338 NON-SACCHAROMYCETES OR DOUBTFUL YEASTS 



This species ferments maltose, but has no action on saccharose or 

 lactose. It seems to cooperate with Torula lebenis in the fermenta- 

 tion of milk but only when it is associated with Streptococcus lebenis. 



DOMBROWSKTS l MYCODERMA FROM MILK 



Mycoderma lactis a. This yeast was encountered by Jensen and 

 by Collau in various milk products, particularly in butter from Fin- 

 land. The cells are elongated, rectangular, with rounded angles; 

 sometimes they are slightly curved. Besides these, one may find 

 numerous spherical cells. The cells enclose small droplets of fat. 

 The dimensions of the cells are quite variable. After 96 hours on beer 

 wort, the length may be 14.72, 13.0, 9.5, 8.42, 5.5 M and their width, 

 4.15, 14.15, 3.7, 3.7, 3.2 ju. Often the cells may be longer than 27 M- 

 At the end of 24 hours, this species forms on carbohydrate liquid 

 media, a well-developed scum. The wort becomes very cloudy and 

 clears itself after 10 days. In must fermentation is brought about 

 with the escape of an aromatic odor like that of ethyl ether. After 

 five and one half months, 6 grams of alcohol are formed per 100 c.c. 

 of must. In milk at 23-25 C., there is no fermentation. 



On beer wort gelatin plates, the colonies are flat with a farina- 

 ceous covering in the midst. In gelatin stabs, development extends 

 down to 3.5 ccm. About the line of inoculation, one may see extended 

 lines which decrease in length as one goes toward the bottom of the 

 tube. 



Giant colonies have a membranous aspect with a grayish white 

 color. In the center, a crateriform concavity exists about which 

 is a raised portion. The border is finely fringed and possesses light 

 folds. This yeast ferments only dextrose. The fermentation is ac- 

 companied with the formation of ethers. 



Mycoderma lactis ft. Collau isolated this species in Copenhagen 

 from a culture of starter used in cream ripening. It is closely related 

 to the Mycoderma described above but is distinguished by the size 

 of its cells and by its fermenting ability. The appearance of the giant 

 colonies is also a distinguishing characteristic. The cells may reach 

 12.87;u in length and 3ju in width. 



On beer wort, this yeast acts like the preceding one; however, it 

 has a very feeble fermenting ability. At the end of five months, only 

 4.2 grams of alcohol per 100 c.c. are formed. 



The colonies on gelatin plates are much cut up and suggest the 

 structure of molds. The cells are very much elongated, united and 



1 Dombrowski, W. Die Hefen in Milch und Milchprodukten. Cent. Bakt. 

 28, 1910. 



