STUDIES ON FEKMENTATIOX. 205 



proves, we may observe, by the way, that lactic ferment also 

 can withstand a temperature of 50° C. (122° F.) in the medium 

 which we here employed. The yeast as sowed is represented 

 in Fig. 48 ; it reminds us forcibly of certain forms of the 

 caseous ferment. Amongst the globules, which for the most 

 part were transparent and very young, there were some which 

 appeared aged and of a yellowish colour and granular. These 





Fig. 48. 



latter probably belonged to the yeast of manufacture. Their 

 shape distinguishes them from "high" yeast, properly so 

 called, as on the other hand it causes them to appear more 

 like cells of a recent growth to which, there is no doubt, beer, 

 after it is put in bottle, owes its effervescence and head. These 

 various circumstances incline us to believe that the caseous 

 ferment forms part of certain commercial yeasts, especially 

 those used in the celebrated breweries of Bass and Allsopp, 

 at Burton-on-Trent, in the manufacture of pale ale. Caseous 

 yeast is, moreover, a " high " ferment, that is to say, it rises 

 to the surface. 



§ Y.— On a New Race of Alcoholic Ferments : AiiROBiAN 



Ferments. 



Mention has already been made of certain researches which 

 we undertook with the object of ascertaining whether myco- 

 derma vini, or efflorescence of wine, and mycodenna cereviske, 

 or efflorescence of beer, which grow equally well in all fer- 



