102 STUDIES ON FERMENTATION. 



was on the surface of the liquid, in the neck of the flask, was 

 studded with bubbles of gas ; these we dispersed by shaking. 

 On June 22nd, many others had formed again, and a large flake 

 of mycelium that had risen from the bottom of the test flask 

 had been stopped at the bottom of the neck, quite distended by 

 gas bubbles. We liberated the gas b}^ shaking, but the bubbles 

 formed again by the next day, and this effect continued for 

 several days ; nevertheless the liberation of gas was not con- 

 tinuous, as is the case in an ordinary fermentation. 



On July 20th we drew off the liquid and distilled it ; it was 

 still very sweet, but though it contained a sensible quantity of 

 alcohol, the microscope failed to detect a single cell of ordinary 

 alcoholic ferment. 



These results show that the aspergilliis when in full growth, 

 with plenty of air at its disposal, does not yield alcohol, and that 

 if we submerge it, so as to prevent the oxygen of the air from 

 readily coming into contact with its various parts, it decomposes 

 sugar, after the manner of yeast, forming carbonic acid gas 

 and alcohol. 



These effects were still more marked in the case of the flask 

 C, the liquid in which, after having been shaken up, was not 

 decanted to any great depth in our test flask, as had been the 

 case with B. From June 21st, there was mycelium on the surface 

 of the liquid, studded with large bubbles of gas, which formed 

 again after having been liberated by shaking. This last flask 

 was examined on November 1st, 1873. Its aspect was un- 

 changed ; the liquid was covered with mycelium loaded with 

 sporanges and borne up by large old bubbles that had not 

 disappeared. The following was the analj'sis of the liquid : — 



Alcohol 1-2 



Glucose . . .. .. •• 84"0 



Dextrine (?) 320 



The liquid was very bright, and contained an amorphous 

 granular deposit, formed by the wort after it had been boiled, 

 at the time when we prepared our flasks. We crushed a small 



