VACCINES IN TREATMENT OF DISEASE 247 



apy, the belief has been repeatedly expressed 

 that little can be expected of bacterial vac- 

 cines in generalized infections. So far as pres- 

 ent knowledge takes us in such infections, the 

 tissue-cells are busily engaged in combating the 

 poisonous groups resulting from the death of 

 the bacterial cells in considerable quantity in 

 the body. In most instances, their efforts are 

 successful and recovery takes place. To thwart 

 their efforts by adding more bacterial protein, 

 when already worked to capacity, would appear 

 unjustifiable. 



PREPARATION OF BACTERIAL VACCINES 



Bacterial vaccines are prepared in our labo- 

 ratories from cultures of pathogenic bacteria 

 which have been grown upon suitable solid me- 

 dia under the most favorable conditions. Sever- 

 al strains of the respective bacteria are used; 

 for it has been demonstrated clinically, as well 

 as in the laboratory, that different cultures of 

 the same microorganism may vary widely in 

 biochemic properties; and that most vaccines 

 should be polyvalent in order to possess the 

 greatest efficiency. Polyvalent means that the 

 suspension contains several cultures of the 



