332 Mr. F. W. Twort. Fermentation of Glucosides by [Mar. 7, 



The last four of these sub-groups correspond to the four groups of 

 MacConkey. 



On looking at the table it is apparent — 



1. That there is comparatively little difference between the fermenting 

 capabilities of many of the lactose fermenters. 



2. That two micro-organisms of a sub-group may differ in their ability to 

 ferment glucosides, whereas micro-organisms in different sub-groups may 

 present the same fermentative changes when tested on glucosides. 



It will also be noted that the chief fermentations occur in the four sub- 

 groups of lactose fermenters, but whereas the members of the true coli 

 group give practically identical results when tested on glucosides, the results 

 with members of the Friedlander group show greater variations, the chief of 

 which is the inability of B. neopolitanus and Bacillus ISTo. 41 to ferment 

 salicin, arbutin, and syringin, which glucosides are easily fermented by 

 B. friedlander. It must also be pointed out that the fermentation of many 

 glucosides is neither marked nor constant. 



Taking the individual glucosides in the table and reading from left to 

 right, the following are the chief general characteristics of the fermenta- 

 tions : — 



Gas production very variable, often marked. Acid 



production seldom present, never marked. 

 Gas and acid formation never very marked. 

 Acid and gas extremely variable, often marked. 

 Usually show very distinct fermentation, both acid and 

 gas being frequently very marked, occasionally slight. 

 Gas sometimes marked, acid always slight. 

 Gas never excessive, acid production very variable. 



Brown euonymin. 



Green euonymin. 

 Iridin and senegin. 

 Coniferin, arbutin, 

 salicin, syringin. 

 Quillajinic acid. 

 Populin. 



Camellin, globus 



larin, cerberid, I Gas production always slight, acid never very pro- 

 periplocin, ca- nounced. 

 thartinic acid. -* 



Amygdalin. 



Sapotoxin. 



Saponin. 



Bryonin and con- 

 vallamarin. 



Gas never formed, acid production variable and some- 

 times marked, especially with members of Capsulatus 

 and Friedlander sub-groups. 



Gas production always slight, acid variable, but most 

 pronounced, with Capsulatus and Friedlander sub- 

 groups. 



Gas very rarely present, acid usually slight. 



Acid and gas never very pronounced and very incon- 

 stant. 



