THE BAVARIAN PROCESS. 349 



evolved during its continuance is not in large bub- 

 bles which burst upon the surface of the liquid, but 

 in small bubbles like those which escape from a 

 liquid saturated by high pressure. The surface of 

 the wort is scarcely covered with a scum, and all 

 the yeast is deposited on the bottom of the vessel 

 in the form of a viscous sediment. 



In order to obtain a clear conception of the great 

 difference between the two kinds of fermentation, it 

 may perhaps be sufficient to recall to mind the fact, 

 that the transformation of gluten or other azotized 

 matters is a process consisting of several stages. 

 The first stage is the conversion of the gluten into 

 insoluble ferment in the interior of the liquid, and 

 as the transformation of the sugar goes on at the 

 same time, carbonic acid and yeast are simultane- 

 ously disengaged. It is known with certainty, that 

 this formation of yeast depends upon oxygen being 

 appropriated by the gluten in the act of decomposi- 

 tion ; but it has not been sufficiently shown, whether 

 this oxygen is derived from the water, sugar, or- 

 from the gluten itself; whether it combines directly 

 with the gluten, or merely with its hydrogen, so as 

 to form water. For the purpose of obtaining a 

 definite idea of the process, we may designate the- 

 first change as the stage of oxidation. This oxida- 

 tion of the gluten, then, and the transposition of the 

 atoms of the sugar into alcohol and carbonic acid, 

 are necessarily attendant on each other, so that if the 

 one is arrested the other must also cease. 



Now, the yeast which rises to the surface of the 

 liquid is not the product of a complete decomposi- 

 tion, but is oxidized gluten, still capable of under- 

 going a new transformation by the transposition of 

 its constituent elements. By virtue of this condition 

 it has the power to excite fermentation in a solution 

 of sugar ; and if the gluten be also present, the 

 decomposing sugar induces its conversion into fresh 

 yeast, so that, in a certain sense, the yeast appears: 

 to reproduce itself. 



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