YEASTS OR SACCHABOMYGETES 313 



tions, and in the vinous fermentation it usually succeeds the 

 Sacch. apiculatus. It is classed as a ' wild ' yeast, the spores 

 of which frequently occur in the atmosphere of breweries. 







Fig. 28.— Saccharomyces Pastoeianus I. 



The Sacch. pastorianus is one of the yeasts causing 

 ' disease ' of beer, to which it gives an unpleasant, bitter 

 taste. 



Saccharomyces Mycoderma. — The cells of this yeast are 

 oval, elliptical, or cylindrical, 6 to 7 /u. long and 2 to 3 //. 

 thick, united in freely-branching chains. Spore-forming 

 cells may reach 20 yu. long. One to four spores in each 

 mother-cell. This yeast forms the skin or * mould ' on the 

 surface of fermented liquids, without, however, exciting 

 fermentation. When forced to grow submerged in a sac- 

 charine liquid, it gives rise to a small quantity of alcohol, 

 but no growth takes place. 



Saccharomyces Conglomeratus. — Forms cells, which are 

 round and united in clusters, consisting of numerous cells 

 produced by budding from one or more mother - cells. 

 There are two to four spores in each mother-cell. This 

 yeast occurs on rotting grapes and in wine at the com- 

 mencement of the fermentation. 



Saccharomyces Minor.— Occurs in oval or spherical cells 

 6 /i in diameter, arranged in chains of 6 to 9 elements. 



