STUDIES ON FERMENTATION. 131 



Between December 20th and 23rd, it ceased altogether to mani- 

 fest itself by liberation of gas. As for the flask B, during all this 

 time it had remained quite inactive and in the same state in 

 which it had existed since June 29th, although the oven had on 

 several days been heated to 28° C. (82° F.). 



On December 23rd, 1872, wishing to assure ourselves of the 

 state of the plant in flask B, we subjected it to the same opera- 

 tion to which the flask C had been subjected on October 20th : 

 that is to say, we poured the contents of the test-glass back into 

 the connected flask, with the object of supplying the plant with 

 oxygen. 



On December 24th, 25th, 26th, 27th, there was no apparent 

 change. 



On December 28th bubbles of gas began to be evolved carrying 

 up clusters of mycelium to the surface of the liquid. It was 

 evident, therefore, that the quiescence in the test-glass attached 

 to flask B, was solely due to deprivation of air, as had happened 

 in the case of the test-glass attached to flask C, up to the date of 

 October 31st. 



On this day, December 28th, we re- decanted the contents of 

 the flask into the test- glass, and the following day a continuous 

 but feeble fermentation proceeded. This lasted until January 

 22nd, although very sluggish in character ; it is evident that 

 these efiects were exactly the same as those which took place in 

 flask C* 



We should observe before we proceed farther, that we took 



* We found, after the lapse of another year, in December, 1873, that 

 the ferment of the mucor in the test glass might still be easily revived ; 

 that it was able to jDropagate, both in the mycelium and in the cellular 

 form, in wort, and that it might produce a fermentation, m.ore or less 

 active, according to the condition of aeration ; in short, that it was 

 capable of producing all the characteristic phenomena described. By 

 means of the method of cultivation that we employ, our study, which was 

 continued for years, was pursued without the least fear of any foreign 

 fungoid growths being introduced into the vessels, although they remained 

 constantly open, and the air in them was being perpetually renewed by 

 the action of diffusion and variations of temperature. In 1875 nothing 

 remained alive in our flask, and further revival became impossible. 



K 2 



