STUDIES UPON AGGLUTINATION 



41 



In my experiments (table 2) using Bad. lyphosum and Bad. 

 paratyphosKtn A and specific immune senmi, agglutination was 

 strongest with tests containing 0.05 to 0.1 per cent formalin; 

 0.3 per cent showed sUghtly less agglutination and 1 per cent 



TABLE 2 



Standardization of formalin concentration in plain broth culture media to promote 

 specific serum agglutination. (Cultures of twenty-four hours at SyC.) 



Keyt:5, complete; 4, almost complete; 3, weak; 2, very weak; 1, trace ;0, nega- 

 tive agglutination. 



produced about the same results as those obtained without forma- 

 lin. With Bad. paratyphosum B, agglutination by specific 

 serum in the presence of 0.05 to 0.3 per cent formalin was about 

 the same as, or slightly stronger than, without formalin; with 



