230 "DISEASES" OF BEER, 



and he states that these species multiply freely during the 

 primary fermentation when they are present in conjunction 

 with a brewery yeast. Unfortunately nothing is said as to 

 what took place subsequently in the infected beer during or 

 after storage. In another experiment, made by Lasche, some 

 bottles were filled with bright faultless beer, which had just 

 completed its primary fermentation. In some cases, however, 

 the beer was first passed through filter paper. Each of the 

 bottles was then inoculated with one of the four species of 

 Mycoderma mentioned. In one series the bottles were well 

 corked, and in the other the necks were merely plugged 

 with cotton-wool. It was found that in most of the bottles of 

 the latter series the Mycoderma cells developed vigorously, 

 whether the temperature was 10 or 4-6 C., and that the 

 beer was cloudy after five days. In the bottles which had 

 been well corked, only two of the species developed. The 

 experiments were discontinued at this point, and we, there- 

 fore, do not learn in what condition the beer was after the 

 completion of a normal storage. 



These, and the foregoing investigations, deserve to be 

 again taken up, and the experiments should be carried out in 

 the fermenting and lager cellars, and under conditions exactly 

 corresponding with those ordinarily prevailing in the brewery. 

 There are certainly considerable difficulties connected with 

 such experiments in the brewery, but the trouble will be well 

 repaid, for only in this way is it possible to solve these 

 practical questions. 



Finally, Lasche states that when beer, which had been 

 prepared with the help of pure cultivated yeast, was inocu- 

 lated with his species of Mycoderma, and then set aside at the 

 ordinary room-temperature, three of these varieties produced 

 cloudiness in from four to seven days, whilst in a fortnight the 

 beer had deteriorated as regards both taste and odour. The 

 fourth species, on the other hand, did not affect the beer in any 

 way under the conditions named. If, as I assume, the beer in 



