1906.] The Alcoholic Ferment of Yeast-juice. 373 



residue and glucose, care being taken to keep the concentration of glucose the 

 same throughout. 



Material digested. 



Time ot digestion. 



Volume of 

 filtrate taken. 



Fermentation 

 produced. 









days. 



c.c. 



c.c. 



1. 



a. 









20 



168 -5 





b. 



9 



20 







2. 



a. 









16 



364 3 





b. 





2 



16 



2-6 





c. 





4 



16 









a. 









15 



62 -9 





b. 





1 



15 



2 -1 





e. 





2 



15 









d. 





4 



15 









e. 









15 



62 -9 









1 



15 



15 "6 











2 



15 



4-5 





h. 





4 



15 



8 3 



In two cases in which a negative result was obtained (15 and 2c) an equal 

 volume of the same fresh boiled juice was added and in both cases a vigorous 

 fermentation was produced, thus proving that the autolysed juice had not 

 exerted any specific detrimental effect on the ferment : — 



Fresh boiled juice added. Carbon dioxide evolved. 



1. 1 20 c.c. 112 c.c. 



2. c 16 „ 297 „ 



It appears from this that the coferment disappears from the juice less 

 rapidly in the presence of glucose than in its absence. In yeast-juice to 

 which no addition of glucose has been made the coferment usually disappears 

 at 26° in about 48 hours ; in the presence of 10 per cent, of glucose coferment 

 was still present at the end of four days, although only in a small amount. 

 (The observation that the fermentation after four days' incubation is some- 

 what greater than that given after two days is probably to be explained by 

 the presence of a greater amount of phosphate in the juice which had been 

 digested for the longer period.) 



4. Soluble Phosphates do not Haider the Inactive Residue Capable of Fermenting 



Glucose. 



In view of the fact that soluble phosphates, as described in the previous 

 communication, exert a remarkable effect on the fermentation of glucose by 

 yeast-juice, experiments were made to ascertain whether the addition of a 

 soluble phosphate to a solution of the inactive residue in glucose is sufficient 



