204 "DISEASES" OF BEER, 



infected with the yeast mentioned at the conclusion of the 

 storage period. The method was the same as that adopted 

 in the experiments with Sacch. Pastorianus III. and Sacch. 

 ellipsoideus II., which were described above. I made use 

 partly of a young vigorous growth which had been cultivated 

 in flasks of wort, partly of cask sediments which were 

 obtained after storage of the beers produced in the experi- 

 ments just described, and partly also of yeast sediment 

 from bottles of ordinary lager beer which had been infected 

 with Sacch. exiguus, and subsequently kept for a time in 

 the room ; these bottles had been frequently shaken, 

 in order to hasten the growth of the yeast. The yeast 

 obtained in these different ways was employed in a thin 

 condition ; in some experiments two drops, and in others 

 three drops, were added to the bottles under investigation. 

 In spite of this considerable contamination, no effect could 

 be detected, and, after fourteen days, none of the bottles 

 showed any signs of yeast turbidity. 



Main Result. The experiments just described show that 

 a considerable addition of Sacch. exiguus at the beginning of 

 the primary fermentation, or at its end, or after storage, does 

 not produce any disease in lager beer. As the experiments 

 were carried out entirely under the conditions prevailing in 

 the brewery, the results obtained may, with perfect justice, 

 be applied to practice. 



It is, of course, not possible to determine of what kind 

 were the yeast cells referred to at the time when Sacch. 

 exiguus played such an important part in the zymotechnic 

 literature. Since the problem of the diseases of beer caused 

 by alcoholic ferments has been attacked experimentally, it 

 has no longer been a question of this species. The possibility 

 is, indeed, not excluded that a disease yeast consisting of 

 small cells may some day be found, and assumed to be the 

 old Sacch. exiguus of Reess ; but, for the present, this dread 

 has disappeared from the zymotechnic field. 



