1240 NEURINE PROTAGON. 



extremely poisonous alkaloid muscarine C 5 H 15 NO 3 . Choline 

 is itself possessed of poisonous properties, and arising as it 

 does from the decomposition of lecithin and protagon is now 

 recognized as one of the alkaloidal products or ptomaines (see 

 below) which occur in putrefying animal tissues. 



Neurine. C 5 H 13 NO. (CH 3 ) 3 =N =CH trimethyl- 



vinyl-ammonium hydroxide. 



This substance is closely related to choline both in composi- 

 tion and origin, but is much more powerfully toxic than that 

 body. It was first described as a product of the decomposition 

 of protagon by caustic baryta, and until recently the names 

 choline and neurine were applied interchangeably to the basic 

 product of the action of baryta on lecithin or protagon first 

 described under the name choline. Later researches have how- 

 ever shewn that neurine differs distinctly both in composition 

 and properties from the older choline, and have further identi- 

 fied it as one of the most commonly occurring and actively 

 toxic of the alkaloidal basic products of the putrefactive decom- 

 position of animal tissues known under the name of the pto- 

 maines. Like choline it is in the pure state a sirupy fluid, 

 with strongly alkaline reaction and is extremely soluble in 

 water. It forms with hydrochloric acid and platinum chloride 

 characteristic double salts which crystallize readily. The 

 double salt which neurine forms with gold chloride crystallizes 

 in yellow needles; it is but slightly soluble in cold water, 

 though soluble in hot water. 



Protagon. C^Hg^PO^ (?). 



A crystalline substance, containing nitrogen and phos- 

 phorus, obtained originally and chiefly from the brain. Prota- 

 gon separates 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 in 

 ether. It is insoluble in water, but swells up and forms a 

 gelatinous mass. It melts at 200 and forms a brown sirupy 

 fluid. 



Preparation. Finely divided brain substance, freed from blood- 

 vessels and connective tissue, is digested at 45 C. with alcohol 

 (85 p.c.) as long as the alcohol extracts anything from it. The 

 united extracts are filtered while hot and the protagon separates out 

 from the filtrate on cooling to 0. It is next thoroughly extracted 

 with ether to get rid of all cholesterin and other bodies soluble in 

 ether, and finally purified by repeated crystallization from warm 

 alcohol. 



By treatment with boiling solution of caustic baryta prota- 



