CHAPTEE X. 



Fermentation. Nature of Ferments. Conversion of Cane Sugar 

 into Alcohol. Setting up Wash. Yield of Alcohol. Dis- 

 tillation. Forms of Stills. 



WHEN cane-juice is allowed to stand for some 

 hours various changes take place. The 

 sugar disappears and a certain quantity of alcohol 

 is found in its place. This change is known as fer- 

 mentation. This term, however, is not limited to 

 the conversion of sugar into alcohol, but is ex- 

 tended to other changes of the most various kinds, 

 e.g., the conversion of alcohol into acetic acid, 

 etc. 



It is now a matter of common knowledge that all 

 these changes which we term fermentation, putre- 

 faction, and decay are due to the life and growth, 

 in the changed substance, of various minute organ- 

 isms, and that if steps be taken to kill those present 

 in a given substance, and to prevent the access of 

 others, even the most easily putrescible substances, 

 such as meat, fish, soup, milk, fruit, and the like, 

 may be kept without change indefinitely. We have 

 commercial examples on an enormous scale of the 

 truth of this, in the various canned foods of all de- 

 scriptions now so abundantly used. These are, for 

 the most part, prepared by closing the food-sub- 



