156 



STUDIES ON FERMENTATION. 



It may be asked, wliat proof have we that amongst the 

 filamentous and cellular growths which spring from the small, 

 dark bodies existing in the particles of dust adhering to the sur- 

 face of fruits, and which we here see bud and multiply with 

 such marvellous rapidity, the ferment or ferments of vintage do 

 actually exist ? A very simple experiment will prove conclu- 

 sivel}' that this is the case. When in the course of twenty-four 

 or forty-eight hours, by contact with saccharine must, and in 

 presence of excess of air, the revival and development of the 

 cells has taken place on the bottom of the little troughs 

 employed in our observations ; if then we fill up the trough with 

 the same must, so that there remains no free air under the 

 cover-glass, within a very short time — an hour, half-an-hour, or 

 often less — we shall see bubbles of gas rise from the bottom, 

 accompanied by an increase in the deposit of cells. This will be 



bulb, the sides of which, in the centre, come sufficiently close together 

 to enclose but a verj^ thin layer of liquid, and to admit of microscopical 



Fig. 31. 



examination. We may fill these tubo-bulbs completely with liquid, to 

 the exclusion of air or we may surround the central drop with air. 



