The Alcohol-producing Enzyme of Yeast. 
BY 
J. REYNOLDS GREEN, Sc.D., F.R.S., 
Professor of Botany to the Pharmaceutical Society of Great Britain . 
I N a paper published in this Journal last year 1 , I gave an 
account of some researches which I carried out with the 
object of confirming the discovery which had been announced 
some few months earlier by Dr. E. Buchner, that the alcoholic 
fermentation of sugar is effected by the activity of an enzyme 
or soluble ferment which, by appropriate means, can be 
extracted from the yeast-cell. 
My experiments were made upon both high and low 
fermentation yeasts, procured without any special precaution 
from breweries actually at work, so that my inquiry might 
show whether in ordinary brewing operations the fermentation 
of the wort is due to an enzyme. 
The yeasts I used were taken after the greatest activity of 
fermentation had subsided, and were kept in the laboratory 
for a day or two before using, so that they may be spoken 
of as being in the resting condition. 
I followed closely the method of preparation described 
as his own by Dr. Buchner. Though I succeeded in pre- 
1 Annals of Botany, XI, No. XLIV, Dec. 1897, p. 555. 
[Annals of Botany, Vol. XII. No. XL VIII. December, 1898.] 
