1908.] The Alcoholic Ferment of Yeast-jucce. 309: 
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more different unstable associations with the fermenting complex. One of’ 
these, formed with low concentrations of the phosphate, has the composition 
most favourable for the decomposition of sugar, whilst the others, formed 
with high concentrations of phosphate, contain more of the latter, probably 
associated in such a way with the fermenting complex as to render the: 
latter partially or wholly incapable of effecting the decomposition of the 
sugar molecule. As the fermentation proceeds slowly in the presence of. 
excess of phosphate, the concentration of the latter 1s reduced by conversion: 
into hexosephosphate, and a redistribution of phosphate occurs, resulting 
in the gradual change of the less active into the more active association 
of phosphate with fermenting complex, and a consequent rise in the rate of | 
fermentation. 
In those cases in which the maximum rate corresponding to the optimum 
concentration of phosphate is never attained, some secondary cause may be - 
supposed to intervene, such as a permanent change in a portion of the 
fermenting complex, accumulation of the products of the reaction, etc. 
Experiments on this point are being carried out by varying independently — 
the concentration of the ferment, the coferment, the phosphate, and the. 
hexosephosphate. 3 * 
In agreement with these conclusions it is found that a high rate of evolution | 
of carbon dioxide can be maintained for a considerable period by the gradual 
addition of phosphate in such a way that the concentration of free phosphate - 
remains approximately at the optimum value. This may be effected by’ 
