CASUAL URINARY CONSTITUENTS. 741 



The substituted aldehydes are of special interest as substances which 

 may undergo conjugation with gl) cocoll. According to the investigations 

 of R. COHN 1 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 2 m-nitrobenzaldehyde passes in dogs into m-nitro- 

 hippuric acid, and according to COHN into urea-ra-nitrohippurate, 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 nitro- 

 group is also reduced to an amino-group, and finally acetic acid attaches 

 itself to this with the expulsion of water, so that the final product is 

 m-acetylaminobenzoic acid, CHs.CO.NH.CeH^COOH. This process is 

 analogous to the action of furfurol, and the reduction does not take 

 place in the intestine, but in the tissues. The p-nitrobenzaldehyde acts 

 in rabbits in part like the m-aldehyde and passes in part into p-acetyl- 

 aminobenzoic acid. Another part is converted into p-nitrobenzoic acid, 

 and the urine contains a chemical combination of equal parts of these 

 two acids. According to SIEBER and SMIRNOW p-nitrobenzaldehyde 

 yields only urea p-nitrohippurate in dogs. The above-mentioned pyridine- 

 carboxylic acid, formed from methylpyridine (a-picoline) passes into the 

 urine after conjugation with glycocoll as a-pyridinuric acid. 3 



To those substances which undergo a conjugation with glycocoll 

 belongs also furfurol (the aldehyde of pyromucic acid), which, when intro- 

 duced into rabbits and dogs, as shown by JAFFE and CoHN, 4 is first oxidized 

 into pyromucic acid and then, after conjugation with glycocoll, elimin- 

 ated as pyromucuric acid, C 7 H 7 NO 4 . In birds this behavior is different, 

 namely, the acid is conjugated with another substance, ornithine, 

 C. 5 Hi2N2O2, which is a diaminovaleric acid, forming pyromucinornithuric 

 acid. 



Furfurol in mammals also undergoes conjugation with glycocoll in 

 other forms. Thus JAFFE and COHN found that it is in part combined with 

 acetic acid, forming furfuracrylic acid, C4H 3 O.CH:CH.COOH, which passes 

 into the urine coupled w r ith glycocoll as furfuracryluric acid. 



It has not been proven how thiophene, C 4 H 4 S, behaves in the animal 

 body. Of methylthiophene (thiotolene), C4H 3 S.CH 3 , a very small part is 

 oxidized to thiophenic acid, C4H 3 S.COOH (LEVY). This acid, as shown 



1 Zeitschr. f. physiol. Chem., 17. 



2 Monatshefte, f. Chem., 8. 



3 In regard to the extensive literature on glycocoll conjugations we refer the reader 

 to O. Kiihling, Ueber Stoffwechselprodukte aromatischer Korper. Inaug.-Diss., 

 Berlin, 1887. 



4 Ber. d. d. Chem. Gesellsch., 20 and 21. 



