557 
Alcoholic Enzyme in Yeast. 
temperature of the laboratory or for two days at o° C. The 
inactive liquid which gave a bulky coagulum at 45°-5o° C. 
when gradually heated, while in possession of its powers, 
seems to lose the power of forming the coagulum as its 
fermentative property disappears. Buchner suggests that the 
supposed enzyme is proteid in character, and is digested 
rapidly in the liquid, with the other proteids it contains, under 
the influence of peptic enzymes extracted from the cells. 
Buchner says further that if the Yeast be very carefully 
dried, it can be heated for six hours to a temperature of ioo° C. 
without destroying the power of the Yeast to induce fer- 
mentation. This temperature is sufficient to kill the cells, 
but, according to the author, is not high enough to destroy 
the enzyme they contain. Hence a fermentation can be 
obtained similar to that set up by his Yeast-extract. 
The appearance of these researches excited a good deal 
of interest, especially among physiologists and chemists, the 
more so as the Yeast-plant has always been the chief 
support of the vitalistic theory of fermentation put forward 
by Pasteur. It is only natural that researches have been 
undertaken by many workers with the view of confirming 
or disproving Buchner’s statements. I have for several 
months been at work upon the subject, and have embodied 
my experiences in the present paper. 
On reading Buchner’s account of his experiments it appears 
that he lays great stress on the evolution of carbon dioxide 
from the mixtures of his extract with the various solutions 
of sugar which he used. To him such an evolution of gas 
was evidence of fermentation, and his deduction was that 
an enzyme was at work in his liquids. There are, however, 
two other points to which attention may fairly be called in 
conducting the experiments. The sugar-solution should 
gradually become of a less specific gravity as the fermenta- 
tion proceeds ; conditions being constant, this diminution of 
specific gravity should be regular as well as progressive. 
Also there should be a gradual and continuous formation 
of alcohol in the liquid as the fermentation proceeds. If 
P p 2 
