238 DISEASES OF THE HOESE. 



This condition consists in a poisoning and depression of the ner- 

 vous system from eating or drinking feed or water containing poison 

 generated by mold or bacteria. It has been shown to be owing to 

 eating damaged ensilage, corn, brewers' grains, oats, etc., or to drink- 

 ing stagnant pond water or water from a well contaminated by sur- 

 face drainage. Horses at pasture may contract the disease when 

 the growth of grass is so profuse that it mats together and the 

 lower part dies and ferments or becomes moldy. 



In England a similar disease has been called " grass staggers," due 

 to eating rye grass when it is ripening or when it is cut and eaten 

 while it is heating and undergoing fermentation. In eastern Penn- 

 sylvania it was formerly known by the name of " putrid sore throat " 

 and " choking distemper." A disease similar in many respects which 

 is very prevalent in Virgina, especially along the eastern border, is 

 commonly known by the name of "blind staggers," and in many of 

 the Southern States this has been attributed to the consumption of 

 worm-eaten corn. Horses of all ages and mules are subject to this 

 disease. 



SyTTiptoms and lesions. — The symptoms which typify sporadic or 

 epidemic cerebrospinal meningitis in man are not witnessed among 

 horses, namely, excessive pain, high fever, and early muscular 

 rigidity. In the recognition of the severity of the attack we may 

 divide the symptoms into three grades. In the most rapidly fatal 

 attacks the animal may first indicate it by weak, staggering gait, 

 partial or total inability to swallow solids or liquids, impairment of 

 eyesight; twitching of the muscles and slight cramps may be ob- 

 served. As a rule, the temperature is not elevated— indeed, it is 

 sometimes below normal. This is soon followed by a paralysis of 

 the whole body, inability to stand, delirium in which the animal 

 sometimes goes through a series of automatic movements as if trot- 

 ting or running; the delirium may become very violent and the un- 

 conscious animal may bruise his head very seriously in his struggles ; 

 but usually a deep coma renders him quiet until he expires. Death in 

 these cases usually takes place in from 4 to 24 hours from the time 

 the first symptoms become manifest. The pulse is variable during 

 the progress of the disease ; it may be almost imperceptible at times, 

 and then again very rapid and irregular; the respirations generally 

 are quick and catching. In the next form in which this disease may 

 develop it first becomes manifest by a difficulty in swallowing and 

 slowness in mastication, and a weakness which may be first noticed 

 in the strength of the tail ; the animal will be unable to switch it or 

 to offer resistance when we bend it up over the croup. The pulse ia 

 often a little slower than normal. There is no evidence of jpain ; the 

 respirations are unchanged, and the temperature little less than nor- 

 mal; the bowels may be somewhat constipated. These symptoms 



