FERMENTATION 273 



of the grape and of the twigs which support the grape. 

 Brush these particles into a capsule of pure water. It is 

 rendered turbid by the dust. Examined by a microscope, 

 some of these minute particles are seen to present the ap- 

 pearance of organized cells. Instead of receiving them in 

 water, let them be brushed into the pure inert juice of the 

 grape. Forty-eight hours after this is done, our familiar 

 Torula is observed budding and sprouting, the growth of 

 the plant being accompanied by all the other signs of ac- 

 tive fermentation. What is the inference to be drawn 

 from this experiment? Obviously that the particles ad- 

 herent to the external surface of the grape include the 

 germs of that life which, after they have been sown in 

 the juice, appears in such profusion. Wine is sometimes 

 objected to on the ground that fermentation is "artificial"; 

 but we notice here the responsibility of nature. The fer- 

 ment of the grape clings like a parasite to the surface of 

 the grape; and the art of the wine-maker from time im- 

 memorial has consisted in bringing and it may be added, 

 ignorantly bringing two things thus closely associated by 

 nature into actual contact with each other. For thousands 

 of years, what has been done consciously by the brewer 

 has been done unconsciously by the wine-grower. The 

 one has sown his leaven just as much as the other. 



Nor is it necessary to impregnate the beer-wort with 

 yeast to provoke fermentation. Abandoned to the con- 

 tact of our common air, it sooner .or later ferments; but 

 the chances are that the produce of that fermentation, in- 

 stead of being agreeable, would be disgusting to the taste. 

 By a rare accident we might get the true alcoholic fer- 

 mentation, but the odds against obtaining it would be 

 enormous. Pure air acting upon a lifeless liquid will 



