230 Veterinary Medicine. 



former. With the excess too, there is always present a large 

 amount of toxins, ptomaines and other more or less poisonous 

 products, which, acting on the intestinal mucosa or even on the 

 system at large, tend to reduce its vitality and to lay it open to 

 the attacks of bacteria which had otherwise remained perfectly 

 harmless. Porcher and Desoubry, Achard and Phulpin and 

 Wurz have shown experimentally that intestinal microbes can 

 enter the chyle and blood from even a healthy bowel. The 

 .streptococcus of pneumoenteritis equi of Galtier and Violet ap- 

 pears to be a common fodder and intestinal microbe, which has 

 become pathogenic, because of its excess or on account of a lack 

 of resistance on the part of the animal. In the same way the 

 various intestinal cocci and the common colon bacillus may be- 

 come pathogenic when the normal antagonism of the bowels and 

 their contents is lessened. 



In the same way stagnant and septic water may be harmless to 

 one animal of great vigor and good tone and pathogenic to 

 another which lacks these qualities ; or the excess of the ferment 

 and its toxins may overcome the natural resistance of the animal. 

 The lack of the natural antiferments of the intestine, pepsin 

 and hydrochloric acid, on the one hand and bile on the other, 

 will also conduce to multiplication of the. microbes and their 

 products, so that they can successfully attack the mucous 

 membrane. 



Other accessory causes operate more or less, thus any impair- 

 ment of the process of mastication, through disea,sed teeth or 

 jaws tends to the escape of undigested food through the stomach, 

 as a .specially favorable culture media for the microbes, and irri- 

 tants of the mucosa. 



Lesions. As the disease very often implicates the stomach 

 (gastro-enteritis), the usual lesions of gastritis will be seen. 

 Mo.st commonly the lesions are best marked in the small intes- 

 tine, and again in other cases in the colon, but usually there is 

 more or less change in all parts of the intestinal canal. The 

 .small intestine • is almost devoid of aliments and the muccsa 

 deeply congested in patches or striae, with at points thickening, 

 softening so that it crushes under the finger, hemorrhagic dis- 

 coloration, and even ulceration, and necrotic changes. It is 

 covered with a layer of mucus, thin and mucilaginous or thick 



