182 



and new substances are formed, differing much in their physical, as 

 \vell as their chemical properties, from the substance from which 

 they have proceeded. One particular point in which they almost 

 always differ may be here very properly noticed. The combina- 

 tions resulting from these spontaneous changes, occasioned by 

 the intestine motions of the constituent principles, regularly pro- 

 duce substances less' compounded than those which these prin- 

 ciples previously formed. Before the final change, however, is 

 completed, certain regular periods in the process must be passed 

 through ; and the substance exposed to the operation must necess^ 

 arily exist in several intermediate states. In passing through these 

 different states it acquires new and peculiar characters ; and may 

 be arrested in any one of these stages of transformation, and so 

 fixed, that it shall pass on to no further change. 



Between the phenomena of fermentation in general, and those 

 which accompany that which I term the bituminous fermentation, 

 I trust you will perceive a total agreement, when the latter are 

 more particularly examined. But that this may more clearly ap- 

 pear, I will proceed to take a more particular view of the effects of 

 this process, with those proceeding from the other species of vege- 

 table fermentation. 



Vegetable matter, then, I consider as subject to five different 

 species of fermentation, each of which appears to be, in a great 

 measure, dependent on the degree to which the access of air and 

 water is admitted. 



The saccharine fermentation takes place in those parts of vege- 

 tables in which the saccharine principle seems to be present, and 

 merely to require evolution, as in the roots of the parsnip, beet, &c. 

 the monocotyledon seeds, &c. This principle acquires a saccharine 

 form merely by the attraction of oxygen from the atmosphere, 

 d uring the germination of these seeds ; in which state it is pre- 

 erve d by the common operation of malting. From other parts of 



