The total volume of liquid, which was 130 c.c., (4·57 fl. oz.) contained 2·3 grammes (35·3 grains) of alcohol. In spite of this rather large proportion of alcohol, a clear sign of undoubted fermentation, the plant had yielded no _conidia_ at all, nor any cell-globules of ferment. Some of the filaments, however, were larger than the rest, and exhibited irregularly-shaped swellings, which in some cases were of enormous size. Whilst the natural mycelial filaments, by which we mean the vegetating part of mucor, which were supplied with abundance of air, only measured 3/450 of a millimetre[81] in diameter, the filaments that had grown probably with an insufficiency of oxygen, and performed the functions of ferment, measured 8/450, and the swellings as much as 30/450 of a millimetre in diameter, as represented in Fig. 24. [Illustration: Fig. 24.] In concluding this paragraph, we may mention a very able research on fermentation which we have lately studied, the author of which, Dr. Fitz, communicated it to the Chemical Society of Berlin in 1873. In section II., page 48, this author explains his observations in a manner conformable to our own views, as may be seen from the following passage of the memoir:— “In the presence of oxygen, the ferment of _mucor_ develops into a mycelium and consumes the sugar; in the absence of oxygen, on the other hand, the spores develop into ferment of _mucor_, that buds and decomposes the sugar into the products of fermentation. “The properties of _mucor mucedo_ in a fermentable liquid, in the presence or in the absence of oxygen, accord perfectly with the theory of fermentation established by Pasteur in 1861 (_Comptes rendus de l’Académie des Sciences_, t. lii., p. 1260). According to this theory a fermentative fungus needs oxygen for its development; if it finds any free oxygen it utilizes the whole of it, assimilating one part of the sugar and burning the other; whilst in the absence of free oxygen, the fungus appropriates what it requires from the sugar.” Footnote 49: