448 MM. Licbreich and Baeyer on Protagon and Neurine, 



In conclusion, he points out that this method is susceptible 

 of application to determining the colouring-matter in other sub- 

 stances — such, for instance, as aniline-red, carmine, &c. 



Liebreich* obtained from an alcoholic extract of brain a new 

 substance which he calls protagon. It can be obtained in micro- 

 scopic crystals, and has the formula G 116 H 241 N 4 PO 22 . Liebreich 

 considers it to be a primary constituent of the brain, and that it 

 is very widely distributed in the organism. When protagon is 

 boiled for some time with baryta-water, it is resolved into glyce- 

 rine-phosphoric acid, several fatty acids, and a new basic sub- 

 stance, neurine, which forms with bichloride of platinum a double 

 salt crystallizing from water in hexagonal plates. 



This substance has been investigated by Baeyer f. The crude 

 hydrochlorate of neurine was precipitated with phosphotungstic 

 acid, the washed precipitate decomposed with baryta-water, and, 

 after removing the baryta and adding hydrochloric acid, the 

 substance was evaporated to a syrup. The best mode of further 

 purification consists in its conversion into the platinum double 

 salt. A special investigation of this double salt has shown it to 

 be probable that crude neurine is a mixture of two bases, whose 

 platinum double salts have respectively the formulae 



NG 5 H 14 ClPtCl 2 

 and 



NG 5 H 12 Cl,PtCl 2 . 



When a strong alcoholic solution of hydrochlorate of neurine 

 was treated with strong hydriodic acid, there was obtained a con- 

 siderable quantity of large colourless prismatic crystals, which 

 were found on analysis to have the formula N G 5 H 13 1 2 . Part of 

 this iodine is present as a substitution-product ; the other is pre- 

 cipitated by an aqueous solution of nitrate of silver in the cold. 

 Freshly precipitated chloride of silver also replaced one atom of 

 iodine by chlorine ; and the solution filtered off from the iodide of 

 silver gave with bichloride of platinum a crystalline compound 

 of the formula N G 5 H 13 1 CI, PtCl 2 . 



The reactions here given agree completely with those of a 

 compound which Hofmann obtained by treating trimethylamine 

 with bromide of ethylene : a simple union of the two bodies takes 

 place, resulting in the formation of a beautiful crystallized com- 

 pound, NG 5 H 13 Br 2 . This corresponds to the compound of 

 neurine which contains two atoms of iodine. When this bro- 

 mine-compound is treated with freshly precipitated oxide of silver, 



* Liebig's Annalen, vol. lxxxiv. p. 29. 

 t Liebig's Annalen, December 1866. 



