1908. | The Alcoholic Ferment of Yeust-jwee. 305 
Amount of free phosphate present. Amount of 
; hexosephosphate 
Solution. hydrolysed by 
Before incubation. | After incubation. enzyme. 
1. Hexosephosphate equivalent to 0:0 0 -0089 
0 1626 gramme Mg,P,0, 
| 2. 0°75 gramme residue + water ...... 0-0 0 -0166 
| 3. 0°75 gramme residue + hexosephos- | 0°0 0 1068 0 0813 
phate equivalent to 0:°1626 
gramme Mg,P.O, 
4, 0°75 gramme residue + hexosephos- 0 1626 0 1884. 0 0003 
phate as above, +sodium phos- 
phate equivalent to 0-°1626 
gramme Mg,P.O0, 
decomposition of the hexosephosphate is almost completely arrested by the 
presence of an equivalent of free phosphate. 
The amount of phosphate actually produced in solution 3 from all sources 
is 01068 gramme Moeg2P20;, which corresponds to an evolution of about 
22 cc. of carbon dioxide, and this in spite of the fact that the phosphate has 
been allowed to accumulate. The amount which would be evolved in 
presence of glucose and coferment would naturally exceed this, owing to the 
continued reconversion of the phosphate into hexosephosphate. 
This experiment also shows that the ferment which brings about the 
hydrolysis of the hexosephosphate is present in the residue obtained by 
filtering yeast-juice through a Martin-filter, and does not require a dialysable 
coferment. 
The second difficulty arises from the fact that when yeast-juice or a 
mixture of ferment and coferment is employed, a certain amount of 
fermentation always occurs, even in the absence of added sugar. This is due 
to sugar formed in the liquid, in part by the hydrolysis of glycogen and 
dextrins and in part by the hydrolysis of the hexosephosphate itself, which yields 
a fermentable sugar as one of its products. The practical result is that if an 
actual comparison be instituted between the production of phosphate in 
the absence of added glucose and the evolution of carbon dioxide in the 
presence of glucose, it will be necessary to take the sum of the carbon dioxide 
actually evolved and the carbon dioxide equivalent of the phosphate 
produced in the absence of added glucose, and this will always be found to be 
less than the volume of carbon dioxide observed in the presence of glucose. 
The result of such a comparison is shown in the two following experiments. 
A mixture was made of yeast-juice with a solution containing a suitable 
amount of sodium phosphate and just sufficient glucose to bring about the 
conversion of the greater portion of the phosphate into hexosephosphate, this 
