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 vini; 2,2, Mucoderma 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 alréady 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 
