PRODUCED BY ALCOHOLIC FERMENTS. 195 



other bottles ; six bottles were similarly infected with Sacch. ellipsoideus 

 II. ; three bottles which had not been infected were kept as a control. 



After ten days all were still bright, and showed no appreciable sedi- 

 ment. Four days later this was still the case with the uninfected beer. 

 The bottles infected with Sacch. Pastorianus III. showed a slight sediment, 

 which rendered the beer slightly cloudy when shaken. The bottles into 

 which the other disease yeast had been introduced contained at this time 

 a more pronounced sediment. The three bottles to which one drop had 

 been added became slightly cloudy when shaken, whilst those to which 

 three drops were added exhibited a marked yeast turbidity. 



VI. Series of Experiments. Twenty-four bottles were inoculated, 

 twelve with one and twelve with the other species. The yeast had been 

 grown in bottles of lager beer, which had stood for about ten days at the 

 ordinary room-temperature, and which were frequently shaken in order to 

 hasten the growth. It was in a vigorous condition, and was employed in 

 moderately thin consistency. Twelve bottles were inoculated with Sacch. 

 Pastorianus III., four of which received one drop each, four others 

 two drops each, two more four drops, and two eight drops. In the same 

 way twelve bottles were likewise inoculated with Sacch. ellipsoideus II. ; 

 three bottles were kept as a control. 



After seven days an appreciable sediment was found only in the two 

 bottles to which eight drops of Sacch. ellipsoideus II. had been added ; 

 the beer in these became slightly cloudy on shaking, whilst in all the 

 others it was bright and showed no sediment. After fourteen days the 

 bottles which had not been infected, and also ten of those infected with 

 Sacch. Pastorianus III., were still perfectly bright, and showed no appre- 

 ciable development of yeast ; the two bottles which had received eight 

 drops of this yeast were also bright, but on closer examination a slight 

 sediment could be detected, and on agitation the beer became slightly 

 cloudy. The four bottles which had been inoculated with one drop of 

 Sacch. ellipsoideus II. were bright, whilst the remainder showed signs of 

 yeast turbidity, varying according to the amount of infection. On agita- 

 tion, however, only those which had been most strongly infected (with 

 four and eight drops) became distinctly cloudy. 



Some experiments which were carried out in the same 

 manner as those of the last two series, but in which cask 

 sediment was used, gave essentially the same result. This 

 sediment was obtained from some of the lager casks men- 

 tioned in the description of the experiments, in which the 

 two disease yeasts were added with the pitching yeast at the 

 beginning of the primary fermentation. The cells which were 

 introduced into the bottles in these experiments had therefore 



O 2 



