COMPLICATIONS 33 



tics in common. All are of a subvirulent nature, 

 usually depending on other influences or predis- 

 posing causes to enable them to exert their patho- 

 genic powers, and all frequently take advantage 

 of the lesions produced by hog cholera virus, in 

 which they establish themselves, changing the 

 course of the disease, and rendering autopsies 

 puzzling and inconclusive. 



There are several other organisms that have 

 been associated with hog cholera, either as com- 

 plicating influences or probable causes, but some 

 of these normally lead a saprophytic existence, 

 and with our present knowledge we are unable to 

 assign to any one of them a definite pathogenic 

 role. B. coll communis and other members of the 

 group, together with various streptococci and 

 micrococci may often be found in lungs of hogs 

 that have died of a terminal pneumonia brought 

 on by hog cholera. Spirochceta lnyos (King) is 

 sometimes found in the blood and intestinal le- 

 sions of hogs suffering with cholera, and B. py- 

 ogenes suis is found in various suppurating lesions 

 in swine, some of which have died in hog cholera 

 outbreaks. The collective primary and secondary 

 effects of all the organisms considered in this 

 chapter, together with the changes produced by 

 hog cholera virus go to make up the symptom- 

 complex which, conveniently but unfortunately, 

 has come to be known as " mixed infection, " and 



