740 URINE. 



Syntheses of aromatic substances with other atomic groups occur 

 frequently. To these syntheses belongs, in the first place, the conjugation 

 of benzoic acid with glycocoll to form hippuric acid, the discovery of which 

 is generally ascribed to WOHLER, but according to HEFFTER l more cor- 

 rectly to KELLER and URE. All the numerous aromatic substances which 

 are converted into benzoic acid in the body are voided partly as hippuric 

 acid. This statement is not true for all species of animals. According to 

 the observations of JAFFE, 2 benzoic acid does not pass into hippuric acid 

 in birds, but into another nitrogenous acid, ornithuric acid, CigH^o^O^ 

 This acid yields as splitting products, besides benzoic acid, ornithine, a body 

 which has been spoken of on page 159. Not only are the oxybenzoic acids 

 and the substituted benzoic acids conjugated with glycocoll, forming corre- 

 sponding hippuric acids, but also the above-mentioned acids, toluic, 

 mesitylenic, cumic, and phenylacetic acids. These acids are voided as 

 toluric, mesitylenuric, cuminuric, and phenaceturic acids. 



It must be remarked in regard to the oxybenzoic acids that a conju- 

 gation with glycocoll has been shown only with salicylic and p-oxybenzoic 

 acid (BERTAGNINI, and others), while BAUMANN and HERTER S find it 

 only very probable for ra-oxybenzoic acid. According to BALDONI 4 

 in dogs the salicylic acid does not pass into salicyluric acid, and he indeed 

 found two acids which he calls ursalicylic acid, Ci 5 Ni 4 O 8 and uramin- 

 salicylic acid, C 16 Hi 6 NO 8 . The oxybenzoic acids are also in part elimi- 

 nated as conjugated sulphuric acids, which is especially true for m-oxy- 

 benzoic acid. The three aminobenzoic acids, according to the experiments 

 of HILDEBRANDT, on rabbits, appeared at least in part unchanged in the 

 urine. SALKOWSKI found, as was later confirmed by R. COHN, S that 

 in rabbits m-aminobenzoic acid passes in part into uraminobenzoic acid, 

 H2N.CO.ftN.C 6 H 4 .COOH. It is also in part eliminated as aminohip- 

 puric acid. 



The behavior of the halogen-substituted compounds of toluene varies 

 in different animals according to HILDEBRANDT'S experiments. In dogs 

 they are converted into the corresponding substituted hippuric acid. In 

 rabbits o-bromtoluene is completely changed to hippuric acid, the m- and 

 2>-bromtoluene only partly. The three chlortoluenes are converted in 

 rabbits into the corresponding benzoic acid and are eliminated as such 

 and not as hippuric acid. 



1 Die Ausscheidung korperfremder Substanzen im Hani, Ergebnisse der Physiol., 

 4, 252. 



2 Ber d. d. chem. Gesellsch., 10 and 11. 



3 Zeitschr. f . physiol. Chem., 1, where Bertagnini's work is also cited. See also 

 Dautzenberg, Maly's Jahresber., 11, 231. 



4 Arch. f. exp. Path. u. Pharm., 1908, Suppl. Bd. (Schmiedeberg's Festschrift). 

 5 Salkowski, Zeitschr. f. pyhsiol. Chem., 7; Cohn, ibid., 17; Hildebrandt, Hof- 



meister's Beitrage, 3. 



