M. Frohde on a new Aromatic Acid, 521 



neutralize one another. This is probably the case with many 

 other substances : they are in the same condition as racemic aci(J, 

 which was supposed to be inactive, until Pasteur showed the 

 reverse. 



Among the oxidation products of gelatine and albuminous 

 substances, Schlieper observed the presence of an oily body with 

 an odour like that of cinnamic aldehyde. It occurs along with 

 hydrocyanic acid, acetonitrile, propionitrile, valeronitrile, and 

 hydride of benzoyle. It was also found by Giickelberger among 

 the oxidation products of fibrine, albumen, and caseine. "Frohde 

 has investigated this body*, and has found it to be an aldehyde, 

 which by oxidation is converted into a new aromatic acid. 



He obtained it in greatest quantity by the oxidation of gela- 

 tine by a mixture of sulphuric acid and bichromate of potass ; 

 the distillate from this action was neutralized with carbonate of 

 soda, and the liquid evaporated to dryness : the soda salts were 

 decomposed with sulphuric acid, and the liberated solid acids 

 freed from the accompanying volatile fatty acids by filtration 

 and by crystallization. The solid acids contained the new acid ; 

 it was separated from benzoic acid, which accompanies it, by 

 treatment with hot water, in which it is insoluble, while benzoic 

 acid readily dissolves. The quantity was found to be about 

 y 1 ^ per cent, of the gelatine taken, that of benzoic acid being 

 ■J. per cent. 



The melting-point of the new acid is 97°, and it solidifies at 

 93 — 94°. It is readily soluble in ammonia and in ether. It 

 expels carbonic acid from carbonates ; ignited, it burns with a 

 smoky flame like benzoic acid. It has the formula C 12 H* O 4 , 

 and the author names it collinic acid. Its neutral silver salt has 

 the formula C 12 H 3 AgO 4 ; and there is a basic salt, C 12 H 3 AgO 4 , 

 AgO. The baryta salt has the formula C 12 H 3 BaO 4 + HO. The 

 acid yields with iron a reddish-yellow precipitate. 



The aldehyde of collinic acid is a viscous colourless liquid, 



which by absorption of oxygen assumes a golden-yellow colour. 



When digested with a strong solution of ammonia, it is con- 



(C 12 H 3 ) 3 ~l 

 verted into a crystalline body, which is apparently v J 3 f N 2 , 



corresponding to hydrobenzamide. 



Kolbe has given a preliminary notice f of some interesting re- 

 searches which have been made in his laboratory. 



Vogt investigated the action of reducing agents on the body 

 (C 12 H 6 ) (S 2 4 ) CI, in the expectation of replacing chlorine by 



* Journal fur Praktische Chemie, vol. lxxx. p. 34 1. 

 f Liebig's Annalen, September 1860. 



Phil Mag, 8, 4. No. 136. Bwpph Vol. 20. 2 M 



