ALCOHOLIC FERMENTS. 181 



SACCHAROMYCES ANOMALUS. HANSEN. 



(Figs. 31 and 47). 



This very curious species was found by Hansen in an 

 impure brewery yeast from Bavaria. It gives a rapid and 

 vigorous fermentation in wort, and even at the beginning of 

 the fermentation develops a dull grey film. During fermen- 

 tation the liquid acquires an ethereal, fruity odour. 



this is made by kneading together flour, bran, and water, and allowing 

 the mass to undergo spontaneous fermentation. It contains bacteria in 

 large numbers, and also yeast-like cells, and amongst the latter alcoholic 

 ferments. Very opposite views have, however, been expressed with 

 regard to the importance of these different organisms in the fermentation 

 of black bread. 



According to Chicandart (1883) and Marcano the active ferment is a 

 bacterium. Boutroux attributed the fermentation to the activity of both 

 bacteria and budding fungi ; later he regarded alcoholic yeast as the 

 chief cause. Laurent regarded the so-called Bacillus panificans as the 

 main cause of the fermentation of bread. Dilnnenberyei-' s investigations 

 led to the conclusion that the budding fungi must be looked upon as the 

 only essential organisms of fermentation in bread. The rising of the 

 dough is accordingly caused in the first place by the carbonic acid 

 liberated by the alcoholic fermentation ; further by the expansion of 

 the air and the vapourisation of the alcohol, water, and volatile fatty 

 acids formed by the bacteria. Peters found four different budding fungi 

 in leaven, and one of these has been identified with Saccha?'omyces minor 

 Engel. The second is of about the same size as Saccharomyces minor ; 

 the cells are egg-shaped, and in nutrient liquids develop to moderately 

 large, many-branched colonies ; it yields spores abundantly. In addition 

 to the above, a species of Mycoderma and a species related to Saccharo- 

 myces cerevisice were also found. Peters describes several species of 

 bacteria occurring in leaven, but none of them has all the properties of 

 Laurent's Bacillus panificans; on the contrary, these properties were 

 found divided amongst various bacteria. Laurent, therefore, was pro- 

 bably dealing with impure cultivations. These bacteria gave no alcoholic 

 fermentation, and no appreciable evolution of gas in sterilised dough. 



The above experiments constitute a good preliminary to the decisive 

 experiments on the cause and action of the rising of dough. 



The diseases of black bread which have been investigated by 

 Ujfelmann, Kretschmer, and Niemitowicz, e.y., vigorous growth of 

 mould, sliminess caused by an exuberant growth of bacteria, may no 

 doubt be partly attributed to impure leaven, in which the most various 

 organisms will thrive. 



