362 PATHOGENIC BACTERIA. 



formed tissue, extend to the chest-wall, and form external 

 sinuses. Or it may penetrate the diaphragm and invade 

 the abdominal organs, causing an interesting and charac- 

 teristic lesion in the liver and other large viscera (see 



Fig. 77)- 



Microscopically the lesion consists chiefly of a round- 

 cell infiltration with circumscribing granulation-tissue 

 leading to the formation of cicatricial bands. In the 

 form known as "wooden tongue" the disease runs an 

 essentially chronic course, with the production of consid- 

 erable amounts of connective tissue. 



But few cases recover, the disease terminating by death 

 from exhaustion or from complicating pneumonia or 

 other organic lesions. 



