CHEMISTRY OF THE PTOMAINES. 247 



long to the same system ; while ITundeshagen holds that 

 they are distiuct. Instead of the salt presenting an in- 

 stance of trimorphism as first stated by Hundeshagen, it 

 would seem that but two forms occur — anhydrous mono- 

 clinic and octahedra with one molecule of water of crystal- 

 lization. It contains always more or less water of crystal- 

 lization which it does not give up completely over sulphuric 

 acid, but only at 110° (Beieger). The natural platino- 

 cliloride becomes strongly electric on rubbing, whereas the 

 synthetic choline double salt does not become electric. It 

 melts at 225° with effervescence (Jahns). 



The AuROCHLORiDE, CsHj.NO.Cl.AuCij (Au = 44.4.S 

 ])er cent.), is crystalline and is difficultly soluble in cold 

 water, but can be recrystallized from iiot water or from 

 boiling alcohol. It forms prisms, or gold-yellow long 

 needles, which are very easily soluble in hot water and 

 alcohol (Lippmanx). It can be separated from neuridine 

 aurochloride by its solubility in water (Brieger). On 

 heating, the gold salt melts to a brown liquid (Sghulze) 

 and decomposes at 264°. 



The Mercurochloeide, CsHi^NO.Cl.eHgOa, is ex- 

 tremely difficulty soluble even in hot water. On this 

 account the mercury salt is very convenient for the separa- 

 tion of choline from accompanying bases. 



The PiCRATE, C5H,^NO.0CeH2(NO2)3, forms long, broad 

 needles which are more easily soluble thau neuridine picrate, 

 and hence can be separated by recrystallization. It is more 

 easily soluble in alcohol than in water. 



Pliysiological Action of Choline. — Choline was regarded 

 for a long time as physiologically inert, but this belief 

 was set aside by Gaehtgexs (1870), who showed that, 

 when given in large quantity, it possessed a toxic action. 

 This observation of Gaehtgexs has since been con- 

 firmed by Glattsk and Luchsijstgee, Brieger, and 

 BoEHM. The chloride of choline produces in animals the 

 same muscarine-like symptoms of poisoning as are devel- 

 oped by the vinyl base nenrine, the only difference lies in 

 the intensity of the action. In order to bring about a 

 physiological disturbance, choline must be given in rela- 



