16 BACTERIOLOGY : 



method has not been as thoroughly developed in other diseases, 

 but has shown a value in aiding the identification of cases of 

 cholera, glanders, malta fever/ tuberculosis, leprosy, relapsing 

 fever and other diseases. Considering that the method is yet in 

 its infancy, the results obtained have been surprisingly accurate. 

 The test is performed with or without the microscope, the former 

 having the -advantage of quickness and greater accuracy. The 

 main difficulty that the practitioner will find with this method is 

 the difficulty of keeping on hand fresh cultures of the bacilli. The 

 advantages of emulsions of dead bacilli are readily apparent, but 

 thus far they have proven less reliable than the fresh cultures. 



A final, simple and practical method of diagnosis is by the in- 

 jection of bacterial products into the affected animal. Tuber- 

 culin, a glycerin extract of tubercle bacilli, has proved to be a 

 most reliable agent for diagnosing tuberculosis. Unfortunately, 

 its tendency to exacerbate this affection has largely precluded its 

 use in the human family. Mallein has also proven successful in 

 diagnosing glanders in horses. 



Prophylaxis and Treatment. Two main classes of bacterial 

 remedies have been developed, namely, those obtained directly 

 from the micro-organism and those indirectly obtained by the ac- 

 tion of bacterial products upon animals. To the first class be- 

 long the toxins -and vaccines ; to the latter class the antitoxic and 

 bactericidal serums. The former <have been of chief value as 

 prophylactic 'and immunizing agents, but, as yet, have not re- 

 vealed the curative powers of the latter class. Upon the other 

 hand, the antitoxins have more transient immunizing powers 

 than the toxins or vaccines. Protective inoculations or vaccin- 



