336 Prof. E. N. Horsford on Glycocoll^ 



Constitution of Hippuric Acid. 



It has long been observed that in the preparation of hippuric 

 acid, if the heat be too high or the evaporation too rapid, ben- 

 zoic acid alone is obtained.* 



If it be treated with sulphuric acid and peroxyd of manganese, 

 carbonic acid is evolved, benzoic acid crystallizes from the hot 

 filtered solution, and in the filtrate from the crystals sulphate of 



BerzeliusJ 



t 



acid and a be 



C 4 H 4 NO,. 



Pelouze had attempted to prove that hippuric acid consisted of 

 one atom of hydrocyanic acid ; one of oil of bitter almonds, and 

 one of formic acid : 



Hydrocyanic acid = C H N . . 



Hydrobenzoylic acid = C\ 4 H 8 . . 2 

 Formic acid = c l * H " . . 



3 



Hippuric acid = C I8 H a N 5 



§ entertained the view that it nnnsisted of benzamide 



and fumaric acid. 



Benzamide = q H N 



Fumaric acid = c* YL . 



4 



Hippuric acid = q H N 



2 



a 



Over all this field of speculation Dessaigne's discovery has 

 thrown the most grateful light. 



Hippuric acid contains benzoic acid and glycocoll. With the 

 aid of heat and a strong acid or alkali, the two members may be 



seuarated. 



separated. 



C 13 H 



H 



or C 18 H 9 NO 6 + KO-hHO=C J4 H i O 3 ,KO+C 4 H 4 NO 35 H0. 



By treating glycocoll with caustic potash, we obtain, among 

 other products, cyanid of potassium and ammonia. If a stronger 

 acid be applied to the former it yields hydrocyanic acid, whicn 

 with water falls apart into formic acid and ammonia : 



C 2 NK+3H0+HC1 = KC1+NH 3 +C 3 H0 3 . 



Schwartz, Anna on der Chem. u. Phar, liv, s. 30. Erdmann >, *>»'; ,£. 

 Practische Chemie, xm, s. 422. Dumas, by treating hippuric acid with hyp**' 

 rous acid Annales de Chem. et de Phys., iVn, p. 327. 



f Berzehus Jahresbericht, 1840, s 701 -<*. 



% Jahresbericht, 1836, s. 462. I„ the Bericht for 1831, s. 240, a ^ i!ar J"fV 



n«, a™ \ e « perfect anal r sis of hippuric acid, is to be found. It * a S a,n 

 peated in the Bericht for 1840, s. 704 

 § Leibig's Annalen, Bd. xxvi, s . 60. 



