APR] CHEMICAL BASIS OF THE ANIMAL BODY. 745 



constituent The researches of Hoppe-Seyler and Diakonow tended to 

 shew that protagon was merely a mixture of lecithin and cerebrin. A 

 repetition of Liebreich's experiments has however led Gamgee and Blan- 

 kenhorn 1 to confirm the truth of his results. Protagon appears to separate 

 out from warm alcohol on gradual cooling in the form of very small 

 needles, often arranged in groups : it is slightly soluble in cold, more 

 soluble in hot alcohol, and aether. It is insoluble in water, but swells 

 up and forms a gelatinous mass. It melts at 200 C. and forms a 

 brown sirupy fluid. 



Preparation. Finely divided brain substance, freed from blood and 

 connective tissue, is digested at 45 C. with alcohol (85 p. c.) as long as 

 the alcohol extracts anything from it. The protagon which separates 

 out from the nitrate is well washed with aether to get rid of all 

 cholesterin and other bodies soluble in aether, and finally purified by 

 repeated crystallisation from warm alcohol. 



N eurin (Cholin). C 8 H 15 ISTOa. 



Discovered by Strecker 8 in pig's-gall, then in ox-gall. It does not 

 occur in the free state except us a product of the decomposition of lecithin. 

 It is a colourless fluid, of oily consistence, possesses a strong alkaline re- 

 action, and forms with acids very deliquescent salts. The salts with 

 hydrochloric acid and the chlorides of platinum and gold are the most 

 important. 



Neurin is a most unstable body, mere heating of its aqueous solution 

 sufficing to split it up into glycol, trimethylamin and ethylene oxide. 



Preparation. From yolk of egg. For this see Diakonow *. 



Wurtz 4 has obtained it synthetically, first by the action of glycol hydrochloride 

 on trimethylamin, and then by that of ethylene oxide and water on the same 

 substance. The above, together with the mode of its decomposition, point to the 

 idea that neurin may be regarded as trimethyl-oxyethyl-ammonium hydrate, 

 N(CH 3 ^ 3 (C 2 H 5 0)OH. 



Cerebrin. C 17 H^ N0 3 (?) 



Is found in the axis cylinder of nerves, in pus corpuscles, and 

 largely in the brain. In former times many names were given to the 

 substance when in an impure state ex.gr. cerebric acid, cerebrote, &c. 

 W. Miiller 5 first prepared it in the pure form, and constructed the 

 above formula from his analysis; the mean of these is O, 15 '85. H, 

 11 '2. N, 4*5. C, 6845. Great doubts are however thrown upon 



1 Zeitschr. f. physiol. Chem. Bd. ra. (1879) S. 260, and Jl. of Physiol. Vol. n. 

 (1879) p. 113. 



2 Ann. d. Chem. u. Pharm. Bd. 123, S. 353, Bd. 148, S. 76. 



3 Op. cit. (sub. Lecithin). 



* Ann. d. Chem. u. Pharm. Sup. Bd. 6, S. 116 u. 127. 

 c Ann. d. Chem. . Phat-m. Bd. 105, S. 361. 



