208 Manual of Veterinary Microbiology, 



should be preferred for vaccination. The immunity 

 obtained lasts only one year, but this term is sufficient 

 for the needs of breeding and fattening.* 



Pneumo-enteritis of the pig, hog cholera. 



Pneumo-enteritis of hogs is an infectious and con- 

 tagious disease which was long confounded with 

 rouget. It was described, in the first place, in Amer- 

 ica, by Salmon under the name of hog cholera; in 

 France it has been investigated by Riestsch and Jo- 

 bert, and Cornil and Chantemesse, in connection with 

 the epizootics at Marseille and at Gentilly ; it was 

 studied by Selander in the swine of Sweden and 

 Denmark. 



This disease chiefly attacks young animals and is 

 nearly always fatal. It manifests itself by symptoms 

 the description of which differs somewhat in the dif- 

 ferent countries in which it has been observed. 



According to Salmon, the disease maybe acute or 

 chronic. In the latter case inappetence is observed 

 along with persistent diarrhoea and slow emaciation 

 of the diseased animals. When the disease is acute 

 the diarrhoea is more intense and sanguinolent. In 

 both cases the intestine is much altered, principally 

 the large intestine. The latter presents ulcerations 

 and considerable thickening of its mucosa when the 

 disease has been slow; when the evolution has been 

 rapid the lesions assume a hemorrhagic character and 

 aflfect not only the caecum and large colon, which are 



* [Lorenz has introduced a method of protective inoculation by 

 the use of the blood-serum of swine which have previously been 

 immunised against rouget. {Centralblatt fur Bacteriologie, xiii — 11, 

 12.)-D.] 



