1882.] Leucine and Glycocine into Urea. 185 



Similarly 



2C > H '° PoH + C ' H " °' " 2 {°« H ' {COOH + C0 P'H,, 

 leucine glucose lactic acid urethane 



2C = H «& + c « H « -= 2 { +00 &j 



alanine urethane 



The questions at once arise, Why should not the amido-acid itself 

 be transformed into the carbamate, and why should the glucose be 

 introduced ? Glycocine heated with baryta is converted into 

 carbon dioxide and methylamine ; heated with benzoic acid in a 

 sealed tube, hippuric acid is formed, water being eliminated — 



CH 2 (NH 2 )OOOH + C^H,. COOH = C 9 H 9 N0 3 + H 2 

 glycocine benzoic acid hippuric 



acid 



Consequently when heated it is transformed in some way. We 

 find glucose present in the duodenum and glycogen existing in the 

 liver, the amount being dependent upon the amount of starch and 

 sugar introduced into the alimentary canal, and these substances 

 must have some function to perform. Moreover it appears that 

 when leucine is heated with soda-lime it will not yield all its 

 nitrogen as ammonia unless previously mixed with sugar*. Then 

 again if we turn to the vegetable kingdom, the experiments of 

 Js T ageli"f" show that albumen can be formed by fungi whose nutri- 

 triment consists exclusively of sugar mixed with ammonia. These 

 considerations would apparently furnish some clue to the changes 

 which take place in glucose previous to its transformation into 

 lactic acid or into alcohol; but this point, however, may well be 

 reserved until experiments in the laboratory shall have corroborated 

 or falsified the hypothesis which I have here submitted for considera- 

 tion. My friend Mr A. Scott has already made some experiments 

 for me in the University laboratory, but too few in number to 

 afford as yet any definite result. 1 have to tender my thanks to 

 him, as well as to Mr Pattison Muir and Mr Sheridan Lea, for very 

 valuable suggestions I have obtained in discussions I have been 

 permitted to have with them on the subject matter of this 

 paper. 



* Watts, Dictionary. 2nd Suppl. p. 734. 

 t Siteungsb. d. Bayr. Acad. d. Wiss, 187'.). 



VOL. IV. PT. [V. 14 



