344 BACTERIOLOGY. 



cultures of comma bacilli to cholera patients. 

 Koch's experiments with tuberculin, in 1890, 

 are the best known experiments of this class, 

 but the results obtained have not approxi- 

 mately fulfilled the hopes aroused. Such 

 favorable results with this substance as have 

 been recorded may be attributed to the power 

 of tuberculin to excite inflammation, (p. 313), 

 a point wholly missed by Koch and discovered 

 by Hueppe and Scholl. F. and G. Klemperer 

 have used the proteids of Diplococcus lanceo- 

 latus to combat pneumonia, and E. Frankel 

 those of the typhoid bacteria, as protection 

 against typhoid fever, but without specially 

 successful results. 



In those cases which are to be regarded as 

 instances of rapid immunization it is necessary 

 to meet any increase in the intensity and dura- 

 tion of the disease, by administering stronger 

 or more potent doses of the immunizing sub- 

 stance, so that the danger of poisoning the 

 organism is increased. Acting upon his con- 

 ception of passive immunity, Behring thought 

 it possible to avoid completely this danger, 

 and to cure certainly and without risk of harm, 

 by introducing the protective serum, even after 

 successful infection had been brought about. 

 This is the real significance of the serum ther- 

 apy, although, from the beginning, it has been 



