74 



MORPHOLOGY AND CULTURE OF MICROORGANISMS 



Every region seems to have its own forms and the characteristics of 

 the various forms seem to be as well fixed as those of beer yeasts. 



Wines are manufactured by the use of these yeasts. They are also 

 employed in distilleries. In breweries they are considered disease yeasts 

 and have a deleterious effect on the beer. 



B 



D 



FIG. 56. Wine and beer yeasts. A, S. ellipsoideus, young and vigorous; B, S. 

 ellipsoideus, (i) old, (2) dead; C, S. cerevisioe, bottom yeast; D, S. cerevisice, top yeast. 

 (Original.) 



S. pyriformis resembles in shape S. ellipsoideus, and in association 

 with Bacterium vermiforme produces ginger beer. 



S. vordermanni is concerned in the manufacture of arrack. It fer- 

 ments the sugar produced from rice by the molds, Mucor oryzce and Rhi- 

 zopus oryzce. 



S. fragilis and other yeasts have been found in kefir and other fer- 

 mented drinks made from milk. These yeasts working in conjunction 

 with bacteria produce alcoholic acid beverages. 



