YEASTS 



61 



In nutrient solutions they swell, burst the mother cell, become free 

 and germinate by budding, usually producing vegetative cells directly, 

 though occasionally producing first a short promycelium (S. ludwigU). 



In Schizosaccharomyces octosporus the ascus is formed by the fusion 

 of two cells. Sometimes in other species, two or more spores in one cell 

 will fuse before germination. 



Staining with warm carbol-fuchsin and partial decolorization with 

 weak acetic acid leaves the spores red and the cell colorless. 



Fig. 42. — Spore-bearing cells. A. S. pasteurianiis. {After Bioletti.) B. Sch. 

 octosporus. {After SchiSnning.) C. S. anomalus. {After Kayser.) 



Cytology oj Yeasts* 



General Structure or Yeasts. — ^The structure of yeasts in no 

 way differs from that of the other fungi, only it is seemingly more complex 

 and consequently more difl&cult to interpret on account of the abundance 

 of the stainable granulations which sometimes accumulate in the cells 

 and occasionally hinder the differentiation of the nucleus. This explains 

 why it has until recently remained a subject of controversy. It is now 

 fairly well understood. 



• Prepared by A. Guilliermond. 



