258 THE FERMENTATION OF UREA 



Unfortunately, pure cultures were not employed in this research, which was 

 published in 1890, and the same defect attaches to an investigation made by 

 E. GERARD (I.) in 1896. 



In a chemical sense, the statement just recorded was confirmed by the 

 treatise of Burri and his co-workers, mentioned in 187. These workers also 

 included the decomposition of hippuric acid in the scope of their labours. Like 

 their Italian colleagues, however, they did not employ pure cultures of ferments, 

 but used " a drop of manure drainings" for inoculating the media. They found 

 that hippuric acid was not attacked per se, but only when in combination with 

 lime, the decomposition, moreover, being more difficult to effect than was the 

 case with uric acid or urea which last named is the easiest of all to convei't into 

 ammonium carbonate. Both for the sake of completeness and also to show the 

 necessity for a more accurate investigation of the decomposition of hippuric acid, 

 we must refer to a remark made by Van Tieghem in his above-mentioned 

 treatise, namely, that his B. iirece is capable of splitting up hippuric acid into its 

 two components, glycocoll and benzoic acid, according to the equation 



CH 2 . NH CO CH . NH Q COOH 



I I + H 2 = | +| 



COOH C 6 H 5 COOH C 6 H 5 



Analytical data to prove that this decomposition actually goes on so smoothly 

 are, however, lacking. 



So far as the destiny of hippuric acid in the soil is concerned, K. YOSHIMURA 

 (I.) has observed that its fermentation proceeds much more rapidly in the upper 

 layers than in the subsoil. 



