1905.] 



The Alcoholic Ferment of Yeast-Juice. 



415 



times as high as the constant rate attained after the evolution of the carbon 

 dioxide equivalent to the phosphate present. 



Table VI. — Equivalence of Extra Carbon Dioxide Evolved during the 

 Initial Period, and Phosphate added. 



Experi- 

 ments. 



Grammes of carbon dioxide. 



Experi- 

 ments. 



Grammes of carbon dioxide. 



Column I — 

 Observed. 



Column II — 

 Calculated 

 from phosphate. 



Column I — 

 Observed. 



Column II — 

 Calculated 

 from phosphate. 



1 



090 



1 



0-086 



8 



196 



197 



2 



054 



0-055 



9 



0-066 



0-065 



3 



0-058 



051 



10 



0-057 



0-061 



4 



0-060 



0-049 



11 



0-056 



0-061 



5 



0-106 



112 



12 



0-059 



061 



6 



0-103 



0-101 



13 



0-068 



0-070 



7 



0-113 



-112 



14 



071 



0-070 



At the commencement of the period when sodium or potassium phosphate 

 solution has been added, the rate only gradually acquires its maximum value 

 and sometimes it only attains this maximum after a considerable interval. 



This phenomenon is occasionally observed in the fermentation produced by 

 yeast-juice without the addition of phosphate, and also sometimes occurs, but 

 to a much smaller extent, when boiled juice is added. It is well shown in 

 Curve B, fig. 3, which represents the fermentation produced by 25 c.c. yeast- 

 juice + 25 c.c. of a - 06 molar solution of sodium phosphate +5 grammes 

 glucose + toluene. The cause of this period of induction has not yet been 

 ascertained. 



7. Limit of the Action of Phosphate. 



If the fermentation in presence of phosphate be allowed to continue until 

 the steady rate is attained and a second quantity of phosphate be then added, 

 a second period of rapid evolution of carbon dioxide sets in and proceeds in a 

 similar manner to the first. This is shown in Curves B and C, fig. 3, which repre- 

 sent the effect of the successive addition of two quantities of 5 c.c. of 03 molar 

 sodium phosphate to 25 c.c. yeast-juice + 20 c.c. water, in presence of 10 per 

 cent, glucose. Curve A represents the fermentation in absence of added 

 phosphate. The phosphate solution employed was a mixture of five 

 molecules of NaH^PO* with one molecule of Na^HPOi and no correction 

 for combined carbon dioxide was required. The extra amount of carbon 

 dioxide evolved after each addition is the same, and is equivalent, as 

 vol. lxxvii. — B. 2 h 



