VARIATIONS IN TYPHOID BACILLI 289 



As to the results of Penfold and Reiner-Miiller, our results 

 agree pretty definitely with those reported by these workers. 



No strains corresponding to those described by Bull and 

 Pritchett were met with by us and we were able to find no similar 

 ones described in the literature. 



We have confirmed the observations of Krumwiede, Kohn 

 and Valentine, and in addition have shown in this work, as well 

 as in a previous publication with Dr. Teague, that rapid xylose 

 fermenters can be produced from slow fermenters with consider- 

 able ease. 



Although in almost every respect our work corresponds with 

 that of Winslow, Kligler and Rothberg, they do not entirely 

 correspond with the results of these workers in regard to the 

 action of the typhoid bacillus upon arabinose. Subcultures 

 that ferment arabinose rapidly still retain this characteristic 

 after having been kept on plain nutrient agar for one or two 

 months. 



The enzyme produced by a typhoid bacillus from one of the 

 sugars, xylose, arabinose, or dulcitol, may be greatly increased 

 without affecting the production of ferments for the other two 

 sugars. In anaerobic cultures of typhoid bacilli the lack of 

 oxygen supply causes a partial inhibition of growth. 



DAUGHTER COLONIES^ 



Reiner Miiller (1908, 1911) first showed that Bad. typhosum produced 

 daughter colonies on rhamnose agar. He examined a large number of 

 cultures in this regard and foimd that they all gave rise to daughter 

 colonies and further that Bad. typhosum produced daughter colonies in 

 eight days on agar containing as little as 0.025 per cent of rhamnose 

 and in fourteen days on agar containing only 0.01 per cent. He sug- 

 gests that the development of daughter colonies on rhamnose agar 

 might be utilized in the identification of Bad. typhosum; the results 



2 The term "daughter colony" is used throughout as signifying the type of 

 secondary colonies arising spontaneously within the substance of the parent col- 

 ony. The formation of these daughter colonies seems to signify that certain 

 individual cells within the colony acquire the property of utilizing the sugar and 

 therefore growing with much greater speed than the remaining bacteria making 

 up the mother colony. 



