1910.] llie Alcoholic Ferment of Yeast-juice. 329 



the identity of the hexosephosphates from these three sugars may possibly 

 be explained in either of two ways. In the first place it is to be noted that 

 these three sugars have a common enolic form, and the hexosephosphate 

 may he a derivative of this. In the second place, it is possible that the two 

 molecules of sugar which are involved in the reaction, of which the equation 

 is given above, may be decomposed into smaller groups, and that the hexose- 

 phosphate may be formed by a synthesis from these. As the formation 

 of the hexosephosphate is invariably accompanied by that of an equivalent 

 amount of carbon dioxide and alcohol, the second explanation appears the 

 more probable, as it provides a source for the simultaneous production of 

 these substances. 



According to this view two molecules of the hexose, or possibly of the 

 enolic form, are each decomposed primarily into two groups. Of the four 

 groups thus produced, two go to form alcohol and carbon dioxide, and the 

 other two are synthesised to a new chain of six carbon atoms, which forms 

 the carbohydrate residue of the hexosephosphate. The introduction of the 

 phosphoric acid groups may possibly occur before the rupture of the original 

 molecules, and may even be the determining factor of this rupture, or, again, 

 this introduction may take place during or after the formation of tlie new 

 carbon chain. Sufficient information is not yet available for the exact 

 formulation of a scheme for this reaction. Such a scheme, it may be noted, 

 would not necessarily be inconsistent with the views of Wohl and Buchner 

 as to the way in which the carbon chain of a hexose is broken in the process 

 of fermentation, but would interpret differently the subsequent changes 

 which are undergone by the simpler groups whicli are the result of this 

 rupture. 



It may, however, be })ointed out tliat if the hexosephosphate be a derivative 

 of the enolic form common to mannose, glucose, and fructose, the compound 

 derived from galactose should be different. If, on the other liand, the 

 hexosephosphate be derived from fractions of two hexose groups, the galactose 

 compound might, or-might not, be different from that derived from the other 

 hexoses. The enolic form of galactose differs from that of mannose, glucose, 

 and fructose, in the symmetry of its 7-carbon atom, and the production of a 

 hexosephosphate different from, or identical with, that derived from glucose, 

 would depend on the preservation or destruction of the symmetry of this 

 cai'bon atom in the reaction. It appears, therefore, that a study of the 

 behaviour of galactose towards phosphate in the presence of the yeast enzymes 

 maj' have an important bearing on the question, and experiments on this 

 subject are now in progress. 



