118 K. V. KossiKOV 



colour. Reseeding of such cells into fresh liquid and solid 

 media of different contents showed that the cultures could not 

 be revived. 



These data testify to the fact that different forms of 

 S. paradoxus are developed as a result of their adaptation 

 to fermentation of maltose. In one case the developed form 

 retained its acquired maltose-fermenting property not only 

 on reproduction in conditions of fermentation but also during 

 reseeding into various nutrient media. In another case, the 

 developed form retained its acquired maltose-fermenting 

 property on reproduction in conditions of fermentation, but 

 its vitality was lower. In inadequate conditions, not only does 

 it lose this property (reversion), but it dies. It is quite possible 

 that in this case alterations connected with the adaptation to 

 fermentation of maltose led to a disturbance of some physio- 

 logical processes in the cell and to disorders in cell-metabolism, 

 under the conditions of the experiment. However, this dis- 

 turbance is eliminated if a new qualitative alteration occurs 

 and the cells become capable of propagating on wort-agar, as 

 well as on media containing other sugars, the ability to fer- 

 ment maltose being retained. This statement is confirmed by 

 the above-cited three cases of the appearance of separate 

 colonies in the mass of dead cells on wort-agar. When 

 cultures selected from these 3 colonies were later reseeded, 

 they did not differ from the other 19 cultures which were 

 stable and quite viable from the very moment of development. 



Experiment 3. In this experiment, adaptation of yeasts to the 

 fermentation of simple dextrins of malt-wort was observed. 

 Experimental details have already been published (Kossikov 

 and Rayevskaya, 1956); the main results are as follows: 



S. paradoxus, previously adapted to fermentation of 

 maltose, was adapted to fermentation of simple dextrins of 

 malt-wort by means of long training on this medium without 

 reseeding. The ability to ferment simple dextrins was in- 

 creased in further reseedings of the various cultures into fresh 

 malt-wort. Some of the adapted cultures, obtained from 

 single cells, began to ferment malt-wort at the same depth as 



