ALCOHOLIC FERMENTS. 203 



for some time, small mould-like particles are formed ; some of 

 these swim in the liquid, others settle to the bottom. These 

 particles consist of mycelium-like colonies of practically the 

 same character as the film-formations of the six species 

 previously described ; they are also built up of cells, which 

 are readily separated at the point of union. The ascospores 

 are kidney-shaped, spherical, or oval. After cultivation for 

 two to three months in wort contained in two-necked flasks, 

 there were only traces of film-formation with few sausage- 

 shaped and oval cells. 



This yeast is one of those species which develop a mycelium 

 under certain conditions of culture on a solid nutritive medium. 



In beer- wort it yields only 1 to 1*3 per cent, (by volume) 

 of alcohol, even after long standing. It does not ferment 

 maltose ; it inverts saccharose ; and in nutritive solutions of the 

 latter, and of dextrose, it yields considerable quantities of alcohol. 



The maximum temperature for spore-formation lies between 

 32 and 34 C., the minimum between 4 and 8 C., the 

 optimum between 22 and 25 C. The growth yields quicker 

 and more abundant spore-formation if cultivated in yeast- 

 water, or wort with 10 per cent, dextrose (KLOECKLER). 



In agreement with his theory that maltose is split up by a 

 particular enzyme differing from invertase, and only subse- 

 quently fermented, EMIL FISCHER found that an aqueous 

 extract of the pulverised growth of this yeast decomposes 

 saccharose, but not maltose. 



SACCHAROMYCES EXIGUUS (REESS), (HANSEN) 



develops a growth in wort, the cell-forms of which most closely 

 correspond to the species described by REESS under the above 

 name. It is, however, impossible to determine whether REESS 

 was really dealing with this species, since any Saccharomyces 

 species may, under certain conditions, form a preponderating 

 number of similar small cells. 



This species only gives scanty spore-formation and weak 

 film-formation, but it yields a well-developed yeast-ring. The 

 cells of the film resemble those of the sedimentary yeast, but 

 short sausage-shaped and small cells are more frequent. 



