80 B. BRADLEY. 



method, and the bio-chemical method. Without discussing 

 the value or otherwise of the first procedure, I intend to 

 confine myself here to the consideration of the latter. 



The history of the use of the changes produced by 

 organisms on various chemical substances is a long one, 

 and I do not pretend to give it more than a brief consider- 

 ation, but before proceeding to my own work I wish to 

 refer to the finding by certain observers who have specially 

 entered into the matter. 



Silberschmidt (1895) (37) noted that b. hog cholera fer- 

 mented glucose with the formation of acid and gas and 

 produced no indol. 



Widal and Nobencourt (1897) (15) describe the organism 

 they isolated from a thyroid abscess as a gram negative 

 bacillus, non-gelatin liquefier, pathogenic for guinea pigs 

 and mice. On glucose and mannit acid and gas were pro- 

 duced, lactose and saccharose were unaffected. 



Thomassen's (1897) (36) nephritis organism was almost 

 certainly Gaertner type to judge by the agglutination 

 results. He describes it as an actively motile organism 

 resembling b. typhosus, not liquefying gelatin, growing in 

 an " invisible " manner on potato. Milk was not coagulated 

 up to three weeks. Glucose was fermented, acid and slight 

 gas being produced — no action occurred on lactose. It 

 produced a slight trace of indol and was very virulent. 



Gwyn (1898) {16) describes in some detail the organism he 

 recovered from the blood of a case clinically typhoid. This 

 is the first ''paratyphoid" on record. It was a gram 

 negative flagellated organism showing on gelatin "blue" 

 colonies. It produced acid and gas on glucose, mannit and 

 levulose (slight action on saccharose). 1 No action occurred 

 on lactose. Milk showed "cameleonage," being first acid 

 then neutral within ten days. 



1 This is not confirmed by later observers, and was probably due to 

 traces of glucose in the saccharose used. 



