A VINOUS SMELL. 325 



liquid then allowed to ferment, a scentless wine is 

 obtained. 



If grape juice be evaporated, the residue mixed 

 again with water, and allowed to ferment, a wine with- 

 out aroma is obtained. 



If grape juice be mixed with olive oil, and the juice 

 fermented after the oil is separated from it, a wine 

 without bouquet is again obtained.* 



There are vegetables which contain sugar and 

 ferment, but during fermentation yield no alcohol, as, 

 for example, onions. If they do furnish alcohol, the 

 amount is not in proportion to the quantity of sugar 

 contained in them. Eraconnotf first examined this 

 subject, and found mannite, vegetable mucus, and 

 lactic acid among the products of fermentation. 

 Kirchner found that the composition of the mucilagi- 

 nous substances discovered by Braconnot and of gum 

 was the same ; and Pelouze, Jules G-ay-Lussac, and 

 others, have examined these products in detail. Pelouze 

 found that hydrogen gas was evolved during the fer- 

 mentation of these vegetables, but it is often wanting, 

 and does not appear to belong necessarily to this 

 fermentation, which is called mucous fermentation, 

 because the formation of vegetable mucus generally 

 renders the liquid thick (p. 127). 



The mannite which is thus formed from sugar is 

 C 6 H 7 O 6 , the lactic acid and the gum have the corn- 



* Schubert. Techn. Chemie, Erlangen, 1854, s. 352. 

 t Ann. de Chemie, torn. Ixxxvi. p. 97. 



