126 BACTERIA 



Saccharomyces Cerevisice. Oval or ellipsoidal cells ; repro- 

 duction by budding; ascospores, rapidly at 30° C, slowly 

 at 12° C, not formed at all at lower temperatures; film 

 formation, seven to ten days at 22"" C. ; an active alcoholic 

 ferment, producing in a fortnight in beer wort from 4 to 6 

 per cent, by volume of alcohol (Jorgensen). This species 

 is a typical English " high" yeast, possessing the power 

 of " inverting " cane-sugar previous to producing alco- 

 hol and carbonic acid. It is said to have no action on 

 milk-sugar. 



Saccharomyces Ellipsoideus I. Round, oval, or sausage- 

 shaped cells, single or in chains; ascospores in twenty-four 



S. Ellipsoideus S. Pastorianus 



hours at 25° C. (not above 30° C, not below 4° C). Grown 

 on the surface of wort-gelatine, a network is produced by 

 which they can be recognised (in eight to twelve days at 

 33° C). At 13-15° C. a characteristic branching mass is 

 produced. It is an alcoholic ferment as active as 5. cere- 

 visicB. S, Ellipsoideus IL Round and oval, rarely elong- 

 ated, a widely distributed yeast, causing *' muddiness *' in 

 beer and a bitter taste. It is essentially a ** low " yeast. 



Saccharomyces Conglomeratus is a round cell, often united 

 in clusters, and occurring in rotting grapes, and at the com- 

 mencement of fermentation. 



