FERMENTATION. 5 I 



living, as some do, cannot be determined. In short we have 

 in the enzymes substances as mysterious as the original fer- 

 mentation. In explaining fermentations upon the ground of 

 the formation of enzymes we must not, then, imagine that we 

 are really explaining them. We are getting a little closer idea 

 of the details of the process, but are not brought any closer 

 to an actual knowledge of the fundamental nature of the fermen- 

 tative process. 



All of these types of fermentations, whether caused by the 

 metabolism of bacteria or yeasts, or by enzymes, secreted by 

 these organisms or by higher plants, are of vital importance 

 in agricultural processes. Without their agency in breaking 

 up organic compounds the soil would rapidly become unfit for 

 supporting life. The agricultural industry is therefore not only 

 dependent upon fermentations for many minor processes, but 

 is fundamentally dependent upon them for its continuance. 

 While this is true it must not be assumed that the various bac- 

 teria produce their results for the benefit of agriculture or for 

 the benefit of the soil. There is no purpose in the matter. 

 Each species acts its own life for its own good. If it secretes 

 an enzyme that produces a fermentation, this is done for its 

 own benefit and not for the farmer's. Incidentally it may re- 

 sult that the natural processes of life phenomena are benefited 

 thereby, but primarily all of the enzymes secreted, and all of the 

 fermentations produced, are for the benefit of the organisms 

 themselves. If a bacterium secretes an enzyme into a lot of 

 milk which causes its digestion, its purpose is to digest the 

 milk for its own use and not for any incidental results that 

 may accrue to agriculture. 



LIST OF REFERENCES. 



It is impossible to give a complete list of references of the immense literature 

 covered by the subjects considered in this work. In the brief list at the end of 

 each part of the book it is the endeavor to give a few of the important papers 

 covering the topics considered, especial attention being given to recent literature. 



