OILY AND ETHEREAL PRODUCTS. 289 



this property, still it diminishes, in a great de- 

 gree, the influence of decomposing azotised bodies 

 upon the conversion of alcohol into acetic acid. 

 There is, therefore, reason to believe that some aro- 

 matic substances, when added to fermenting mix- 

 tures, are capable of producing very various modi- 

 fications in the nature of the products generated. 



Whatever opinion, however, may be held regard- 

 ing the origin of the volatile odoriferous substances 

 obtained in the fermentation of wine, it is quite 

 certain that the characteristic smell of wine is 

 owing to an ether of an organic acid, resembling 

 one of the fatty acids. 



It is only in liquids which contain other very 

 soluble acids, that the fatty acids and cenanthic 

 acid are capable of entering into combination with 

 the ether of alcohol, and of thus producing com- 

 pounds of a peculiar smell. This ether is found in 

 all wines which contain free acid, and is absent 

 from those in which no acids are present. This 

 acid, therefore, is the means by which the smell is 

 produced ; since without its presence cenanthic ether 

 could not be formed. 



The greatest part of the oil of brandy made from 

 corn consists of a fatty acid not converted into 

 ether; it dissolves oxide of copper and metallic 

 oxides in general, and combines with the alkalies. 



The principal constituent of this oil is an acid 

 identical in composition with cenanthic acid, but 

 different in properties. (Mulder.) It is formed in 



u 



