FERMENTATION AND PUTREFACTION. 299 



kind of decomposition, which we have named trans- 

 formations : the elements of the bodies capable of 

 undergoing these changes arrange themselves into 

 new combinations, in which the constituents of water 

 generally take a part. 



Eremacaiisis (or decay) differs from fermentation 

 and putrefaction, inasmuch as it cannot take place 

 without the access of air, the oxygen of which is 

 absorbed by the decaying bodies. Hence, it is a 

 process of slow combustion, in which heat is uni- 

 formly evolved, and occasionally even light. In the 

 processes of decomposition termed fermentation and 

 putrefaction, gaseous products are very frequently 

 formed, which are either inodorous, or possess a very 

 offensive smell. 



The transformations of those matters which evolve 

 gaseous products without odor, are now, by pretty 

 general consent, designated by the term fermenta- 

 tion ; whilst to the spontaneous decomposition of 

 bodies which emit gases of a disagreeable smell, the 

 term putrefaction is applied. But the smell is of 

 course no distinctive character of the nature of the 

 decomposition, for both fermentation and putrefac- 

 tion are processes of decomposition of a similar kind, 

 the one of substances destitute of nitrogen, the oth- 

 er of substances which contain it. 



It has also been customary to distinguish from 

 fermentation and putrefaction a particular class of 

 transformations, viz., those in which conversions and 

 transpositions are effected without the evolution of 

 gaseous products. But the conditions under which 

 the products of the decomposition present them- 

 selves are purely accidental ; there is, therefore, no 

 reason for the distinction just mentioned. 



