STUDIES ON FERMENTATION. 217 



aerobian ferment, as taken on November 27tli, 1873, from a 

 pellicle of rather greasy and moist appearance, on the surface 

 of a flask of fermented beer-wort which had been impreg- 

 nated on July 21st, 1872. It might readily be mistaken for 

 ordinary ** high " j^east, yet no two ferments can be more 

 distinct. 



On November 27th, 1873, we sowed a trace of this ferment 

 in a flask of wort. From the 29th, with a continuous tem- 

 perature of 25° C. (77° F,), a considerable deposit of yeast 

 began to form, and the froth of fermentation covered the whole 



|i« %© jm ^ 





Fig. bb. 



surface of the liquid. We took a little of this deposit for 

 examination ; it is represented in Fig. 56. The field is 





Fig. b^. 



occupied with oval cells of great uniformity. We recognize 

 the aspect of the original yeast (Fig. 43), Here and there, 

 indeed, we come across some cells of larger size, such as those 

 at a and h, which is another illustration of the remark that we 

 have just made respecting the forms which revived exhausted 

 cells take on at the commencement of a new germination. 



