On July 5th, 1872, we opened and closed twelve flasks similar to those we had used before, the sole difference being that they contained yeast water[47] sweetened with ten per cent. of sugar. One of these flasks furnished us similarly with one kind of _torula_, which bore the greatest resemblance to the ferment of beer. When this _torula_ was beginning to spread all over the bottom of our flask, we shook up the liquid, and turned the flask upside down, with the object of submerging the torula and depriving it of air, at least at the bottom of the neck. For some days, and even months, there were no signs of the liberation of gas. On July 22nd, 1873, after the interval of a year, we opened the flask (which gave no indication of the existence of an interior pressure) and endeavoured to discover the presence of alcohol, by means of successive distillations, as just described. In the two first distillates there seemed to be no alcohol, but in the third we detected its presence in very small quantity. We shall see, later on, that the formation of such a small quantity of alcohol may be attributed to the fact of the plant having been submerged when in full growth, and to its having continued to live for some time after its submersion quite independently of the oxygen contained in the air of the flask. From the previous facts it is obvious that there exist certain productions of various aspects, the germs of which are particularly abundant in the dust of a laboratory where the phenomena of fermentation are studied, productions essentially aerial, and incapable of giving rise to fermentation, although it may be impossible for the microscope to distinguish their forms from those of true alcoholic ferments. The idea of some physiological bond between these plants and the ferments which resemble them in so remarkable a manner, is one that impresses itself forcibly and, so to say, instinctively upon the mind. This remark holds good also in the case of _mycoderma vini_, properly so called, when compared with alcoholic ferments. There appears to be no other difference between the _mycoderma vini_ and the _torulæ_ of which we are speaking, than that afforded by peculiarities of physical structure and a certain greasiness in the cells of the former which permits it to exist, in the form of a scum, upon the surface of liquids, that is to say unsubmerged.[48]