112 UREA. HIPPURIC ACID. AMINOACIDS 



rabbit is able to form glycoeoll synthetically from ammonia 

 and acetic acid ; and as a matter of fact a very appreciable 

 increase in hippuric acid elimination was observed in several 

 experiments in which ammonium acetate and benzoic acid 

 were simultaneously administered. Although, it is true, 

 these studies are not definitely conclusive, E. Friedmann 42 

 has recently declared the possibility of a synthetic formation 

 of glycocoll from acetic acid and ammonia, with the very 



/COH \ 



actively combining glyoxylic acid (I 1 as a possible 



\COOH / 



intermediate product. A simple synthesis of acetic acid 



a" HI \ 

 ) but 

 ONH 2 / 



/ H \ 



never in glycocoll / ( f H2<NHa> \ . Here may be a .special ( (JJQ ) 



\COOH / \ I / 



X COOH 



instance of the previously discussed (v. supra., p. 69) 

 synthesis of aminoacids from a-ketonic acids and ammonia 

 following the schema: 



R R 



CO + NH, ^ CH.NH 2 +0 



COOH COOH. 



Glycocoll and Ornithin as Detoxifying Agents. We 

 have come to regard this synthetic union of glycocoll 

 and benzoic acid as peculiarly important in that it may 

 be looked upon as eliminating the toxic benzoic acid. 

 It is well known that quite a number of other aromatic acids 

 analogous to benzoic acid may combine with glycocoll in the 

 economy. One of these, phenylpropionic acid (C 6 H 5 . CH 2 . 

 CH 2 . COOH.), Dakin has shown to be very toxic to cats, 43 

 being transformed in the animal partly into acetophenone 

 (C 6 H 5 .CO.CH 3 ) ; although its synthetic compound with 

 glycocoll, phenylpropionylglycocoll ( C 6 H 5 .CH 2 .CH 2 .CO-NH. 



42 E. Friedmann and H. Tachau, 1. c., p. 90. 



43 H. D. Dakin (C. A. Herter's Lab., New York), Jour, of Biol. Chem., 5, 

 413, 1908. 



