Chap. 6.] [ 6 1 ] 



CHAP. Vt. 



FERMENTATION. 



Kinds of Fermentation. The vinous or fpirituous. Spirit of 

 Wine or Alcohol. ~Etber, Acetous Fermentation. Putrid Fermen- 

 tation.-Obfer-vations on Putrefaflion in general. 



HAVING confidered the ftructure and compo- 

 fition of vegetable fubftances, it becomes ne- 

 ceflary to direct our attention to certain fpontaneous 

 changes which they undergo, when deprived of the vi- 

 tal principle. Thefe changes are called fermentations, 

 which are three in number, and are termed, from their 

 products, the vinous or fpirituous, the acetous, and the 

 putrid. The circumftances univerfally neceflary to fer- 

 mentation are moifture, a certain degree of heat, and 

 the contact of air. The three kinds of fermentation 

 are Ibmetimes confidered as different flages of one pro- 

 cefs i this, however, is an improper view of the fubjeft, 

 as each kind of fermentation is a peculiar procefs, and 

 totally different from every other. Some bodies be- 

 come acid without having undergone the fpirituous fer- 

 mentation, and others putrify without fhewing any dif- 

 pofition to afTume either that or the acetous ftate. 



The conditions neceflary for the production of the 

 VINOUS or fpirituous fermentation are i. A degree 

 of fluidity flightly vifcid. 2. The prefence of laccha- 

 rine mucilage. It is found that the fermentable juices 

 of fruits, boiled till they become thick, are indifpofed 

 to ferment, and this not only in their infpiflated ftate, 

 but when diluted again with water : for this reafon it 

 is, that in the making of fugar nothing is of more im- 

 portance than the juice of the cane being fubmitted to 



boiling 



