FERMENTATION. 4! 



length in later chapters. Their extreme importance to agri- 

 culture is evident from the list above given. They run all 

 through the agricultural industries, from the preparation of the 

 soil for plants to the production and preparation of the final 

 food products. 



Closely related to the fermentative processes are the 

 phenomena which we call putrefaction and decay. These are 

 also the results of life processes, and cannot be separated from 

 fermentation by any very hard, sharp line. Putrefaction and 

 decay are the results of chemical decompositions which are very 

 complete and more complex and indefinite than the other fer- 

 mentations. Putrefactive changes are commonly regarded as 

 the result of the microorganisms taking certain atoms out 

 of the organic molecules, and these molecules, thus losing 

 some of their atoms, lose their character. The remaining 

 atoms necessarily rearrange themselves to form new com- 

 pounds which are simpler in structure. But putrefactive proc- 

 esses cannot be sharply distinguished from fermentations since 

 many fermentations are apparently also the result of similar 

 decomposition changes. We must therefore class, at least at 

 present, the fermentations and putrefactions together. Putre- 

 factive changes are of an importance in agriculture equal to, 

 if not greater than, the other fermentative processes. Fermen- 

 tation, putrefaction and decay together constitute nature's 

 method of producing the slow organic changes which control 

 the food supply of organisms. 



ORGANIZED AND UNORGANIZED FERMENTS. 



Although differing greatly in their nature and results, all 

 types of fermentation agree in some few points which justify 

 their being placed together as a single class of chemical action 

 differing from ordinary chemical processes. 



1. They are all closely associated with life processes. 



2. They are all closely dependent upon temperature, ceasing 

 4 



