FERMENTATION AND PUTREFACTION 83 



DC. FERMENTATION AND PUTREFACTION. 



The terms "fermentation" and "putrefaction" have been confused 

 and even used synonymously in bacteriological, chemical and even 

 legal nomenclature, but they represent essentially distinct and generic 

 types of bacterial activity. They indicate, or should indicate 

 respectively, microbic decomposition of two quite distinct types of 

 organic compounds, the carbohydrates and closely related nitrogen- 

 free compounds, on the one hand (fermentation), and nitrogenous 

 organic substances on the other hand, putrefaction. There are 

 substances intermediate in character between carbohydrates and 

 proteins, or fats and nitrogen-containing compounds in which it 

 would be difficult to predict a priori which term would be correct 

 glucose amine is such a substance. Glucose amine is an amino- 

 aldose, containing both nitrogen and carbohydrate groupings. Such 

 instances, however, are uncommon and do not militate against the 

 correctness of the general theory that fermentation and putrefaction 

 are distinct processes. 1 



Fischer 2 has defined fermentation in the broad sense it should be 

 used in bacteriology, essentially in the following terms: "Fermenta- 

 tion is the biochemical decomposition of nitrogen-free compounds, 

 chiefly carbohydrates, by the action of microorganisms." Similarly, 

 putrefaction is defined as "The biochemical decomposition of nitro- 

 genous organic compounds by the action of microorganisms." 



Fermentation and putrefaction are probably enzyme phenomena. 



Transposing the sparing action of utilizable carbohydrate for 

 protein, which has been repeatedly emphasized in the preceding 

 pages, it may be stated that in the catabolic phase of bacterial metab- 

 olism "fermentation takes" precedence over putrefaction," 3 meaning 

 by that that bacteria which can utilize carbohydrate derive their 

 energy requirements from the utilizable carbohydrate when they are 

 growing in media containing both carbohydrate and protein. The 

 results of this sparing action of utilizable carbohydrate for protein 

 have been indicated in the preceding pages, sections V-VIII, inclusive. 



1 Kendall, Jour. Med. Research, 1911, N. S., xx, 140-144. 



2 Vorlesungen iiber Bakterien, 1903, II Aufl., 206. 



3 Kendall, Jour. Med. Research, 1911, N. S., xx, 140-144. 



