334 MICRO-ORGANISMS AND FERMENTATION. 



If developed at a low temperature, the spores are of very 

 varied size, with comparatively feeble refractivity, and without 

 distinct vacuoles. Partition- wall formations occur. At 11 to 

 12 C., in seven days, only rudiments of spores appear ; at 

 25 C., in forty hours, spores are very freely formed. 



When the principal fermentation was broken off, the liquid 

 contained 2-26 per cent, by vol. of alcohol ; during the fol- 

 lowing two periods 0-79 and 0-00 per cent, by vol. were formed. 



Acid-production : 5-5. 



Disagreeable smell and taste. 



4. (Fig. 64, d, and Fig. 65, d.) 



During fermentation, colonies consisting of many small 

 spherical cells occur, and among these spherical giant cells. 



The yeast lies loose in flask ; if slightly shaken, it is dis- 

 tributed like a cloud throughout the whole liquid. 



Film-formation : After 31 to 32 days, only the merest trace. 



The cells of the ring-growth occur in colonies, which some- 

 times contain upwards of a hundred cells, all derived from a 

 single cell ; the youngest growths are elongated and very 

 narrow. 



The spores, if developed at a low temperature, are small 

 and vacuolised. At 11 to 12 C., even after a fortnight, no 

 spore-formation ; at 25 C., for forty hours, a very scanty 

 development of spores. 



When the principal fermentation was broken off, the liquid 

 contained 1-8 per cent, by vol. of alcohol ; during the following 

 two periods 1 and 0-82 per cent, by vol. were formed. 



Acid-production : 5-5. 



Disagreeable smell and taste. 



5. (Fig. 66, a, and Fig. 67, a.) 



During fermentation most cells are free, medium-sized, and 

 oval. 



The yeast lies rather loose in flask ; if shaken, it is not 

 distributed equally in the wort, but separates into clots. 



Film-formation : After 31 to 32 days a distinct film, which, 

 however, does not cover the whole surface, and subsequently 

 develops slowly. 



