362 MICRO-ORGANISMS AND FERMENTATION. 



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

 short sausage-shaped and small cells are more frequent. 



Hansen found this species in pressed yeast. Its behaviour 

 towards the sugars is similar to that of the last species, though 

 it develops a greater fermentative activity in solutions of 

 saccharose and dextrose. Like the former species, it yields 

 in wort only small quantities of alcohol. It does not ferment 

 maltose solutions." It inverts saccharose. 



Experiments, carried out by Hansen in practice, have 

 shown that this species does not produce any disease in beer, 

 even when present in considerable quantities either at the 

 beginning or end of the primary fermentation, or when it is 

 added after the storage of beer. 



This is of special interest, as Sacch. exiguus was formerly 

 regarded as a disease-producing species. 



Saccharomyces Jorgensenii Lasehe 



also belongs to this group of the Saccharomycetes. The growth 

 consists of small round and oval cells. The optimum tem- 

 perature for spore-formation is 25 C., the temperature limits 

 being 8 and 30 C. At temperatures above 30 C. the growth 

 dies rapidly. A true film-formation has not been observed ; 

 in old cultures only a very feeble yeast ring forms, consisting 

 of round and oval cells. In gelatine it yields colonies which 

 resemble those of low-fermentation brewery yeast. Wort- 

 gelatine is slowly liquefied. The streak-culture is a dirty grey 

 colour, and has smooth edges. This species ferments saccharose 

 and dextrose, but not maltose. Consequently it is suppressed 

 when mixed with cultivated yeasts and grown in malt- wort. 

 In wort it yields only 0-89 per cent, by weight of alcohol. 

 In " temperance beer/' according to Lasche's statement, it 

 produced a strong turbidity. 



Saccharomyces Zopfii Artari 



was discovered by Zopf in the syrup of a sugar factory. The 

 cells are small, spherical, or elliptical. The temperature 

 maximum for budding in wort is 33 to 34 C., the optimum 

 28 to 29 C. The temperature maximum for spore-formation 



