194 "DISEASES" OF BEER, 



It still remains to be ascertained what will occur when 

 the beer becomes infected with the two wild yeasts after 

 the completion of the storage period, that is to say, in the 

 small casks and bottles from which the beer passes direct to 

 the consumer. For these experiments I employed bottles 

 cf clear, colourless glass, and of the customary size and 

 form as ordinarily employed in the trade for the bottling 

 of beer ; the capacity of each bottle is about 350 cc. After 

 they had been cleaned, they were sterilised, together with the 

 corks. The greatest care was taken in filling the bottles, 

 after which the two disease yeasts were introduced, and the 

 bottles carefully corked. They were then well shaken, and 

 finally put away in a dark place, and at the ordinary room- 

 temperature. The infection was in all cases abundant, but 

 the amount of yeast introduced was such that the beer 

 remained bright directly after shaking. The flasks which 

 were not infected, and which were placed with the others as a 

 control, were of course also agitated and were treated in 

 every way like the latter, the only difference being that they 

 were not infected. Moreover, in these, as in the earlier 

 experiments, importance was attached to the imitation of the 

 conditions obtaining in practice. The beer ordinary lager 

 beer was from the Old Carlsberg brewery, and it was only 

 in a few cases that I employed beer from some of my own 

 fermentations with pure cultures of low brewery yeast. The 

 chemical composition of the latter beer approximated to that 

 of the ordinary lager beer, the alcohol of which amounted to 

 4 ' 3 per cent., and the extract 5 6 per cent. The three 

 following examples will serve as illustrations of the experi- 

 ments which were carried out with reference to the above 

 questions. 



V. Series of Experiments. Young vigorous growths of the two 

 disease yeasts, which had been developed in ordinary wort, were 

 introduced into twelve bottles of lager beer. Three of the bottles 

 were inoculated each with one drop of Sacch. Pastorianus III., and 

 three diops of the same species were introduced into each of three 



