74 ' BACTERIOLOGY. 



made to immunize animals by the injection of small 

 amounts of the toxin, and have been to some extent 

 successful. It is not possible to immunize man in this 

 way. 



Diagnosis The diagnosis of glanders may be made in sev- 



eral ways. The discharges or the pus may be injected 

 into the peritoneal cavity of guinea-pigs. If the 

 bacillus of glanders is present the testicles become 

 x swollen and painful in two to five days. A test may 

 be made for the presence of substances in the blood- 

 serum that will agglutinate the bacilli of glanders. It 

 is done in the same manner as the Widal reaction for 

 typhoid fever. Finally, the toxin of the bacilli made 

 from cultures and called mallein may be injected under 

 the skin of suspected cases. If glanders is present it 

 produces a reaction marked by fever and tenderness 

 about the point of inoculation. The principle upon 

 which this reaction rests is the same as in the tuber- 

 culin reaction. 



THE BACILLUS OF INFLUENZA. 



Influenza, or grippe, is a highly infectious disease 

 that spreads with great rapidity. It is caused by the 

 influenza bacillus. In' 1889 an epidemic of grippe 

 started in Russia and in a year's time extended com- 

 pletely around the world. This bacillus is smaller than 

 the bacilli we have studied so far. It is not motile 

 and does not form spores. It grows only in the pres- 

 ence of oxygen. It is difficult to cultivate unless fresh 



