TORULA COMMUNIS 309 



KAYSER'S YEAST 



Secured from milk at a farm in Brie, Kayser l found that this yeast 

 possessed cells from 6 to 8/x, long and 3 to 5ju wide. It forms neither 

 casease nor rennin. Like the two preceding species, it ferments sac- 

 charose and lactose (the lactose as easily as the saccharose), d-galac- 

 tose, and dextrose but acts with difficulty on maltose. The thermal 

 death point is 55 C. for moist cells and 90-100 C. for dry cells. On 

 gelatin, it looks like the preceding yeast and is distinguished only by 

 the fact that the fibrous appearance is less pronounced. 



TORULA COMMUNIS. Browne 



Browne 2 has found a Torula the most abundant organism in raw 

 sugar from Cuba. A similar organism was also found in raw sugar 

 and soft refined sugars from the British West Indies. Owen 3 has also 

 mentioned a similar organism. The colonies on raw sugar agar, 



Fig. 141-B. Magnified Cells of Torula communis (after Browne). 



according to Browne, appear first as small white cysts which are pointed 

 under the microscope. These cysts increase in size to a diameter of 

 0.2-0.5 mm. until they reach the surface of the agar after which they 

 spread out in all directions. The colony gradually assumes a cir- 

 cular shape from 3-10 mm. in diameter and is grayish white in color. 

 Old colonies are brownish in color. Under high power of the micro- 

 scope, no mycelium is seen. The cells are separate and look like 

 yeasts. Torula communis grows readily in all concentrations of sugar 

 solutions. A granular deposit is formed and, after a time, a thin 

 marginal scum. There seems to be slight evolution of gas. No 

 froth or foam is formed as is often present with strongly fermenting 

 organisms. The action on raw sugar seems to be a destruction of the 



1 Kayser, E. Contribution physiologique des levures alcooliques de la lac- 

 tose. Ann. Past. Inst. 5, 1891. 



2 Browne, C. A. The Deterioration of Raw Cane Sugar. A Problem in 

 Food Conservation. J. Ind. Eng. Chem. 10 (1918), 178-190. 



3 Owen. Louisiana Planter, 56, 173. 



