•084 DYSEXTERY. 



Leen encountered in young horses somewhat exposed to adverse 

 clmiatic conditions, and in all varieties where indifi'erent sanita- 

 tion, defective dietary, and other lowering agencies have been 

 in operation. 



h. Causation. — Unlike the practitioner of human medicine, 

 the veterinary surgeon is not in the position, with respect to 

 dysentery, to affirm that there are just grounds for attributing 

 its appearance to direct infection — that is, to the importation 

 into the healthy of specific disease-germs. 



Both as predisposing and directly inducing factors — when 

 sufficiently long maintained — we are disposed to place — 

 (1) All depressing influences, whether of work, exposure, in- 

 sufficient food, and generally bad sanitation. (2) Noxious 

 emanations, chiefly animal, resulting from over-crowding, and 

 tending, by their toxic influence, to induce haemal contamina- 

 tion. (3) Probably malarial influences, generated in particular 

 situations where horses may be retained during improper 

 periods. 4. The previous existence of functional disturbance — 

 -diarrhoea — which, from improper treatment or association 

 with some constitutional cachexia, or already existing diseased 

 action, as intestinal parasitism, may offer a favourable oppor- 

 tunity for the development of the peculiar textural changes. 



That any of these individually may tend to the production 

 of dysentery is probable ; in practice, however, it is usual to 

 find that two or more of them have been associated with its 

 appearance. 



c. Anatomical Characters. — Although in a general sense the 

 leading anatomical features may be said to be that of inflam- 

 mation of the bowel, with gangrene and ulceration, when we 

 come carefully to examine this condition it is found that the 

 morbid action has certain peculiarities upon which its in- 

 dividuality depends ; also it is to be remembered, that although 

 possessing in all instances certain great generic features, there 

 ^'ire yet many instances of variation both as to extent and 

 •character. Rarely have we more than portions of the bowel 

 exhibiting the diagnostic lesions which are irregularly scattered 

 over the whole extent. At first, and previous to necrotic 

 changes and the production of an ulcerous sore, we may observe 

 small spots or elevations of the membrane projecting from a 

 somewhat swollen and hypememic base ; these papules on the 



