BY \{. grer; smith. 315 



subordinate phenomena associated with the disease while the 

 wine is in the cask. The malady shows itself first by an evolution 

 of gaseous carbon dioxide; then the alcohol is converted to acetic 

 acid, and finally a putrefactive fermentation ensues. Many 

 bacteria have been isolated from such wines by various investi- 

 gators from Pasteur in 1865 to Galeazzi in 1894; but in all cases 

 the bacteria either had not been jDurified or experimental evidence 

 as to their infectious nature had not been adduced. In order to 

 produce the various stages, Lafar concludes that a number of 

 organisms are probably necessary. He writes : — "A single bac- 

 terial species is insufficient to occasion the complaint, the successive 

 action of a number of species is essential." 



If we consider the chief phases of the disease, viz., the loss of 

 colour, we find that there appears to be no reason why it might 

 not be caused by the action of an acetic organism. In an allied 

 disease, the browning of white wine, "^a casse,^' the wine when 

 poured from the cask into a glass vessel becomes darker in colour, 

 especially in the upper layers. The colour spreads downwards, 

 the wine becomes turbid, and finally a fine dark powder is 

 deposited. The formation of a deposit is similar to what occurs 

 in " vi7i tour7ie" and doubtless it was this that caused the loss of 

 colour of red wine to be for a long time classed with the browning 

 of white wine. In the latter disease it is at present accepted 

 that the phenomenon is caused by an enzyme, which plays the 

 part of a carrier of oxygen, that is, an oxidase. The oxygen of 

 the air is absorbed by it and given up to the colouring matter and 

 tannins of the wine, which are converted into insoluble and dark- 

 coloured compounds. 



Since it is admitted"^ that an oxidase causes the formation of a 

 dark powdery deposit in the case of " vi^i casse','^ there appears 

 to be no reason why an oxidase should not also be responsible for 

 the similar formation of a dark powdery deposit in the loss-of- 

 colour stage of " vin tourne." It is true that in the one case 

 an oxidase has been isolated and not in the other, but that may 



* Lafar, op, cit., 400. 



