NEUBm. 291 



On distilling cholin with water, or on dry distillation, a little 

 neurin forms (Nothnagel). Brieger has tried, unsuccessfully, to 

 bring about this dehydration by the putrefaction of pure cholin (I., 

 59). However, Schmidt and Weiss (1887) were more successfiil, 

 and they found that cholin, as well as the hydrochlorid and lactate, 

 is changed by the action of microorganisms into the strongly poison- 

 ous neurin. Their results are given in full under cholin (see page 

 299). More recently (1899) Nesbitt in his study upon auto-intoxi- 

 cations endeavored to show that the toxic neurin may form in the 

 intestines by the dehydration of the cholin in lecithin. After feed- 

 ing dogs on yolk of eggs for several days, the intestines were ligated 

 and eventually the contents were examined. Cholin was found, like- 

 wise good evidence of neurin, and a ptomaiin mentioned on p. 260. 

 From what has been said it is evident that neurin can only arise 

 from cholin, and this, as will be seen later, is derived from lecithin. 

 Cholin may be kept dry or in aqueous solution for four months 

 without change into neurin (Schmidt). 



Neurin is almost invariably accompanied by cholin, from which, 

 however, it can be readily separated by the difference in the solubil- 

 ities of the platinochlorids. It occurs in the mercuric chlorid pre- 

 cipitate (and in the filtrate), and from this it can be obtained, after 

 removal of the mercury, by precipitating the solution of the mixed 

 hydrochlorids in absolute alcohol by platinum chlorid. The platino- 

 chlorids are then separated by recrystallization from water, since the 

 neurin is difficultly soluble, while the cholin salt is readily soluble. 



The free base possesses a strong alkaline reaction, and on contact 

 with the fumes of hydrochloric acid it yields a cloud. It liberates 

 ammonia from its salts even in the cold. It behaves toward the 

 heavy metals like a strong base, and prevents the coagulation of albu- 

 min by heat. On boiling a concentrated solution of neurin it yields 

 trimethylamin. It is not affected by prolonged boiling with baryta 

 or with sodium alcoholate. According to Liebreich, the alkaline 

 solution cannot be neutralized by passing through it carbonic acid. 



With hydriodic acid neurin at 140°— 150° forms trimethylamin 

 ethylene iodid, which, on treatment with silver nitrate, as stated 

 above, forms cholin, or on treatment with silver oxid regenerates 

 neurin (Schmidt). This compound is the same as that prepared by 

 Baeyer. It melts at 231°. 



Fuming hydrobromic acid has no action on- neurin at ordinary 

 temperature or at 100°, but at 160°— 165° it yields trimethylamin- 

 ethylene bromid, which behaves with silver nitrate or oxid as above 

 (Bode and Schmidt). Thus : 



(1) Br.N{CHj),.C,H4Br + 2AgN0, + H^O = NO,.N(CH,),.C,H,OH + 2AgBr + 



HNO3. 



(2) BrN(CH,)s.C,H4Br + Ag,0 = OH.N(CH,),.CH.CH, + 2AgBr. 



