xx. Proceedings. [March 16th, 1920. 



that the conversion of tryptophane into kynurenic acid is susceptible 

 •of a simple explanation, and that the process is primarily one of 

 oxidation. The first product might well be the keto-acid (IV) 

 which then suffers further oxidation resulting in the fission of the 

 indole ring and the formation of the compound V. 



C.CH 2 .CO.COOH /\ x/ /CO.CH 2 .CO.COOH 



11 I ! 



CH ^/Nnh.cooh 



IV. V. 



This hypothetical intermediate, if produced in the laboratory, 

 would beyond doubt be found to yield kynurenic acid when treated 

 with weak alkalies. The necessary changes being hydrolysis of 

 the unstable carbamic acid grouping and closure of the quinoline 

 ring by the aid of one of those reactions which are known to 

 proceed with the greatest facililty, indeed, in many cases, 

 spontaneously. The process is illustrated below. 



/ co \ 



V. /\/ CH 2 



— > — > 



NH 2 CO.COOH 



+ CO 



CO OH 



! f X | CH 2 



\/\^C.COOH 



N 



keto form. enol form. 



The foregoing suggestion was made by the author in a letter 

 to Professor George Barger, F.R S., in December 19 19, and in 

 February of this year Dr. Barger has informed me that Ellinger 

 has succeeded in preparing the keto-acid (IV) and finds that when 

 this is given to dogs the kynurenic acid formation is increased. 

 This result strongly supports the view which is expressed above. 



A paper by Professor Arthur Lapworth, D.Sc, F.R.S., 

 entitled " Latent polarities of Atoms and Mechanism of 

 Reaction, with Special Reference to Carbonyl Com- 

 pounds." was, in the author's absence, read by Professor 

 Robert Robinson. 



Professor Robert Robinson, D.Sc, F.R.S., then read a paper 



entitled "The Conjugation of Partial Valencies." 



These two papers are printed in full in the Memoirs. 



