576 Drs. T. A. Henry and 8. J. M. Auld. [July 22, 
trace of this acid could be detected. The dextrose first formed in this 
action is changed by the zymase of the yeast forming alcohol and carbon 
dioxide. 
Mandelonitrile Glucoside——Fischer has shown that this glucoside is readily 
hydrolysed by emulsin. It is also hydrolysed by yeast; thus, when yeast 
was added to a solution of 0°5 gramme of the glucoside dissolved in 10 cc. of. 
water and the mixture kept at 40°, the odour of benzaldehyde was observed 
after 36 hours, and after 72 hours +40 per cent. of the glucoside present had 
been decomposed. ‘The dextrose first formed was decomposed by the zymase 
of the yeast. 
Other Glucosides.—In the same way it was found that arbutin and phaseo- 
lunatin were decomposed by yeast, whilst quercitrin, digitalin and sinalbin were 

unattacked by it. 
It seemed possible that this action of yeast on glucosides might be due to 
the direct fermentation of the sugar residues present in these substances by 
the zymase contained in the yeast or its preparations, with the result that 
the molecule underwent total disruption, the products other than sugars being 
non-fermentable and, therefore, remaining intact. This explanation of the 
action is, however, not permissible in view of the fact that the action of yeast — 
is restricted to certain types of giucosides, and that it does not decompose 
digitalin or quercitrin, although these contain residues of the fermentable 
sugars, digitalose and rhamnose respectively. Moreover, Fischer has asserted 
that disaccharides are never fermented directly by yeast, and that the latter 
only attacks hexoses produced by the preliminary decomposition of di- 
saccharides by hydrolytic enzymes such as invertase, maltase and lactase, and 
bearing in mind the analogy in constitution between glucosides and the 
disaccharides established by Fischer, it is probable that the same rule holds 
good with regard to glucosides. 
Fractionation of Yeast Juice by Heat Coagulation. 
Wroblewski* has shown that when yeast juice is heated, coagulations of 
proteid matters occur at certain definite temperatures, and that in particular 
the filtrate from the coagulate produced at 41° is practically free from zymase.f 
Wroblewski’s experiments were repeated, small tubes containing the yeast: 
juice being heated gradually to various temperatures between 40° and 70°. 
The coagulates obtained at these various temperatures were filtered off and 
the activity of the filtrate in each case towards amygdalin and dextrose was 
determined. The principal coagulates were found to be produced at 48°, 55°, 
* ‘Berichte,’ 1898, vol. 31, p. 3218, and ‘ Journ. prakt. Chem.,’ 1901, vol. 64, p. 1. 
+ Compare Buchner, ‘ Berichte,’ 1899, vol. 32, p. 2086. 
