314 FERMENTATION OF SUGAR. 



of saccharic acid, the product of its oxidation. Now 

 none of these atoms of carbon are contained in the 

 sugar as carbonic acid, because the whole quantity is 

 obtained as oxalic acid, when sugar is treated with 

 hypermanganate of potash (Gregory); and as oxalic 

 acid is a lower degree of the oxidation of carbon 

 than carbonic acid, it is impossible to conceive that 

 the lower degree should be produced from the high- 

 er, by means of one of the most powerful agents of 

 oxidation which we possess. 



It can be also proved, that the hydrogen of the 

 sugar does not exist in it in the form of alcohol, for 

 it is converted into water and a kind of carbona- 

 ceous matter, when treated with acids, particularly 

 with such as contain no oxygen ; and this manner 

 of decomposition is never suffered by a compound 

 of alcohol. 



Sugar contains, therefore, neither alcohol nor car- 

 bonic acid, so that these bodies must be produced by 

 a different arrangement of its atoms, and by their 

 union with the elements of water. 



In this metamorphosis of sugar, the elements of 

 the yeast, by contact with which its fermentation 

 was effected, take no appreciable part in the trans- 

 position of the elements of the sugar; for in the 

 products resulting from the action, we find no com- 

 ponent part of this substance. 



We may now study the fermentation of a vegeta- 

 ble juice, which contains not only saccharine matter, 

 but also such substances as albumen and gluten. 

 The juices of parsnips, beet-roots, and onions, are 

 well adapted for this purpose. When such a juice 

 is mixed with yeast at common temperatures, it fer- 

 ments like a solution of sugar. Carbonic acid gas 

 escapes from it with effervescence, and in the liquid, 

 alcohol is found in quantity exactly corresponding to 

 that of the sugar originally contained in the juice. 

 But such a juice undergoes spontaneous decomposi- 

 tion at a temperature of from 95^ to 104^ (35° — 40° 

 C). Gases possessing an offensive smell are evolved 



