74 stui)ip:s on fermentation. 



On May 29th, 1873, eighteen flasks, free from air and with 

 necks drawn out to a fine point, containing must, were taken 

 into one of our rooms at the Ecole Normale. A jet of gas from an 

 ordinary burner was passed over the surface of the glass down to 

 the surface of the liquid, with the object of burning any particles 

 of dust that might have been deposited from the atmosphere of 

 the laboratory ; the points of the flasks were then broken with 

 a pair of ordinary scissors that had been passed through the 

 flame of a spirit lamp ; and, lastl}', the tops of the flasks were 

 taken off", just above the surface of the liquid, and the eighteen 

 flasks thus became transformed into eighteen basins, each con- 

 taining about 100 c,c. (about 3| fluid ounces) of grape must. 

 These eighteen basins were placed on a table in the room, and 

 left there for five daj'S, precautions being taken to prevent any 

 one from entering the room. 



The basins were examined on June 2nd : they all contained 

 little flakes of floating mycelium, but none of them had any 

 white streaks on their sides — a proof that they were destitute of 

 torulce — the liquid had remained very bright. AYith the contents 

 of nine of the basins we filled two long-necked flasks that we had 

 prepared for our purpose — that is to say, had heated to a 

 certain point, just before using them, with the object of re- 

 moving from their sides any foreign germs which they might 

 have picked up in the laboratory. Up to July 10th, when we 

 deemed it useless to carry our observations further, these flasks 

 presented no signs of fermentation whatever. With the con- 

 tents of the remaining nine basins, we filled two other long- 

 necked flasks, but before doing so, we kept the basins for twenty- 

 four hours (June 2nd to 3rd) in the basement of our laboratory. 

 These two flasks soon set up an active fermentation, and de- 

 posited an abundance of yeast — an additional proof of the great 

 difference in character of the germs floating about the room 

 and those floating about the laboratory. 



On June 3rd we exposed, simultaneously, in the aforemen- 

 tioned room and also in our laboratory, seven basins prepared as 

 just described. On June 8th all the basins in the room showed 



