STUDIES ON FERMENTATION. 



299 



driven into the bulb / /, until it becomes quite full and the 

 liquid flows over into the glass Y. In this manner we may 



Fig. 71. 



bring the vibrios under observation without their coming into 

 contact with the least trace of air, and with as much success as 

 if the bulb, which takes the place of an object glass, had been 

 plunged into the very centre of the flask. The movements and 

 fissiparous multiplication of the vibrios may thus be seen in 

 all their beauty, and it is indeed a most interesting sight. The 

 movements do not immediately cease when the temperature is 

 suddenly lowered, even to a considerable extent, 15° C. (59° F.) 

 for example ; they are only slackened. Nevertheless, it is 

 better to observe them at the temperatures most favourable to 

 fermentation, even in the oven where the vessels employed in 

 the experin-ent are kept at a temperature between 25° C. and 

 30° C. (77° F. and 86° F.). 



