Xll BY .7. THOMSON, M.K. 



and a form of fermentation is set up. The yeast, proliferating, 

 attacks the ghiten, starch and sugar of the flour ; the later 

 passes into alcohol and the dough swells up — "rises" — and is 

 distended with innumerable air spaces from the evolution of 

 carbonic acid. The subsequent baking still further inflates the 

 air cavities, but the carbonic acid is destroyed, the alcohol is 

 driven off, and the ferment killed. 



In Brewing, a similar thing — vinous fermentation— occurs. 

 The sugar to be subsequently acted upon is derived from barley ; 

 first, during the stage of malting, or germinating, when the 

 starchy particles undergo alteration ; and second, during the 

 process of mashing, when a nitrogenous and unorganised 

 ferment— diastase — changes the modified starch of the malt into 

 malt-sugar (maltose) and dextrine. After boiling with hops and 

 And other processes, yeast is added and fermentation begins. 

 The surface of the liquid is covered with a brownish cream 

 which rapidly increases in volume by the speedy proliferation of 

 the yeast cells ; the cream becomes enormously frothy and 

 "rocky" by the abundantly escaping carbonic gas which 

 accumulates densely on the surface of the fermenting liquid ; 

 the temperature of the liquid rises ; and its specific gravity falls 

 owing to the presence of alcohol. 



Think, just for a moment, what a terrific influence in the 

 ■wide world this tiny yeast cell wields What an enormous, 

 what a vast-spread industry depends upon its little growth. 

 What a mint of money ; millions, countless millions, sums far 

 beyond our reckoning or our ken are backing its behaviour. No 

 wonder it has to be kept healthy ; no wonder its cultivations 

 have to be pure ; no wonder a Pasteur and a Hansen devoted 

 their talents and spent many of the best years of their lives to 

 the study of the yeast plant and the role it plays in fermentation. 



Having referred so frequently and so recently to alcohol, it 

 may astonish you to learn that it is only at the extremes of 

 Creation that any love or liking for this fluid — beverage — poison 

 —call it what you will — is discoverable. Man, at the one 

 extreme may be described as an alcohol drinking animal ; 

 certainly it is for him, and him only, that that industry and 

 that wealth just referred to, has been established and has been 

 invested. No other living thing that is in the hea\en above 

 or that is in the earth beneath or that is in the water under the 

 €arth is alcoholicly inclined — save one. At the other extreme, 

 at the lowest rung of life's ladder, we find the yiijcodenua Aceti, 

 an organism which simply revels in wine, lives and multiplies 



