APPKNDIX TO CHAPTER IV CHOLINK 155 



mercuric chloride in alcoholic solution, the precipitate was extracted 

 with boiling water, in which the mercury compounds of peptones and 

 proteins were completely insoluble. The choline mercurichloride 

 crystallised out almost completely from the filtrate on cooling, and the 

 mercury salts of other putrefaction bases remained in solution. 



Double salts of choline chloride with cadmium and with zinc 

 chloride are precipitated in alcoholic solution. 



StanSk [1905] has described two periodides. With excess of 

 iodine in potassium iodide an ennea-iodide C 5 H 14 ONI . I 8 is formed as 

 a brown precipitate, changing to shiny green crystals; in a O'l-i per 

 cent, choline solution only 2-3 per cent, of the total escapes precipita- 

 tion. When choline is in excess a hexa-iodide C 5 H U ONI . I 5 results. 



Amino-ethyl Alcohol. 



The free base distils at 160-165 and 718 mm. The hydrochloride 

 C 2 H 5 ON . HC1 is hygroscopic. The aurichloride C 2 H 5 ON . HAuCl 4 

 crystallises slowly from concentrated hydrochloric acid containing 

 excess of gold chloride in large crystals, melting at 186-187. The 

 platinichloride is anhydrous. 



Amino-ethyl alcohol differs from choline in not being precipitated by 

 potassium bismuth iodide, and not by phosphotungstic acid except in 

 concentrated solutions. Heated with hydriodic acid, as in Herzig and 

 Meyer's method for the determination of N-methyl groups, it gives 

 off a little ethyl iodide [Trier, 1913, 5]. 



Neurine. 



The separation of neurine from dwline may be carried out by 

 fractional crystallisation of- the platinum salts ; the large crystals of 

 choline platinichloride are readily obtained pure, but the small, less 

 soluble crystals of the neurine salt are only purified with difficulty 

 (Gulewitsch [1899 ; under choline]). 



The chemical properties of neurine and some of its compounds 

 have been described in detail by Gulewitsch [1898, 2]. It is a strong 

 base and, like choline, it liberates ammonia from its salts and prevents 

 the coagulation of protein. It may be boiled in dilute solution with- 

 out decomposition, and is not changed by boiling with concentrated 

 baryta. Its behaviour with alkaloidal reagents is very similar to that 

 of choline ; generally the reactions are more delicate ; thus with 

 phosphotungstic acid and with potassium tri-iodide a micro-crystalline 

 precipitate is produced which is even indicated at a dilution of I : 

 200,000. 



