52 o. isHii 



The specific serum agglutination in this medium was also weak. 

 Therefore the use of alkaline media for Bad. typhosuvi is not 

 favorable for agglutination tests. According to Park and Wil- 

 liams, and Tarchitte, the agglutinating power of the organism 

 is lost in an alkaUne medium. 



Bad. paratijphosum A. These cultures were grown in acid, 

 neutral and in alkaline broth, the reactions of the media being 

 the same as with Bad. typhoswn. 



Bad. paratyphosum B. In general the differences in growth 

 and motility in acid, neutral and in alkaline broth were far less 

 marked than in the case of Bad. typhosum and Bad. paratyphosum 

 A. Both spontaneous and specific agglutination were strongest 

 in the acid medium, but the differences were less than with 

 Bad. typhosu7n or Bad. paratyphosum A. However, there is 

 some variation depending upon each stram. 



Bad. dysenteriae and Bad. coli group. On an average the speci- 

 fic serum agglutination test was sUghtly stronger in acid broth; 

 otherwise the results were almost the same for acid, neutral, 

 and alkaline broth cultures. 



In the preceding experiments the nutrient broth was prepared 

 and titrated with phenolphthalem, just before using, as I have 

 reported. The mediimi becomes more acid on standing, due to 

 the absoiption of carbon dioxide from the atmosphere. 



COMPARATIVE AGGLUTINATION TEST W^TH AG.AR CULTURE EMUL- 

 SIFIED IN SALT SOLUTION OR BROTH MEDIUM 



Bass and Watkins, Buxton and Vaugham, KoUe, Jordan, 

 Park and WilUams, Ritchie, Weil, Wretoski and other workers 

 have used salt solution, for emulsifying the agar culture for the 

 Widal test. 



Block, Grumbaum, Durham, and Ker used broth medium 

 with the agar cultures; Hiss and Zinsser used agar cultures emul- 

 sified in salt solution or broth medium. 



In my experiments, I have not found any particular difference 

 between these fluids. But agglutination is sUghtly stronger 

 with broth emulsions of Bad. typhosum, Bad. paratyphosum 

 A, Bad. dysenteriae and Bad. coli; with Bad. paratyphosum B 

 the reactions are about equal. 



