STUDIES ON FERMENTATION. 107 



formed of aged, granulated filaments, with few swellings. The 

 weight of the dry fungoid growth was 050 gramme (about 8 

 grains) for a total volume of liquid of 122 c.c. (4^ fluid ounces). 

 "We obtained 4*4 c.c. of alcohol of 15°, which was about seven times 

 the weight of the plant. Finallj^, 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 forma- 

 tion of an organic acid, the nature of which it would be interest- 

 ing to determine. M. Gay on 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 difiering 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 con- 

 siderable 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.) 

 v>^e found : — 



Growth in the aerated flask . . 0*92 



Growth in the closed flask . . 0"16 



Ratio of weights, f| = 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 

 save 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 demon- 

 strate once more, in the most conclusive manner : — 



