VARIATIONS IN TYPHOID BACILLI 



311 



Results are recorded after two hours incubation at 37°C. and stand- 

 ing in an ice chest over night. Hereafter we shall use the following 

 abbreviations : 



Cohen S = Cohen strain cultivated in serum broth 

 Cohen B = Cohen strain cultivated in broth (control) 

 C-188 B = C-188 strain cultivated in broth (control). 

 Tests done in Rawlings serum after absorption of this serum in dilu- 

 tion of 1:100 at 37°C. for three hours with the "serum" and the 

 "broth" strains respectively: 



(a) 



After absorption of C-188 serum in dilution of 1 : 100 at 37°C. for three hours. 



