FORMATION OF HIPPURIC ACID. 685- 



followed by a diminution in the second, and that, for example, quinic acid pro- 

 duces a diminution in the excretion of uric acid corresponding to the increased 

 formation of hippuric acid (WEISS, LEWIN), cannot be considered as sufficiently 

 proven (HuPFER 1 ). 



As the thorough investigations of WIECHOWSKI teach, the synthesis 

 of hippuric acid does not stand in any direct relation to the extent of 

 protein metabolism; it varies, on the contrary, with the duration of 

 circulation of benzoic acid and the quantity of glycocoll present in 

 the body. The amount of the latter in intermediary metabolism is so 

 great that in rabbits, on the administration of benzoic acid, more than 

 one-half of the total urine nitrogen may exist as glycocoll. MAGNUS- 

 LEVY 2 found in rabbits and sheep up to 27.8 per cent of the total nitro- 

 gen as hippuric-acid nitrogen, and both investigators have found so much 

 hippuric-acid nitrogen that it could not be accounted for by the glycocoll 

 preformed from the proteins, which amounts to about 4-5 per cent of 

 the total nitrogen of the protein of the food and body. 



In carnivora (dog) and man the conditions are different, accord- 

 ing to BRUGSCH and R. HIRSCH, FEIGEN and BRUGSCH, as here there is 

 no more glycocoll available for hippuric acid formation than is split off 

 from the proteins on hydrolysis. LEWINSKI 3 believes that, nevertheless, 

 in man after abundance of benzoic acid about 34 per cent of the total 

 nitrogen may be excreted as hippuric acid, but BRUGSCH claims that 

 these observations are incorrect. The abundant production of hippuric 

 acid in herbivora induced ABDERHALDEN, GIGON and STRAUSS to 

 investigate the comparative supply of certain ammo-acids in carnivora 

 and herbivora, and they found in cats, rabbits and hens that the percentage 

 quantity of glycocoll split off from the entire organism (with the exception 

 of the intestinal contents and fat and feathers) by hydrolysis was the 

 same, namely 2.33 to 3.34 per cent of the proteins. In order to account 

 for the large quantity of glycocoll which can be eliminated as hippuric 

 acid, we must admit of a formation of glycocoll from complexes rich in 

 carbon, and it is quite possible that the benzoic acid combines with higher 

 amino-acids and that the hippuric acid is then formed from this combina- 

 tion by oxidation. The investigations of MAGNUS-LEVY 4 to prove this 



1 Weiss, Zeitschr. f. physiol. Chem., 25, 27, 38; Lewin, Zeitschr. f. klin. Med., 42; 

 Hupfer, Zeitschr. f. physiol. Chem., 37. See also Wiener, "Die Harnsaure," Ergeb- 

 nisse der Physiol., 1, Abt. 1. 



2 Wiechowski, Hofmeister's Beitrage, 7 (literature); A. Magnus-Levy, Munch, med. 

 Wochenschr., 1905. 



3 Brugsch and Hirsch, Zeitschr. f. exp. Path. u. Therap., 3; Brugsch, Maly's 

 Jahresber., 37, 621, and Bioch. Centralbl., 8, 336; Feigen, Maly's Jahresber., 36, 631; 

 Lewinski, Arch. f. exp. Path. u. Pharm., 58. 



4 Abderhalden, Gigon and Strauss, Zeitschr. f. physiol. Chem., 51; Magnus-Levy, 

 Bioch. Zeitschr., 6. 



