248 THE BLASTOMYCETES 



It takes place most rapidly (twenty-eight hours) at 25 C., most slowly 

 (nine days) at 8 '5 C., and ceases at 29 C. and at 4 C. 



Film Formation. This appears in the form of small flakes, most 

 rapidly (seven to ten days) at 26 to 28 C., most slowly (five to six 

 months) at 3 to 5 C., and ceases altogether at 34 and 2 C. The elon- 

 gated or sausage form cells predominate, but large and small round and 

 ovoid cells are also found in the sediment in the films at from 20 to 28 C. 



Biological Characters. In cultures grown on yeast-water gelatine, 

 at the end of sixteen days the colonies exhibit peculiarly fringed edges. 

 Grown in wort, it gives rise to a top fermentation, causing considerable 

 turbidity, and producing alcohol and carbonic acid gas. 



SACCHAROMYCES APICULATUS. 



found in fermented wine and spontaneously fermented beer, and 

 in hot seasons on sweet succulent fruits cherries, plums, grapes, etc. 

 In winter it is found in the soil beneath the trees that bear these 

 summer fruits. 



Microscopical Appearances. In cultivation fluids the cells are 

 lemon-shaped, the buds are lemon-shaped, and in older cultures oval. 



Spore Formation absent. Hence it cannot be classified as a true 

 yeast. 



Biological Characters. When dried in a thin layer it is killed, 

 which accounts for it not developing on unripe fruit. It is a bottom fer- 

 mentation yeast, causing feeble alcoholic fermentation. It does not invert 

 cane sugar, but acts on dextrose in yeast water, the fermentation being 

 incomplete. Mixed with Saccharomyces it retards the action of the 

 latter. 



SACCHAROMYCES ANOMALUS. 



Found in brewery yeast. 



Microscopical Appearances. Small oval cells. 



Spore Formation present, in the form of hemispheres with 

 projecting rims, whereby they are shaped like a hat; the optimum 

 temperature for their development is 25 C. 



SACCHAROMYCES MARXIANUS. 



First found in wine. 



Microscopical Appearances. Small ellipsoidal and egg-shaped 

 cells, with sausage-shaped cells here and there ; often arranged in 

 colonies. 



