114 K. V. KossiKOV 



fermented maltose during a period of 30 days on a medium 

 containing maltose. The experiment was carried out in flasks 

 fitted with Maysle gas-seals, each flask containing 50 ml. of 

 medium. One-half of each type of culture was seeded on a 

 medium containing 2 per cent maltose, • 75 per cent glucose 

 and • 3 per cent autolysed yeast extract ; and the other half 

 was seeded on beer-wort (saccharimeter: 14°). Maltose- 

 fermenting cultures of S. ellipsoideus 169 were seeded on the 

 same media, as a control. Sugar-fermentation was registered 

 by a decrease in the weight of the flasks due to evolution of 

 carbon dioxide. During the first 3-4 days there was a slight 

 decrease in the weight of all the experimental flasks, due in 

 the one case to fermentation of glucose and in the other to 

 fermentation of the beer- wort monosaccharides. At the end of 

 this period (3-4 days), fermentation ceased in the experi- 

 mental flasks due to the inability of cells of S. glohosus to 

 ferment the maltose in the medium; while in the control 

 flasks, fermentation proceeded (as a one-peak curve) and all 

 sugars, including maltose, were largely fermented at the end 

 of 4-5 days. It was assumed that, in the experimental flasks, 

 in the case of the development of cells capable of fermenting 

 maltose, secondary fermentation would arise resulting from 

 fermentation of maltose. 



The flasks were weighed daily for a period of 107 days; and 

 it was found that in this time fermentation began in two 

 cases in the experimental flasks — in the one case in the flask 

 seeded with S. glohosus 72/349, and in the other in the flask 

 seeded with the hybrid culture 217/3. Reseeding of cells from 

 both these flasks, into fresh beer- wort medium (containing 

 maltose), showed that in both cases cells had become adapted 

 to fermentation of maltose, and this maltose-fermenting 

 ability was retained even during numerous reseeding into 

 wort-agar. 



Experiment 2. In this case, the solid medium, wort-agar, was 

 used for the adaptation of yeast to fermentation of maltose. 

 The medium was poured into 4 shallow glass plates, of a 

 capacity of 1000 ml., each plate containing 200 ml. of medium 



