STUDIES ON FERMENTATION. 67 



placed on an oven, where there were always vessels fermenting, 

 at about 25° C. (77° F.), but where none of the manipulations 

 required for the starting or final study of fermentations were 

 practised. The next day a fungoid growth, but unaccompanied 

 by any signs of fermentation, made its appearance, and this 

 state of things lasted for five months, after which we ceased 

 to keep these bottles under observation. 



On May 26th, 1873, we uncorked, with all the necessary pre- 

 cautions, ten bottles of wort, which had been preserved from 

 April 9th, and then left them undisturbed in a room where we 

 were constantly engaged in the study of fermentation. 



On the following day, some patches of fungoid growth ap- 

 peared on the surface of the liquids. 



May 30th. — Fermentation commenced in one of the bottles. 



May 31st. — A second bottle likewise began to ferment. 



June 9th. — Four bottles, including the two preceding ones, 

 were now in a state of fermentation. The six bottles that had 

 not fermented were thereupon covered with caps of paper, taken 

 from the centre of a ream of paper and passed through a flame. 

 After this, and up to August 1, when our observations were 

 discontinued, these six bottles underwent no fermentation. 



From these examples, which are confirmed by many others 

 that we shall have occasion to mention in the course of this 

 work, it will be seen that the germs of alcoholic ferment are not 

 present in every little point of space, constantly ready to fall 

 upon any object, not even in those places M^here one is per- 

 petually dealing with that kind of growth.* If we conduct 

 our experiments with exactness^ we very soon learn that all 

 that has been written on the facility with which saccharine 



* It has already been observed in our Memoir on spontaneous genera- 

 tion, that alcoholic fermentation is not always to be obtained by sowing 

 wads of cotton or asbestos, charged with the particles of dust which float 

 through the air, in saccharine musts that are in contact with much air. 

 The air which furnished the particles of dust, in the experiments to 

 which we are alluding, was taken outside the laboratory, in a neighbouring 

 street. 



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