322 NON-SACCHARQMYCETES OR DOUBTFUL YEASTS 



It ferments dextrose and in a 10 per cent solution of this sugar pro- 

 duces 4.5 per cent of alcohol by volume. It inverts saccharose and 

 ferments maltose. It has no action on lactose. 



SACCHAROMYCES JAPONICUS. Yabe 1 



This yeast was isolated from some swampy fields in Japan on rice 

 leaves. It is frequently encountered as is S. keiskenna in dust of the 

 air in Japan. The cells are elliptical and slightly rounded. In Pas- 

 teur's medium, they measure 6 x 3jii; in meat bouillon, 9.2 X oju, 

 sometimes reaching 10.3 X 6.1/z. The budding is accomplished by a 

 special method. The cells send out a long tubule about twice as 

 long as the cell at the end of which there develops an enlargement 

 constituting the bud. In certain cases, especially in peptone broth, 

 this filament branches in place of budding and gives mycelial forma- 

 tions. This produces a red scum on liquids which falls to the bottom 

 of the flask when disturbed. Stab cultures on carbohydrate gelatin 

 after a few weeks show along the line of inoculation a feeble trace 

 of growth. On the surface, on the contrary, a reddish pellicle is formed 

 which develops progressively and liquefies the gelatin. This yeast is 

 essentially aerobic producing no fermentation. The red pigment ap- 

 pears only in contact with air and is especially formed in cultures on 

 potato. Saccharose and dextrose are good foods for this yeast, better 

 than lactose. Alcohol to 3 per cent retards development; 7 per cent 

 of alcohol prevents it. The cells die in 5 minutes at 45 C. 



SACCHAROMYCES KEISKEANA. Yabe 



This yeast was found by Yabe 2 along with the preceding one. Its 

 cells are of a pale reddish color and are always spherical (5.1ju in 

 diameter). Under good conditions of nutrition they may reach 9/x. 

 The cells grow by a budding analogous to that of bottom beer yeasts. 

 No mycelial formation exists. In stab cultures on gelatin, this yeast 

 only produces along its line of inoculation a small number of cells 

 which remain colorless ; with the exception of those on the surface, 

 no liquefaction is produced. The cells die in 5 minutes at 50 C. 



1 Yabe, K. On two new kinds of red yeast. Bull, of the Imp. University 

 of Tokyo, 1902.. 



2 Yabe. See reference for S. japonicus. 



