214 



MICRO-ORGANISMS AND FERMENTATION. 



SACCHAROMYCES ACIDI LACTICI (GROTENFELT). 



GROTENFELT has described under this name a species of 

 Saccharomyces which, when added to sterilised milk, produces a 

 pronounced curdling with formation of acid. On gelatine and 

 agar-agar it forms white porcelain-like colonies, and on potatoes 

 it yields broad, moist patches of a whitish-grey colour, soon 

 turning brown. In puncture cultivations in gelatine short 

 bottle-shaped growths develop from the point of inoculation in- 

 wards. The cells are elliptical, 2-0 to 4 '3 5 M in length, and 

 1-50 to 2-90 fji in breadth. 



When a solution of milk-sugar is inoculated in the presence 

 of calcium carbonate, and the product distilled, alcohol can be 

 detected. In a neutral, 3 per cent, solution of milk-sugar, 

 Saccharomyces acidi lactici yielded 0*108 per cent, of acid in 

 eight days. 



SACCHAROMYCES FRAGILIS, N. SP. (Figs. 66 and 67.) 



While the budding fungi found in kephir, and described by 

 others, do not form spores, a genuine Saccharomyces has been 



FIG. 66. Saccharomyces fragilis. Young vegetation in lactose yeast-water. (HOLM.) 



discovered in the author's laboratory, which we have called 

 Saccharomyces fragilis on account of the feeble power of resist- 

 ance of the cell-wall. 



The growth consists of relatively small, oval, and longish 

 cells (Fig. 66), which refract light feebly and in a peculiar 

 way. At the room temperature, this species behaves as a low- 



