Fabroni has shewn that the gluten in must is 

 essential to fermentation ; and that chemist has made 

 saccharine matter ferment, by adding to its solution 

 in water, common vegetable gluten and tartaric acid. 

 Gay Lussac has demonstrated that must will not fer- 

 ment when freed from air by boiling, and placed out 

 of the contact of oxygene , but that fermentation be- 

 gins as soon as it is exposed to the oxygene of air, a 

 little of that principle being absorbed ; and that it then 

 continues independent of the presence of the atmos- 

 phere. 



In the manufacture of ale and porter, the sugar 

 formed during the germination of barley is made to 

 ferment by dissolving it in water with a little yeast, 

 which contains gluten in the state proper for produc- 

 ing fermentation, and exposing it to the requisite tern- 

 perature ; carbonic acid gas is given off as in the 

 fermentation of must, and the liquor gradually be- 

 comes spirituous. 



Similar phenomena occur in the fermentation of 

 the sugar in the juice of apples, and other ripe fruits. 

 It appears that fermentation depends entirely upon a 

 new arrangement of the elements of sugar ; part of 

 the carbon uniting to oxygene to form carbonic acid, 

 and the remaining carbon, hydrogene, and oxygene 

 combining as alcohol ; and the use of the gluten or 

 yeast, and the primary exposure to air seems to be to 

 occasion the formation of a certain quantity of car- 

 bonic acid ; and this change being once produced is 

 continued ; its agency may be compared to that of a 

 spark in producing the inflammation of gunpowder ; 



