MICROBES, OR BACTERIA. 103 
This ferment may be destroyed by tannin (15 
grammes to a hogshead), which has the effect of pre- 
cipitating it. Very ripe sorbs, which have been crushed, 
may also be used for this purpose, as well as gall- 
nuts and grape-seeds which have been ground to 
powder ; all substances rich in tannin. The precipitate 
thus formed should be separated from the wine by 
refining. 
Wines affected by Bitterness.—This disease affects 
red wines, especialiy those of the choicest vintages 
of Burgundy. Pasteur writes that “at its outset 
the wine assumes a peculiar smell, its colour is ‘less 
vivid, and its taste becomes insipid. Soon the wine 
becomes bitter, and there is a slight taste of fermen- 
tation, due to the presence of carbonic acid gas. 
Finally, the disease becomes more aggravated, the 
colouring matter is completely changed, and the wine 
is no longer drinkable.” 
The microbe which is the essential cause of this 
disease is seen under the microscope in the form of 
articulated filaments, curled back or bent, and it may, 
or may not, be invested with the colouring matter of 
the wine. It is reproduced by fission, not by bud- 
ding. It is probably a bacillus (Fig. 56). 
This ferment must not be confounded with that 
of wine affected by pousse, of which the filaments are 
much moreslender, the articulations are hardly apparent, 
and they are not incrusted with colouring matter. 
Pousse is readily déveloped in wines of inferior quality, 
