BACILLI OF THE COLON-TYPHOID-DYSENTERY GROUP 681 



precluded the possibility of an antitoxin therapy, such as that which has 

 been successful in diphtheria. In the light of our present knowledge 

 of the poisonous products of the typhoid bacillus it seems but natural 

 that attempts by earlier investigators to apply the -principles of Beh- 

 ring's work to typhoid fever were doomed to fail. Attempts to employ 

 specific bactericidal and bacteriolytic sera for therapeutic purposes in 

 this disease have also been without favorable result. 



Active Prophylactic Immunization. We have seen that work by 

 Pfeiffer and Kolle and later by many others has shown that it is com- 

 paratively easy to immunize animals actively against typhoid infection 

 by the sytematic injection of graded doses, at first of dead bacilli, later 

 of fully virulent live cultures. Attempts to apply these principles pro- 

 phylactically have been made recently on a large scale by Wright and 

 his associates upon English soldiers in South Africa, and by German 

 observers in East Africa. 



The first recorded experiment of this sort which was done upon 

 human beings was that of Pfeiffer and Kolle, 115 who in 1896 treated two 

 individuals with subcutaneous injections of an agar culture of typhoid 

 bacilli which had been sterilized at 56 C. The first injection was made 

 with 2 cmm. of this culture. Three or four hours after the injection the 

 patient suffered from a chill, his temperature gradually rose to 105 F., 

 and there was great prostration and headache, but within twenty-four 

 hours the temperature had returned to normal. 



This experiment showed that such injections could be practiced upon 

 human beings without great danger. 



Simultaneously with the work of Pfeiffer and Kolle, Wright 116 

 conducted similar experiments on officers and privates in the English 

 army. 



The actual number of persons treated directly or indirectly under 

 Wright's 117 supervision in an investigation covering a period of over four 

 years comprised almost one hundred thousand cases. The methods 

 employed by Wright have been modified several times in minor details; 

 the principles, however, have remained consistently the same. In the 

 first experiments Wright employed an agar culture three weeks old, 

 grown at 37 C., then sterilized at a temperature below 60 C., and pro- 

 tected from contamination by the addition of five-tenths per cent of 



115 Pfeiffer und Kolle, Deut. med. Woch., xxii, 1896, xxiv, 1898. 



116 Wright, Lancet, Sept., 1896. 



117 Wright and Semple, Brit. Med. Jour., 1897; Wright and Leishmann, Brit. Med. 

 Jour., Jan., 1900. 



