84 . AGRICULTURAL BACTERIOLOGY. 



shown here, as elsewhere, the presence of a number of distinct 

 species with this characteristic, which are almost sure to be in 

 urine ready to accomplish its fermentation (Fig. 14). The re- 



FIG. 14. 



Various bacteria causing the ammoniacal fermentation of urea. (Beijerinck.) 



suit of the fermentation is that the urea is split up according 

 to the following equation : 



COH 4 N 2 -f 2lI 2 O = CO 2 + 2NH ? + H 2 O = (NH 4 ) 2 CO 3 



(urea) (ammonia) 



A similar ammoniacal fermentation occurs in the destruction 

 of other nitrogenous organic bodies. Proteids almost always 

 show the presence of ammonia while undergoing putrefaction 

 and, indeed, the ammoniacal fermentation is one of the most 

 widely occurring types of the chemical destruction of organic 

 bodies. The exact details of the chemical change will rarely 

 be so simple as that given above for the fermentation of urea. 

 Since other organic bodies contain other chemical elements in 



