appearances of recent 

 cases of this disease are those of congestion of the cord at the 

 loins, with, consequently, a large amount of serum (over 12 oz. in 

 one case) in the spinal canal. Observers are generally agreed 

 tliat in old cases — ^no distinction being made between it and 

 kumree — there is always softening of the cord of that part. 



