578 APPENDICES. 



with the naked eye. II. Round, oval, and rarely elongated 

 cells. They produce yeast-turbidity. There are two so-called 

 disease-yeasts allied to this species. The colonies of one kind form 

 a network. This yeast causes turbidity in beer, and a bitter after- 

 taste. In the other kind the colonies are sharply denned. It 

 produces a disagreeable aromatic taste to beer, and an astringent 

 after- taste. It is widely distributed, and is the principal agent in 

 .accidental fermentation. 



Saccharomyces eonglomeratus (Reess). Cells round, 5 to 

 6 fji in diam., united in clusters, consisting of numerous cells 

 produced by budding from one or a few mother- cells. There are 

 2 to 4 spores in each mother-cell. They occur on rotting grapes 

 and in wine at the commencement of fermentation. 



Saccharomyces exiguus (Reess). Conical or top-shaped 

 cells, 5 p long, and reaching 2'5 /x, in thickness, in slightly 

 branching colonies. Spore-forming cells are isolated, each contain- 

 ing 2 or 3 spores in a row. They occur in the after-fermentation 

 of beer; but, according to Hansen, they do not produce disease 

 in beer. 



Saccharomyces Jb'rgensenii (Lasche). Cells small, round 

 or oval. On the surface of wort-gelatine the culture is greyish- 

 white, and the gelatine is slowly liquefied. They ferment saccharose 

 and dextrose, but not maltose. When grown in wort with other 

 yeasts they are rapidly crowded out. 



Saccharomyces pastorianus, I. Cells oval or club-shaped. 

 Colonies consist of primary club-shaped links, 18 to 22 p long, 

 which build lateral, secondary, round or oval daughter-cells, 5 to 

 6 p long. Spores 2 to 4. They occur in the after- ferment at ion 

 of wine, fruit-wines, or fermenting beer, and in the air of breweries. 

 They produce a bitter taste and unpleasant odour and turbidity 

 in beer. II. Cells mostly elongated, but also oval or round. 

 Cultivated on the surface of gelatine and yeast- water a growth is 

 produced with smooth edges, by which it can be differentiated 

 from No. III. They occur in the air of breweries, but do not 

 produce disease in beer. III. They produce yeast-turbidity in 

 beer. On the surface of yeast- water gelatine the cultures, after 

 sixteen days, have hairy edges. 



Saccharomyces apiculatus. Cells lemon -shaped, both ends 

 bluntly pointed, 6 to 8 /x long, 2 to 3 p wide. Budding occurs only 

 at the pointed ends. Rarely united in colonies. Spores unknown. 

 They occur with other yeasts in various accidental fermentations 

 -and in ripe fruits. 



