70 STUDIES ON FERMENTATION. 



Avater and then cooled, necks downwards. The beak of the 

 basin, b}' means of which the liquid vras poured, and the 

 funnels — for we used a separate funnel for each flask — had been 

 passed through the flame. The whole ten flasks were then 

 placed in an oven at a temperature of 25° C. (77° F.).* 



On June 1st six of the flasks gave signs of fermentation, and 

 next day all the flasks were fermenting. 



The following are some of the numerous microscopic observa- 

 tions which we made on the liquids and their deposits. 



On June ] st the liquid in one of the six flasks which had 

 begun to ferment was covered with a continuous scum of nvjco- 

 dcrma vim, below which appeared a filamentous network belong- 

 ing to a mycelium, or other fungoid growth. But neither in the 

 liquid itself nor in the deposit could we perceive any cells of the 

 ferment of beer; the field, however, was swarming with active 

 butyric vibrios, rather thick and short, their length being 

 about twice their diameter. This fermentation was exclusively 

 butyric. 



On June 2nd another of the flasks showed no vibrios, but 

 alcoholic ferment in small quantity, much lactic ferment, con- 

 sisting of little particles contracted at the middle and non- 

 mobile, and, finally, some slender filaments, resembling those 

 represented in Plate I., Nos. 1 and 2. 



On June 3rd we examined the liquid in the flask which 

 showed the most marked fermentation. In addition to the 

 flakes of fungoid growths, checked in their development through 

 ■want of air, we found at least five distinct productions, which 

 are represented in the accompanying sketch (Fig. 1]). 

 aaa. — Thick cells of alcoholic ferment, the size of which is given 

 in our sketch : thus, -^^-f-^ indicates that the correspond- 

 ing figure is ^^'-V millimetre in length (rather more than 

 -oinr inch). 

 hbb. —Small alcoholic ferment, such as we generally see in the 



* The decanting into the flasks is necessary, because of the possibility 

 of the fermentation in the basins being masked . See further on the note 

 on p. 75. 



