HIPPURIC ACID FORMATION IN HERBIVORA 109 



stated, "that the synthesis of hippuric acid in rabbits not 

 only occurs in different organs but also in a different chem- 

 ical manner than in dogs." 



Hippuric Acid Elimination in Carnivora and in Man. 

 In carnivora, from the classical perfusion studies of Bunge 

 and Schmiedeberg, the kidney is the sole seat of hip- 

 puric acid synthesis. It should here be recalled, however, 

 that according to Schmiedeberg the kidney contains a fer- 

 ment, histozyme, which is capable of splitting hippuric acid 

 into benzoic acid and glycocoll, 29 which may be identical with 

 the ferment synthesizing the hippuric acid, as we have come 

 to recognize a number of examples of the reversibility of 

 enzyme action. Generally speaking the phenomena in the 

 carnivora present nothing surprising. If the living animal 

 be flooded with benzoic acid a large part is passed uncom- 

 bined ; a portion unites with some otherwise unknown reduc- 

 ing substance ; and that part which appears in the urine as 

 hippuric acid is not so great that it cannot be explained by 

 the amount of glycocoll preexisting in the protein molecule 

 and separable by hydrolysis from the dietary and tissue 

 protein. 30 (This amount of glycocoll corresponds to only 

 4 to 5 per cent, of the total nitrogen mobilized in protein 

 catabolism.) 



In human beings, too, in the opinion of Brugsch 31 the 

 findings after administration of benzoic acid apparently do 

 not indicate any other mode of formation of hippuric acid, 

 than by hydrolytic protein cleavage, to be at all convincing. 

 At least the general opinion is distinctly contrary to such a 

 belief. 32 



Hippuric Acid Formation in Herbivora. In herbivora 

 an essentially different situation exists. The mutually 



29 N. Mutch, Journ. of Physiol., U, 176, 1912. 



30 Th. Brugsch and J. Hirsch, Zeitschr. f . exper. Pathol., 3, 663, 1906. 



81 Th. Brugsch and J. Tsuchija, Zeitschr. f. exper. Pathol. 5, 731, 737, 1909. 

 52 J. Lewinski (Minkowski's Clinic, Greifswald), Arch. f. exper. Pathol., 

 58, 397, 1908; Th. Brugsch, Zeitsch. f. exper. Pathol., 5, 731, 1909. 



