BY R. GHEIG SMITH. 



597 



peptone on the formation of gum is better seen on comparing the 

 amounts formed in O'Ol % and I'O % solutions; in the former the 

 ratio of gum to reducing sugars is 1 : 3 8, while in the latter it is 

 1 : 1*6. But since it is probable that the gum is formed from the 

 sugar inverted, we might calculate the ratio between the gum and 

 the sugar wholly inverted, i.e., the saccharose which has dis- 

 appeared calculated to hexose. With 0-01 % peptone this ratio 

 is 1 : 5-1, and with 1"0 % it is 1 : 2-7. So that in whatever way 

 we look at these two columns we find that an increase of peptone 

 gives an increase of gum and a relative decrease of hexoses, and 

 conversely, with decreasing amounts of nitrogenous material, there 

 is a decrease of gum and relative increase of reducing sugars. 



It is to be noted that the original composition of the culture 

 fluid as regards peptone is excellent for the purpose. The best 

 amount would probably be 0-3 or 0-4 %. It was also found inciden- 

 tally that 10 % of saccharose is about the optimum quantity. 

 With 20 % (and even in the presence of 1 % peptone) the fermen- 

 tation was far from complete. 



The Action upon other Sugars. 



In testing the action of the bacillus upon other sugars, solutions 

 similar to those already employed, but containing other sugars in 

 place of saccharose, were used. Dextrose was first tested, and 

 media containing commercial starch glucose were infected and 

 cultivated at 37° and 22'' respectively. The organisms grew well 

 in the media and produced a turbidity and a flocculent precijDitate. 

 The dextrose was estimated from time to time, and the followinir 

 numbers were obtained : — 



