FEEMEOTATIOK. 81 



withstanding this, when he saw fermentation begin 

 in quite another way, he thought " that the nitroge- 

 nous constituents of the ferment were chemically 

 decomposed, and the decomposition transferred to the 

 sugar by the application of the ferment;" and his 

 view of fermentation, taken as a whole, scarcely differs 

 from that here given, inasmuch as both seek the cause 

 of fermentation, not in the formation, but in the 

 solution of ferment. 



I may just observe, that I do not lay much weight 

 on many of Schubert's early results. It may be as 

 well not to admit that fermentation can be brought 

 about by means of spongy platinum, or oxide of iron. 



H. Eose explains at length why fermentation is 

 promoted by certain organic acids.* He draws atten- 

 tion to the fact, that fermentation is a much slower 

 process in cane than in grape sugar, and that a much 

 larger quantity of ferment is required to produce 

 fermentation in the former than in the latter. If 

 a little tartar is added it quickly sets the cane sugar 

 in fermentation. 



The reason of this is very clear. Eose made use 

 of beer ferment treated with water. The albuminous 

 substance enclosed in the cellules is with difficulty 

 soluble in water, and yet it must escape before fer- 

 mentation can begin. Tartaric acid dissolves it easily, 

 diluted acetic acid with less ease, and sulphuric acid not 

 at all. Eose also found that sulphuric acid and 



* Pogg, Ann. 1841, vol. lii. p. 297. 



G 



