312 APPLIED BACTERIOLOGY 



Saccharomyces Ellipsoideus. — This yeast takes the most 

 important part in the fermentation of grape -juice and 

 other spontaneous fermentations. It is usually rounded or 

 ellipsoidal in shape, and it sometimes assumes a sausage 

 form. The cells average about 6 ti long, singly or united 

 in little branching chains. Two to four spores are found in 

 a mother-cell 3 to 3'5 //. in diameter. 



Jorgensen has published an investigation on the origin of 

 wine yeasts, from which it would seem that the Sacch. 

 ellipsoideus, associated with wine fermentation, is a peculiar 

 development, brought about by natural conditions, of the 

 Dematium or Chalara-Yike moulds which are always present 

 on grapes. Sorel also {Comp. rend., 1895, December 16) 

 has, by certain culture-methods, produced a yeast-like 

 ■development from Aspergillus orizce. 



Saccharomyces Apiculatus. — This yeast can hardly be said 

 to be a true saccharomyces, as it has not yet been ascer- 

 tained to have any spore formation. It is a very common 

 ' variety, however, and occurs in ferment-wine and spon- 

 taneously fermented beer ; on sweet succulent fruits, such 

 as grapes, cherries, plums, gooseberries, etc. The cells of 

 this yeast have a most characteristic citron shape (hence 

 the name), from the prominences at the end of which the 

 hudding takes place. The cells are 6 to 8 yu. long, and 

 2 to 3 ^ broad. This yeast invariably appears at the onset 

 ■of the vinous fermentation of grape- juice, but it soon gives 

 vyay to the Sacch. ellipsoideus and Sacch. pastorianus. It 

 only gives rise to a very feeble alcoholic fermentation. 



Saechaxomyces Pastorianus. — This yeast — of which three 

 varieties, known as I., II., and III., have been isolated by 

 Hansen — is very polymorphic in shape. The cells are oval 

 or club-shaped, and also occur as elongated, ellipsoidal, 

 pear-shaped cells. Two to four spores are found in a 

 jnother-cell. It takes a part in many spontaneous fermenta- 



