806 



THE PERMANENCY OF THE CHARACTERS OF THE 

 BACTERIA OF THE BAC. C0Z/-GROUP. 



By R. Greig-Smith, D.Sc, Macleay Bacteriologist to the 



Society. 



In a paper upon the Bacterial Flora of Rachitic Stools,* a 

 table was given showing the cultural characters of certain Gram- 

 negative bacteria of the Sac. coli-gronp. These diflfered more or 

 less from one another and, from the gradual variations, the- 

 opinion was expressed that further cultivation might bring about 

 such alterations as to reduce the number of races. 



Certain of the bacteria were cultivated upon artificial media- 

 for over seven months, and occasionally examined during the 

 period of cultivation. Many of the characters were found to be 

 permanent, while a few proved to have been only temporary. 

 The alterations applied to what may be called the negative 

 characters, and it was evident that with some of the bacteria the 

 absence of fermentative activity was only transient. 



A reference to the table in the former paper(p.38), will assist 

 in explaining the relation of the bacteria with the restored 

 characters, to the others. Twelve bacteiia were under obser- 

 vation; these were the first twelve that were obtained in the 

 former research. 



The characters of Bj, B,,, B13 and B^g were permanent, and 

 the clianges in the others were as follows : — 



Motility: B^ and Bj2 became motile. 



Growth on gelatin: B._., B^ and B^j finally grew as a Hut 

 expansion. 



Neutral-red: Bj g developed a fluorescence under anaerobic con- 

 ditions. 



Dextrose and Mannit: The characters were permanent. 



*A'nUa, p.36. 



