SACCHAROMYCES APICULATUS. 405 



ture, each containing one species, Saccharomyces apiculatus will 

 multiply to a greater extent than the brewery yeasts in a 

 given interval of time. 



At the critical time of the year, the ferment, if present in 

 the wort in considerable quantities, may exist for a length of 

 time side by side with brewery yeasts, and will no doubt 

 retard its action a little ; but when the beer is transferred 

 to the lager cellar, the fungus remains inactive in the alcoholic 

 liquid, and frequently perishes. 



According to Will, the fungus frequently occurs in slight 

 traces in low-fermentation beer-yeast ; it may be caused to 

 multiply more freely by treatment with tartaric acid. 



Will mentions a case in which the yeast in a brewery in 

 Baden was so strongly infected with apiculatus that these 

 could be directly detected by their characteristic form, and, 

 indeed, were seen in large numbers. In the cask store and 

 in the deposit from diseased beer, cells of S. apiculatus are 

 occasionally found in considerable quantity in a living con- 

 dition, along with wild yeasts, and the flavour of the beer 

 may then be influenced. 



Miiller-Thurgau and Wortmann regard the fungus as 

 injurious to wine, for it not only directly prejudices the quality 

 of the wine and must, but also checks fermentation, and thus 

 gives rise to disease. 



The organic non- volatile acids (tartaric and malic acid) 

 present in fruit juices and grape must disappear by the culti- 

 vation of S. apic. It is possible that they serve as sources 

 of carbon for yeast, or else that they are decomposed in the 

 fermentation process. As fast as the acid is consumed a fresh 

 formation of acid takes place. 



Meissner has shown that 8. apic. can produce lactic acid ; 

 succinic acid is also produced. According to P. Lindner, 

 fruit ethers are formed. Will found that certain species 

 cause the production of a bouquet resembling amyl ether : 

 others give a fusty smell. According to Schander the pro- 

 nounced " Bockser " taste occurring in wines may be produced 

 by certain species of S. apic. Proteolytic enzymes are present, 

 and gelatine is readily liquefied by the organism. 



Many varieties or races of S. apic. are known. This was 



