DISEASES OF THE INTESTINES. 237 



of an acute or chronic nature. It is not established as yet 

 whether this affection can be communicated from one horse 

 to another. In most cases dysentery occurs as an indepen- 

 dent affection; sometimes, however, it supervenes on an 

 attack of ordinary diarrhoea. Among the chief causes of 

 this malady in the horse are : 



1. Malhygienic conditions, such as overcrowding, vitiated 

 air supply, and exposure to noxious emanations. 



2. Insufficient or had food and foul water. 



3. Exposure to cold and damp, overwork, and all other de- 

 pressing agencies. 



4. Malarial poison arising from vegetable decay. 



This is especially prevalent in low-lying marshy tracts 

 and in shady places. 



We have, as yet, no evidence that dysentery owes its 

 origin to the entry of any specific germ into the system, 

 already perhaps in an unhealthy depressed condition, but 

 this seems not at all unlikely. 



In the horse we have no proof that this disease ever arises 

 from direct infection from another animal. 



Symptoms. — The frequent passage of liquid faeces may 

 first attract notice, or, in other instances, febrile manifesta- 

 tions, debility, and rapid prostration may precede the 

 frequent alvine discharges. 



Rigors are common throughout the disease in many cases. 

 The pulse is accelerated, the internal temperature is elevated, 

 thus distinguishing this affection from simple diarrhoea. 



Sometimes the disease begins insidiously, and we may 

 not suspect the true nature of the affection in the first 

 instance. But as the disease advances the appetite becomes 

 more impaired ; there is great depression, thirst, tympanitis 

 not unfrequently, general wasting, marasmus, and marked 

 prostration. 



The fccces are thin and watery and offensive, and are 



