CHOLIN. 301 



By the action of dilute nitric acid cholin is converted almost wholly 

 into a base the platinochlorid of which is efflorescent, and forms 

 large, bright crystals grouped in bunches. It corresponds to the 

 formula (C,Hj„Nj03Cl)PtCl, + 2Hp (Schmiedeberg and Harnack). 



Nothnagel isolated the same substance, but on attempting to con- 

 vert the platinum salt into the gold compound, he obtained the 

 aurochlorid of trimethylamin. The nature of this base, which is 

 formed also in small quantity on oxidation with concentrated nitric 

 acid, is uncertain. 



According to Mauthner, cholin resembles the caustic alkalis in its 

 action. Although putrefying blood decomposes it into trimethyl- 

 amin, yet, when present in the proportion of 1.4 per cent., it is said 

 to arrest putrefaction. A 1 to 2 per cent, solution like strong alkali 

 dissolves fibrin or coagulated albumin on boiling. 



Nothnagel has shown, contrary to Arndt, that cholin cannot be 

 distilled unchanged with baryta water. It is decomposed into tri- 

 methylamin. On distillation with water it yields a few drops of an 

 aldehyde body, a little neurin (?), and trimethylamin. On dry dis- 

 tillation of cholin it yields also a little of the aldehyde body, a little 

 neurin (?), and chiefly cholin. The latter probably results from re- 

 combination in the distillate of the trimethylamin, ethylene oxid, 

 and water. In general it may be said that concentrated, but not di- 

 lute, solutions are decomposed by boiling. 



The free base forms a syrupy liquid which eagerly takes up car- 

 bonic acid from the air and is converted into the carbonate which 

 forms elongated six-sided plates. The base is easily soluble in water 

 and in absolute alcohol but is insoluble in chloroform or in ether 

 (Gulewitsch). 



The chlorid, CjHj^NO.Cl, is easily soluble in water and in abso- 

 lute alcohol (separation from neuridin hydrochlorid and from betain). 

 It is insoluble in ether, chloroform and benzol. From alkaline 

 solution traces are dissolved by amyl alcohol. It crystallizes over 

 sulphuric acid to needles which readily deliquesce in the air. Potas- 

 sium mercuric iodid produces in solution of the chlorid a crystalline 

 precipitate. For the behavior to other reagents see Table I (also 

 Gulewitsch). The nitrate possesses the formula : 



(CH3)3.N(NOj).CH,.CH,OH. (Schmidt). 



The bromid, Br.N(CH3)3.C2HpH, forms rather long, colorless 

 rhombic plates when ether is added to an absolute alcohol solution 

 of the salt. It deliquesces very rapidly in the air and is decomposed 

 by sunlight, changing color to violet and brown (Nothnagel). 



The iodid, I.N(CH3)3.C2HpH, can be crystallized in the same 

 way as the bromid. It is less deliquescent and is turned yellow by 

 sunlight (Nothnagel). 



The platinochlorid, (C,Hj,NO.Cl),PtCl, (Pt = 31.64 per cent.). 



