BACTERIA IN CROUPOUS PNEUMONIA. 309 



in the body of an immune animal, as a result of protective inocula- 

 tions, upon which the immunity of these animals depends, is also a 

 proteid, which they call anti-pneumotoxin. This they isolated from 

 the blood serum of immune animals. By experiment they were able 

 to demonstrate that the blood serum containing this protective pro- 

 teid, when injected into other animals, rendered them immune ; and 

 also that it arrested the progress of the infectious malady induced by 

 inoculating susceptible animals with virulent cultures of the micro- 

 coccus. When injected into the circulation of an infected animal 

 its curative action was manifested by a considerable reduction of 

 the body temperature. 



