% 308 SUBSTANCES EOTJND TO POSSESS 



It is well known that such chemical operations as 

 are speedily brought about by means of heat, or other 

 agents, may be effected more slowly without such 

 assistance. Liebig* dissolved oxalic acid in alcohol 

 by heat till it was saturated, and left it standing at a 

 temperature of from 40 to 50 (104 to 122 F.) After 

 it had stood for some months he found oxalic ether 

 and oxalo-vinic acid in it. 



Hippuric acid forms hippuric ether in the same 

 manner. But benzoic acid requires a much longer 

 time before any ether is formed from it. 



Tartaric acid has the power of forming rapidly, 

 when in contact with alcohol, without the assistance 

 of heat or any other body, etherised tartaric acid. 



This is the first point we have to consider, in order 

 to obtain a clear idea of the origin of the substances 

 existing in wine. Free tartaric acid is contained in 

 grape-juice. As soon, therefore, as alcohol is formed 

 out of sugar, etherised tartaric acid will also be pro- 

 duced, and remain dissolved in the wine. This body is 

 destitute of odour, and cannot, therefore, impart any 

 fragrance to the wine. Its taste, however, being much 

 less sharp than tartaric acid, may render the wine 

 sweeter, without causing any actual increase of sugar, 

 which indeed can hardly be assumed after the wine has 

 been bottled (p. 113). Etherised tartaric acid is easily 

 decomposed, and when the watery solution is kept 

 it resolves itself again into tartaric acid and alcohol. 



* Ann. der Ch. u. Pharmacie. 



