Serological Differentiation of Bacillus tetani. 



153 



saline. The deposit was examined microscopically to determine the presence 

 of endsporing bacilli in overwhelming numbers. 



The saline suspension was standardised by the opacity method and exposed 

 to the action of agglutinating sera specific to the three toxic types, and also 

 to sera si)ecific to B. sjm'ogenes, B. pseudo-tetani, and Tetanoid No. 1 bacillus. 



The eight-day broth culture was inoculated into animals in a dose of 

 0-5 c.c. 



Owing to the difficulty of obtaining guinea-pigs for this purpose I was 

 compelled to employ rats. The animals were inoculated subcutaneously 

 at the root of the tail. Diagram Y (p. 154) illustrates the results 

 obtained. 



The points calling for comment in these results are : — 

 {a) The agglutination and toxicity tests agree in all but two cultures — 84 

 and 89. 



Whether these two cultures represent a fourth type of the bacillus or not 

 I cannot at present state definitely, but from the late development of 

 symptoms of tetanus in the animals inoculated with the broth cultures 

 corresponding to these, it appears to me to be probable that the inocula 

 contained but few B. tetani and the agglutination was masked by the overplus 

 of other organisms present in the suspension. 



Q}) Up to the present the type of B. tetani most frequently obtained from 

 wound exudates in cases of tetanus among men who have received prophyl- 

 actic inoculation, corresponds to the culture designated Type II. The 

 number of cultures examined is at present too small to permit of any 

 far-reaching conclusion being drawn from the results obtained. 



The following agglutination results with four toxic cultures are of peculiar 

 interest, in that these organisms were derived from wounds in men not 

 suffering from tetanus. 



