68 STUDIES ON FERMENTATION. 



musts may be made to ferment, by being rapidly brought 

 into contact with the surrounding air, is greatly exagge- 

 rated. 



The germs of ferments, especially of alcoholic ferments — the 

 yeast of beer and the yeast of wine — are not nearly as 

 abundant in atmospheric air, or in the particles of dust spread 

 over the surface of things, as are the spores of fungoid growths. 

 It is easy to understand this, for spores are generally borne 

 by aerial organs in a state of dryness, so that the least breath 

 of wind catches them up and carries them away, whilst 

 ferments are composed of moist cellules that do not readily 

 become dry. 



The vacuous flasks, partly filled witli organic liquids, which 

 are opened and closed again immediately, frequently give us 

 fungoid growths, but very rarely alcoholic fermentation, although 

 in the latter respect they may not be absolutely sterile. "We 

 may cite some proofs of this. 



On June 19th, 1872, we prepared seven flasks of saccharine 

 liquid, impregnated with yeast — our flasks were of 300 c.c. 

 capacity (about 10 fl. oz.) — and contained 100 c.c. of the 

 liquid ; we then drew out their necks to a small opening, which 

 was sealed during boiling, after the steam had expelled all the 

 air. 



On June 29th we opened them in the principal room of 

 our laborator3\ 



On July 9th, two of the seven flasks gave no sign of organized 

 products ; the others were swarming with mycelia, submerged 

 or fruiting on the surface of the liquid, and either with or 

 without bacteria entangled in their flakes. In two of the flasks 

 there were visible at the bottom of the liquid some white streaks, 

 which is an indication sometimes of the presence of alcoholic 

 ferment, but much more frequently of a little cellular plant 

 resembling it in appearance, but purely aerial in its growth, 

 that is to say, taking no part in fermentation. Some days 

 afterward, we saw bubbles of gas rising from the bottom of 

 one of these flasks, and then fermentation proceeded so rapidly 



