600 
Studies on Enzyme Action. VII.—The Mechansm of 
Fermentation. 
By EDWARD FRANKLAND ARMSTRONG, Ph.D., D.Sc., Salters’ Company’s 
Research Fellow, Chemical Department, City and Guilds of London 
Institute, Central Technical College. 
(Communicated by Professor H. E. Armstrong, F.R.S. Received July 29, 1905.) 
[International Catalogue of Scientific Literature. 
Author’s title slip :—D. Q. R. 
Subject slips :— 
D 1800 Fermentation of carbohydrates by various yeasts. 
D 7090 Fermentation. Mechanism of alcoholic 
D 8020 Alcoholic fermentation. Mechanism of 
( 0235 Yeasts, various, action of, on carbohydrates. 
Q 1240 Fermentation of sugars by various yeasts. Mechanism of 
R 1820 Yeasts, various, action of, on carbohydrates. | 
In view of the suggestion which has been made* that the mechanism of 
fermentation is, perhaps, to be correlated with that whereby the enzymes 
effect hydrolysis, it is of importance to ascertain, if possible, the manner in 
which the activity of the various organisms giving rise to alcoholic fermenta- 
tion is dependent on or influenced by the enzymes which they contain. The 
correlation of the activity of an organism with that of its constituent 
enzymes is of special significance also on the biological side, in connection 
with the inquiry into the possibility of alterations in the activity of organisms 
being brought about by changes in their environment. 
The only systematic investigation made in this direction is that carried 
out by E. Fischer, who studied the behaviour of most of the known sugars 
towards a dozen different “pure ” yeasts, cultivated from single cells, which 
(excepting S. Maraianus and a milk sugar yeast) all contained both invertase 
and maltase. The conclusion arrived at was that only the four hexoses: 
glucose, mannose, fructose and galactose are fermentable. 
A systematic search through the literature of the subject—mostly to be 
found in bacteriological and brewing journals—shows that a large number of 
isolated observations have been made on the fermentative power of individual 
yeasts ; as a rule, however, the experiments made by various observers, if not 
incomplete, have been conducted under more or less different conditions. 
Two points stand out prominently : without exception, yeasts which ferment 
glucose also ferment fructose and mannose in all cases in which their action 
* ©Roy. Soc. Proc.,’ 1904, vol. 73, 541. 
