254 ON THE EXCRETION OF 



experiments regarding the formation of kynurenic acid in the 

 dog from body proteids during inanition, several rabbits were 

 starved for varying periods (three to five days) and the urine 

 then examined. No kynurenic acid was found. Lastly the 

 urine of man has been examined in wasting diseases (severe 

 diabetes) without avail. Since Hauser * and Solomin f have 

 observed that kynurenic acid introduced into the organism 

 of man, rabbit, or dog, is in good part destroyed (especially in 

 the case of the first two), it may be, as Solomin suggests, that 

 kynurenic acid is absent from human and rabbit's urine not 

 because it fails to be produced, but rather because it is de- 

 stroyed in these organisms as rapidly as it is formed. 



Theoretical considerations regarding the quantity of kynurenic 

 acid obtainable. That the absolute amount of kynurenic acid 

 produced at any time should be large is scarcely to be ex- 

 pected. If, as the experiments of Lusk and his co-workers 

 have indicated, the proteid molecule yields on cleavage in the 

 body an amount of sugar equal to nearly 60 per cent, there 

 remains "a nitrogen-containing radical in which the carbon 

 and nitrogen would appear in the atomic ratio of 2.2 of C to 1 

 of N."J Now kynurenic acid, C 10 H T NO 8 , contains 10 of C to 

 1 of N ; obviously the nitrogenous proteid radicals could not 

 yield large quantities of a body of the composition indicated. 



Summary. Kynurenic acid is a direct product of proteid 

 katabolism, and, as Baumann's experiments indicated, does 

 not owe its immediate origin to putrefactive changes in the 

 intestine. 



Kynurenic acid excretion accompanies accelerated proteid 

 decomposition, whether this condition be brought about by 

 starvation, ingestion of large amounts of proteid food, or 

 through the action of drugs (borax, phlorhizin). 



Similar results follow the ingestion of both animal and 

 vegetable proteids, as well as proteoses; gelatin, however, 



* Hauser, Arch, f . exper. Pathol. u. Pharmakol., 1895, xxxvi, p. 1. 



t Solomin, Zeitschr. f. physiol. Chemie, 1897, xxiii, p. 497. 



| Keilly, Nolan, and Lusk, Amer. Jour. Physiol., 1898, i, p. 409. 



