DISEASES OF WINE. 127 



But if it spreads, colour, flavour, and aroma are for 

 ever gone, and the wine can be used only for distilling 

 brandy : and it may proceed so far as to convert 

 the alcohol into acetic acid, in which case putrid 

 fermentation sets in. 



THE ROPIKESS OF WINE. 



This disease consists in the formation of vegetable 

 mucus, C 24 H 19 O 19 , from the sugar of the wine, 

 C 24 H 24 O 24 , water being at the same time separated. 

 Vauquelin made this discovery.* He received some 

 bottles filled with the juice of the sugar-cane from 

 Martinique. The juice was put into the bottles in 

 the manner described by Appert ; it was heated for a 

 few minutes at a temperature of 100 C. (212 !\), and 

 the bottles closed. The sugar was almost entirely 

 converted into a tough mass, part of which had been 

 deposited from the liquid, and was, therefore, not 

 gum, and another portion was still dissolved. This 

 flowed so slowly, that it could hardly be poured out 

 of the bottle. 



The same transformation may be remarked in beet- 

 root, and in the juice of the carrot, onion, and many 

 other plants ; if they are exposed to a temperature of 

 from 30 (86 E.) to 40 (104 F.), an escape of car- 

 bonic acid may be observed. Cane sugar is trans- 



* Ann. de Ch. et de Phys. tome xx. p. 93. 



