304 CHEMISTRY OF THE PTOMAINS. 



of 100°. The gold salt is anhydrous, dendritic in form, and melts 

 at 154°- 155°. On decomposition with hydrogen sulphid it yields 

 cholin. The platinochlorid crystalliizes in small anhydrous needles 

 which melt at 223°-224°. 



Benzoyl cholin is formed by heating dry cholin chlorid on a water- 

 bath with benzoyl chlorid. It forms a platinum salt crystallizing 

 in fine thread-like needles which melt at 206°. The gold salt 

 forms light-yellow flat needles which are permanent in the air 

 and melt at 183°. The hydrogen in the hydroxyl group of 

 the oxyethyl is, therefore, easily replaced by acid radicals (Noth- 

 nagel). 



Physiological Action of Cholin. — Cholin was regarded for a long 

 time as physiologically inert, but this belief was set aside by Graeht- 

 gens (1870), who showed that, when given in large quantity, it pos- 

 sessed a marked toxic action ; 0.59 gram producing almost instan- 

 taneous death in a cat. This observation of Gaehtgens has since 

 been confirmed by Glause and Luchsinger, Brieger, and Boehm. 

 The chlorid of cholin produces in animals the same muscarin-like 

 symptoms of poisoning as are developed by the vinyl base neurin, the 

 only difierence lies in the intensity of the action. In order to bring 

 about a physiological disturbance, cholin must be given in relatively 

 large doses. Thus Brieger found it necessary to give about 0.1 

 gram of cholin chlorid hypodermically to a one kilogram rabbit in 

 order to bring out the same effects as are obtained by the injection 

 of 0.005 gram of the neurin salt. He also found that the fatal dose 

 for a one kilogram rabbit was about 0.5 gram, which is about ten 

 times as large as the fatal dose of neurin chlorid. Boehm observed 

 that doses of 0.025-0.1 gram produced in frogs general paralysis, 

 which, in a short time, led to death or recovery ; and that in its 

 curara-like paralyzing action cholin resembled artificial muscarin, 

 although the latter is about five hundred times stronger. Atropin, 

 as in the case of neurin and muscarin, antagonizes the action of 

 cholin. Thus, 0.05 gram of the chlorid produced in a frog in one 

 hour diastolic stoppage of the heart. This condition was removed 

 by the injection of 0.001 gram of atropin, the heart-beat rising to 

 the normal in about fourteen minutes ; 0.05 gram of cholin chlorid, 

 given subcutaneously to a rabbit (1,250 grams), produced salivation, 

 which lasted but a short time and did not affect the heart-beat and 

 respiration; 0.10 gram was necessary to bring out all the symptoms ; 

 0.05 gram, given to guinea-pigs, had no effect whatever. Accord- 

 ing to Halliburton (1901) it causes a dilatation of the peripheral 

 blood vessels, especially those of the intestines, and hence a fall of 

 blood pressure. 



Betain (oxyneurin), CjHjjNOj. — This base has been well known 

 for some time, because of its occurrence in the vegetable kingdom. 



