?34 NON-SACCHAROMYCETES OR DOUBTFUL YEASTS 



the shape of their cells. One of them produces filaments resembling 

 the mycelium of Monilia. Finally they may be distinguished by 

 their macroscopic appearance in solid media (giant colonies, streak 

 cultures, etc.). In solutions of dextrose and levulose, both species 

 form a scum which is filled with bubbles of carbon dioxide, the cells 

 fall to the bottom of the culture flask and induce a very active fer- 

 mentation. Both species, like Willia anomala, form ethyl ether. 

 The optimum temperature for budding in these species is 32-41 C. 

 These yeasts easily ferment dextrose and levulose but scarcely act on 

 maltose and dextrine, and not at all on lactose, saccharose, raffinose, 

 and inuline. In dextrose solutions, about 37 per cent of alcohol is 

 formed by volume. Both species are able to utilize lactic acid as a 

 food; they endure up to 5 per cent of this acid. They are also able 

 to withstand quite large amounts of alcohol (11 per cent). The 

 alcohol is rather rapidly oxidized to CO 2 and H 2 O. 



MYCODERMA CUCUMERINA. Aderhold 



Discovered by Aderhold, 1 this species lives in beer and wine and 

 brings about certain undesirable changes with an acrid taste. It 

 oxidizes alcohol and lactic acid and produces from them volatile acids; 

 however, it does not grow in more than 1 per cent of alcohol. This 

 species may also transform alcohol into succinic acid, malic acid and 

 tartaric acid. 



MYCODERMA VALIDA. Leberle-Will 2 



The cells are cylindrical or oval (6-8 /z long and 2-4 /* wide). 

 The temperature limits for growth are 1-45 C., optimum 20-25 C. 

 This yeast assimilates dextrose and levulose and oxidizes ethyl alcohol 

 very energetically. It assimilates the organic acids very easily, es- 

 pecially lactic acid. 



MYCODERMA GALLICA. Lerberle-Will 3 



The cells of this yeast are either oval or cylindrical (7-10 ju long 

 and 2-3 /z wide). The temperature limits for growth are 7 and 30 C. 

 The optimum is 20-25 C. This species assimilates dextrose and levu- 

 lose. It oxidizes alcohol quite energetically and easily assimilates the 

 organic acids. 



1 Aderhold, R. Arbeiten der Botan. Abteilung d. Versuchsstation. d. pomolog. 

 Inst. zu Proskau. Cent. Bakt. 5, 1899. 



2 Will, H. Beitrage zur Kenntniss der Gattung Mycoderma nach Unter- 

 suchungen von Hans Leberle. Cent. Bakt. 28, 1910. 



3 Will, H. See reference under Mycoderma valida. 



