March 16th, 1920.] Proceedings. xix. 



Mr. J. Wilfrid Jackson, F.G.S., and Dr. R. S. Willows, 

 M.A., were nominated Auditors of the Society's Accounts for 

 the session 1919 — 1920. 



Professor Robert Robinson, D.Sc, F.R.S., read a " Note 

 on the Mechanism of the Production of Kynurenic Acid 

 in the Dog." 



Kynurenic acid was discovered in the urine of dogs by J. von 

 Liebig in 1853 (Ann., 86, 125), and was identified by R. Camps 

 (Ber., 1901, 34, 2707) with a synthetically prepared 4-hydroxy- 

 quinoline — 3-carboxylic acid (I) melting at 266 — 267 °C. A. 

 Ellinger (Ber., 1904, 37, 1 801) discovered that the administration 

 of tryptophane (II) to dogs and rabbits resulted in an increased 

 production of the acid and was led to postulate a relation between 

 the two substances, which his further work soon proved to be 

 erroneous. A. Homer (J. Biol. Chem., 1914, 17, 509 — 518) 

 definitely proved that kynurenic acid melts at 288 — 289 , and 

 identified the acid with 4-hydroxyquinoline-2-carboxylic acid (III), 

 which substance, curiously enough, had also been prepared by 

 Camps (Ber., 1901, 34, 2712) by the action of aqueous alcoholic 

 sodium hydroxide on the product of condensation of o-aminoace- 

 tophenone and ethyl oxalate at 150 — i6o°C. 



CH 2 .CHNH 2 .COOH 



— COOH 

 III. 



Homer (J. Biol. Chem., 1915, 22, 391 — 405) considered that 

 the relation between tryptophane and kynurenic acid might not be 

 direct in the sense that the latter substance is actually derived 

 from the former, but that the metabolic processes induced by the 

 tryptophane might involve the synthesis of kynurenic acid in side 

 reactions. This conclusion was reached partly as the result of an 

 experimental study in which it was shown that the ratio between 

 the tryptophane ingested and kynurenic acid excreted was not a 

 simple one, but depended on the age and condition of the animal 

 and partly because the transformation would involve the enlarge- 

 ment of a five-membered ring. It appears to the present author 



