MICROBES, OR BACTERIA. 



99 



This product does not turn the wine sour, nor sensibly 

 affect it. It is due to the temperature of the casks 

 being too high during the hot season. It may be 

 obviated by sprinkling them with cold water, or by 

 putting ice into them; care must also be taken to 

 keep the casks full, and the cellars as cool as possible. 

 Acidity of Wines ; Soured Wines. Wine always 



Fig. 53. The disease acescence, which sours wine. Deposit seen in the microscope ; 

 1, 1, Mycoderma vim; 2, 2, Mycoderma, aceti, still young; 3, the same older, when 

 the mischief is at an advanced stage. 



contains a small quantity of acetic acid, and when 

 this acid is in excess, the wine is no longer drinkable, 

 and turns to vinegar. This change is due to the 

 presence of Mycoderma aceti (Fig. 53), of which we 

 have already spoken. It is much more minute than 

 'M. vini, and takes the form of the figure 8, as the 

 illustration shows, or of chaplets formed by the union 



