TOP-FERMEXTATION YEASTS. 337 



The cells of the film have a very different appearance from 

 those seen in the fermentation-stage. Many of them are 

 much lengthened and irregularly twined ; some have developed 

 a ramified mycelium. 



If developed at a low temperature, the spores are small, 

 coherent, granulated. At 11 to 12 C. no spores appear 

 within a fortnight ; at 25 C., a very scanty spore-formation 

 takes place in forty hours. 



When the principal fermentation was broken off, the liquid 

 contained 2-49 per cent, by vol. of alcohol ; in the following 

 two periods 0-86 and 0-12 per cent, by vol. were formed. 



Acid-production : 5-2. 



Agreeable smell and fine aromatic taste. 



6. ^(Fig. 66. 6, and Fig. 67, 6.) 



The cells are round, oval, and elongated during fermenta- 

 tion, all forms occurring in chains ; isolated round giant cells 

 occur. 



The yeast lies rather compact in flask ; it requires strong 

 shaking to distribute the cells equally throughout the liquid. 



Film-formation : After 26 days the surface growth forms 

 a ring of yeast cells on the wall of the flask ; only slight indi- 

 cations of film-formation. After 31 to 32 days the film had 

 not developed further. 



The cells of the ring-growth cannot be distinguished from 

 those occurring during alcoholic fermentation. 



If developed at a low temperature, the spores are com- 

 paratively small, granulated, with no distinct vacuoles. At 

 11 to 12 C., for seven days, very few spores are formed ; at 

 25 C., for forty hours, a scanty spore-formation takes place. 



When the principal fermentation was broken off, the liquid 

 contained 1-85 per cent, by vol. of alcohol ; during the following 

 two periods 0-65 and 0-2 per cent, by vol. were formed. 



Acid-production : 6. 



Agreeable smell and slightly aromatic taste. 



7. (Fig. 66, c, and Fig. 67, c.) 



During fermentation round and oval cells, some free, others 

 linked in short chains. 



22 



