198 STUDIES ON FERME>'TATIOX. 



Without dwelling- longer on the practical consequences likely 

 to result from the ideas which we have just expressed, we shall 

 proceed to describe two new alcoholic ferments, which differ 

 widely from those already mentioned. 



New " Iliijh " Ferment. — We met with this ferment acci- 

 dentalh% under the following circumstances : — On February 

 12th, 1873, we had brewed in the laboratory about 2\ hectolitres 

 (rather over 50 gallons) of wort, 10 litres (about two 

 gallons) of which were set aside to cool in a white-iron trough, 

 and left during the night exposed to free contact with air in the 

 underground part of the laboratory, where we have a small 

 experimental brewery. Next day we put some of this latter into 

 a bottle ; the wort soon began to show evidence of change, various 

 productions made their appearance on the surface of the liquid, 

 and a deposit of yeast settled at the bottom. On May 23rd, 

 Ijerceiving bubbles of gas and a steady fermentation set up in 

 the wort, which remained all the time corked up, and fearing 

 that the bottle might burst by the increasing internal pressure, 

 we drew the cork. A considerable liberation of gas at once 

 took place, accompanied by a voluminous foam w^iich half 

 emptied the bottle. A microscopical examination of the deposit 

 from the disturbed liquid led to the discovery of a very 

 homogeneous yeast, associated with various other organisms ; it 

 was clearly a yeast which we had not hitherto met with 

 amongst the spontaneous ferments which we had had occasion 

 to study. Thinking that this might be a new species of fer- 

 ment which would probably produce a beer that was also 

 unknown, we set to work to purify it by cultivation in flasks of 

 pure wort, during the months of May, June, and July. Our 

 last growths, of August 4th, 1873, were preserved, in order 

 that we might assure ourselves of the purity of the beer, and, 

 consequently, of the ferment. On November loth its purity 

 was established. On that date we made some beer with this 

 ferment, which had now been left to itself for several months 

 in contact with pure air. The beer which we obtained 

 resembled no known variety ; consequently the ferment must 



