SYNTHESES OF AROMATIC SUBSTANCES. 783 



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

 are converted into ben zoic 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/ benzoic acid does not pass into hippuric 

 acid in birds, but after conjugation with ornithin, into the correspond- 

 ing acid, ornithuric acid, (a-S-dibenzoyldiamino valeric acid). Not only 

 are the oxybenzoic acids and the substituted benzoic acids conjugated with 

 glycocoll, forming corresponding 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 conjugation with 

 glycocoll has been shown only with salicylic and p-pxybenzoic acid (BERTAGNINI, 

 and others), while BAUMANN and HERTER 2 find it only very probable for m- 

 oxybenzoic acid. According to BALDONi, 3 in dogs, the salicylic acid does not pass 

 into salicyluric acid, and he indeed found two acids which he calls ursalicylic 

 acid, CisHuOg and uramin-salicylic acid, CieHieNOg. The oxybenzoic acids are 

 also in part eliminated as conjugated sulphuric acids, which is especially true for 

 m-oxybenzoic 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, 4 that in rabbits m-amino- 

 benzoic acid passes in part into uraminobenzoic acid, H 2 N.CO.HN.C 6 H4.COOH. 

 It is also in part eliminated as aminohippuric 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-brom- 

 toluene is completely changed to hippuric acid, the ra- and p-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. 



The substituted aldehydes are of special interest as substances which 

 may undergo conjugation with glycocoll. According to the investiga- 

 tions of R. CoHN 5 on this subject, o-nitrobenzaldehyde when introduced 

 into a rabbit is only in a very small part converted into nitrobenzoic 

 acid, and the chief mass, about 90 per cent, is destroyed in the body. 

 According to SIEBER and SMiRNOW 6 m-nitrobenzaldehyde passes in dogs 

 into m-nitrohippuric acid, and according to COHN into urea-m-nitro- 

 hippurate, but in rabbits a different action results. In this case not only 

 does an oxidation of the aldehyde into benzoic acid take place, but the 



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



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

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



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

 4 Salkowski, Zeitschr. f. physiol. Chem., 7; Cohn, ibid., 17; Hildebrandt, Hof- 



meister's Beitrage, 3. 



6 Zeitschr. f. physiol. Chem., 17. 

 6 Monatshefte f. Chem., 8. 



