PRODUCED BY ALCOHOLIC FERMENTS. 191 



was 2 C. The remaining portion of the beer was left to ferment further, 

 and, after ten days from the commencement, the extract in both A and B 

 was 6-7 per cent. Ball. The beer was then drawn off into casks, and 

 these were placed in the same lager cellar with the first portions. 



After the two first casks had been in the lager cellar for -2\ months, 

 the beer, which previous to storage had a gravity corresponding with 

 7*5 per cent. Ball., was drawn off into clean bottles of clear colourless 

 glass, and these were then placed in a dark cupboard in the laboratory. 

 At the time of bottling both kinds of beer were, as in the previous 

 experiments, free from all trace of yeast turbidity ; but even after one day's 

 standing, the development of yeast in the beer B was noticeable ; after 

 five days B was distinctly cloudy, whilst A was still bright. The contents 

 of the other casks, the gravity of which, previous to storage, corresponded 

 with 6' 7 per cent. .Ball., were treated in the same manner after three 

 months' storage. The beer from both B and A proved to be perfectly 

 stable ; its extract amounted to 5 9 per cent. Ball. 



These experiments thus show that the disease can still de- 

 velop when Sacch. ellipsoideus II. constitutes only ^ part of the 

 pitching yeast, but only when the beer had an extract of at least 

 7 5 per cent. Ball, at commencement of storage, and when under 

 these conditions the storage was discontimied after 2 months. 

 On the other hand, when the fermentation was carried further 

 in the fermenting vessel, so that the extract had diminished to 

 6 ' 7 per cent., and the beer then stored for at least three months > 

 the disease did not manifest itself. 



This experiment was repeated, but with the modification 

 that the yeast used for pitching B contained ^ part Sacch. 

 Pastorianus III. in the place of Sacch. ellipsoideus II. The 

 main result was the same as before ; it was found, however, 

 in this and in some other experiments, that the latter species 

 was the more objectionable one. 



Finally, experiments were made on a large scale, in order 

 to determine what is the effect when infection occurs at the 

 end of the primary fermentation. 



III. Series of Experiments. The lager beer and export beer used in 

 these experiments were taken from the fermenting cellar of the Old 

 Carlsberg brewery at the stage when ready for removal to the lager 

 cellar. Three casks, A, B, and C, each of i6| liters capacity, were filled 

 with each kind of beer. B was then inoculated with 10 cc. of the yeast 



