STUDIES UPON AGGLUTINATION 55 



ciiiite as satisfactory for agar or broth cultures, especially as it 

 is to be found in most laboratories. 



There were no indications that the use of tap water or distilled 

 water was better than salt solution, when we used broth cultures. 



COMPARATIVE AGGLUTINATION TESTS WITH VARIOUS CULTURE 



MEDIA (table 8) 



In conducting agglutination tests of the colon-t>^3hoid group 

 various kinds of culture media have been used. The cultures 

 were grown at 37°C. for 24 hours in neutral broth, one per cent 

 glucose broth, one per cent pepton water and on agar, the agar 

 cultures being emulsified with salt solution. 



Bad. tijphosum. Grown in plain broth, glucose broth, pep- 

 ton water and on agar, it showed the strongest agglutination with 

 specific serum in the first named medium, becoming weaker in 

 each of the others in the order given ; the reaction was very weak 

 with agar cultures. Dreyer claims that glucose broth cultures 

 have a tendency to spontaneous agglutination, but my results 

 hi using glucose broth were quite irregular; spontaneous agglu- 

 tination occurred m some cases, while in others there was no 

 spontaneous agglutination, but there was generally negative or 

 weak spontaneous agglutination with both spontaneous and 

 non-spontaneous agglutinating types. 



.\s compared with cultures in plain broth those grown in 

 glucose broth showed very irregular and weak motility. Forma- 

 hnized serum showed stronger agglutination than plain serum; 

 especiallj^ marked was the difference with glucose broth. With 

 plain broth or pepton water or agar cultures, the difference was 

 a great deal less marked. 



Bad. paratyphosum A. Cultures grown in glucose broth showed 

 weak motility, many strains agglutinating spontaneously, even 

 though non-spontaneous agglutinatmg bacilli were used. Form- 

 alin does not prevent this agglutination. 



In specific agglutination tests glucose broth cultures showed 

 considerable reaction, even more than with pepton water or 

 agar cultures. However, these results are due to the spontaneous 

 agglutination in the glucose broth. It is evident, that this 



