On December 16th, 1872, we uncorked four bottles of wort, which also had been preserved by Appert’s process; these we 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 precautions, 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 appeared 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 where one is perpetually dealing with that kind of growth.[41] If we conduct our experiments with exactness, we very soon learn that all that has been written on the facility with which saccharine musts may be made to ferment, by being rapidly brought into contact with the surrounding air, is greatly exaggerated. 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 with 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.