228 ON THE EXCRETION OF 



Schmidt and Rosenhain,* planned to observe the possible pro* 

 duction of kynurenic acid from various quinoline derivatives f 

 introduced directly into the organism, gave only negative re- 

 sults. The observations of Rosenhain and of Haagen4 in 

 which a decrease of from 30 to 50 per cent of kynurenic acid 

 was obtained after administration of intestinal antiseptics 

 (e. g., salol, thymol, naphthalin), suggested a connection be- 

 tween intestinal putrefaction and kynurenic acid excretion. 

 There is, however, no satisfactory evidence in these experi- 

 ments that kynurenic acid has its origin hi the decomposition 

 going on in the intestine, since no data are given regarding 

 the direct action of the drugs administered upon the food util- 

 ization and body metabolism. Thus it seems quite possible, 

 in view of our experiments, that the diminished kynurenic acid 

 excretion observed after naphthalin administration, for example, 

 is to be attributed to poorer absorption of the proteid fed. It 

 may also be recalled hi this connection how many drugs, e. g., 

 antipyrin, antifebrin, salicylates, alcohol, exert a direct influ- 

 ence upon the production of uric acid ; and accordingly similar 

 specific effects may have been at work hi Haagen's experi- 

 ments. Again Baumann observed an undiminished excre- 

 tion of kynurenic acid in a dog in which several days' starving 

 and repeated doses of calomel had freed the intestine from 

 putrefactive processes as shown by the absence of ethereal 

 sulphates in the urine ; while Haagen failed to find any de- 

 crease in kynurenic acid excretion after administering large 

 doses of iodoform, which exerts a pronounced action upon the 

 putrefactive processes in the intestine. || In this connection 

 we may point out that Nuttall and Thierfelder IT have lately 



* Rosenhain, Beitrage zur Kenntniss der Kynurensaurebildung im Thier- 

 korper. Inaugural-Dissertation, Konigsberg, 1886. (J&S&a laboratory.) Cf. 

 also R. Cohn, Zeitachr. f. physiol. Chemie, 1895, xx, p. 210. 



t E. g., carbostyril, quinaldin, oxymethyl-quinoline, kynurin, antipyrin. 



I Haagen, Ueber den Einfluss der Darmfaulniss auf die Entstehung der 

 Kynurensaure beim Hunde. Inaugural-Dissertation, Konigsberg, 1887. (Jaffe's 

 laboratory.) 



Baumann, Zeitschr. f. physiol. Chemie, 1886, x, p. 131. 



|| Cf. Morax, Zeitschr. f. physiol. Chemie, 1886, x, p. 321. 



1 Nuttall and Thierfelder, Zeitschr. f. physiol. Chemie, 1895, xxi, p. 109; 

 1896, xxii, p. 62. 



