On December 12th, 1874, we examined the liquid and the plant, which for a long time had appeared dead. Its mycelium was formed of aged, granulated filaments, with few swellings. The weight of the dry fungoid growth was 0·50 gramme (about 8 grains) for a total volume of liquid of 122 c.c. (4-1/4 fluid ounces). We obtained 4·4 c.c. of alcohol of 15°, which was about seven times the weight of the plant. Finally, we determined the acidity of the liquid, and found 2·8 grammes, in equivalents of sulphuric acid, a quantity greatly in excess of the total acidity of an equal volume of wort, a fact which shows us that fermentation caused by _aspergillus glaucus_ is accompanied by the formation of an organic acid, the nature of which it would be interesting to determine. M. Gayon has commenced the study of this subject in our laboratory. In concluding our observations on the _aspergillus glaucus_, we may give the comparative results of two growths that were obtained under precisely similar conditions, in flasks of exactly the same size, but differing in this respect—that one of them was constantly subjected to a current of pure air that played on the liquid. In the course of a few days, when the fungoid growth in the flask that had been aerated had attained a considerable size, in comparison with the other, we broke the flasks in order that we might take out the two growths and compare their weights. After drying them at 100° C. (212° F.) we found:— Growth in the aerated flask 0·92 Growth in the closed flask 0·16 Ratio of weights, 92/16 = 5·75. Again, although we had taken the precaution of condensing in a U tube, over which cold water played, the vapours carried away by the current of air, the liquid in the aerated flask gave no evidence of alcohol. That in the other flask contained a very appreciable quantity, although the weight of fungoid growth in that flask was scarcely a sixth part of what it was in the other. The preceding facts taken altogether, seem to us to demonstrate once more, in the most conclusive manner:— Firstly, That neither _penicillium_ nor _aspergillus glaucus_ can change into yeast, even under conditions that are most favourable to the life of that ferment. Secondly, That a fungoid growth which vegetates by using the oxygen of the air, and which derives from the oxidating action of that gas, the heat that it requires to enable it to perform the acts necessary to its nutrition, may continue to live, although with difficulty, in the absence of oxygen; that, in such a case, the forms of its mycelian or sporic vegetation undergo a change, the plant, at the same time, evincing a great tendency to act as alcoholic ferment, that is to say, decomposing sugar and forming carbonic acid gas, alcohol, and other substances which we have not determined, and which probably vary with different growths.