ALCOHOLIC FERMENTS. 



167 



Microscopic appearance of the cells in the films : 



At 20 28 C : Nearly the same forms as in the sediment- 

 ary yeast ; also irregular sausage-shaped cells. 



At 153 C. : Mostly oval and round cells. 



In old cultures of films the cells are smaller than in the 

 sediment; very irregular and sometimes almost thread-like 

 cells are found. 



Streak cultures of this species in gelatine yeast-^vater 

 give, after sixteen days at 15 C., growths with compara- 

 tively smooth edges, and in this respect it also differs from 

 the following species. 



SACCHAROMYCES PASTORIANUS III. HANSEN. 

 (Figs. 41, 42.) 



FIG. 41. 



Saccharomyces Pastorianus III. Hansen. Cell-forms of young sedimentary 

 yeast, after Hansen. 



Top-fermentation yeast. 



Sedimentary forms grown in wort: mostly elongated, 

 sausage-shaped, but also large and small oval and round 

 cells (Fig. 41). 



It was separated from a bottom-fermentation beer which 

 showed yeast-turbidity, and has been proved by Hansen to be 



