YEAST FROM KOUMYS 267 



complished easily. They appear at the end of five hours at 25 C. on 

 plaster blocks. They may also be observed in cultures on gelatin, in 

 hanging drops and in the scums of old cultures on liquid media. The 

 ascospores are to the number of from one to eight per asc. Their 

 form and dimensions are variable. More often they are elliptical 

 but sometimes they are hemispherical. They germinate by ordinary 

 budding after absorbing the wall of the asc. The colonies on nutrient 

 agar, in plates, are circular and torpedo shaped. In stabs, the growth 

 is along the line of inoculation and increases towards the surface. 

 Giant colonies show a center with a crateriform concavity with radii 

 out from the center. Saccharomyces lactis ft produces in liquid media 

 with sugars, a scum and a ring in which the cells have somewhat the 

 form of a mycelium with ascospores. It acts as a bottom yeast. An 

 active fermentation is produced during which a feeble aroma may be 

 noticed. Beer wort is distinctly decolorized and there is formed at the 

 end of five and a half months 7.93 per cent of alcohol by volume. In 

 milk an energetic fermentation is produced at 23-25 C. It ferments 

 saccharose, lactose, d-galactose and dextrose but has no action on 

 maltose. It seems to be closely related to Saccharomyces fragilis 

 (Jorgensen). 



YEAST FROM KOUMYS. Schipin 



This yeast was isolated from koumys by Schipin. Along with a 

 few bacteria, it contributes to the formation of koumys by inducing 

 a fermentation in milk with a small quantity of lactic acid. Ru- 

 binsky l has given a detailed description of this organism. In hanging 

 drops this yeast possesses round or oval forms which contain at one 

 of their extremities or in the middle a large refractive granule. In 

 old cultures on agar, in Petri dishes (after four or five weeks) the 

 cells are often elongated. Old cells always contain granules. 



Schipin has obtained sporulation in this yeast. Rubinsky has also 

 observed on plaster blocks the formation of six or eight globules which 

 look like ascospores but it is not certain that they are true ascospores. 

 On gelatin plates, this koumys yeast exhibits mediocre development 

 during the first few days. At the end of three days, it forms surface 

 colonies of about 2-3.5 millimeters and the deep colonies are round. 

 The culture gives off an aromatic odor often acid. On gelatin stabs, 

 the culture takes the form of a bottle and has a flat white color some- 

 times yellow along the line of puncture. On gelatin added to bouillon, 

 after 2 to 3 weeks, the colonies have a center sometimes soft and shiny. 

 In cabbage bouillon, the colonies have a peculiar appearance. The 

 1 Rubinsky, B. Studien iiber den Koumiss. Cent. Bakt. 28, 1910. 



