1903.] Action of Choline, Neurine, Musearine, and Beta/inc. 321 



As regards choline, neurine, and the cerebro-spinal residue our 

 report of a summary examination of these three bodies was to the 

 effect that choline as compared with neurine was inert, that cerebro- 

 spinal residue was inert while fresh, but became active when oxidised, 

 and that " as regards an action upon isolated nerve the order of 

 efficacy of the samples in our possession was (1) neurine, (2) muscarine, 

 (3) choline."* 



This result, although accurate for the particular samples in our 

 hands, was, however, vitiated by an error in their description. 

 The so-called " neurine hydrochloride " of our first experiments 



FIG. 1 (Musearine nitrate). 



Before, 



3313 to 3317, was in reality the base neurine, which in 25-per cent, 

 solution has a basic reaction requiring for its neutralisation 2 vols. of 

 normal acid. The effects of 4, 2, 1, and | and J per cent, solutions 

 of neurine are, therefore, partly or wholly basic effects by 0*32, 0-16, 

 0-08, 0'04, and 0'02 solutions of normal alkali. These effects were in 

 fact such as we are accustomed to expect from other basic solutions such 

 as potash or soda, of strength ranging from 0'20 to 0'05 normal (acid 

 and alkali). 



A strict comparison between the two bodies requires the use of 

 both bodies as bases, neither of which conditions we have yet found 

 means to fulfil. For, on the one hand, neurine when neutralised by an 

 acid (e.g., hydrochloric), is decomposed to an ammonium salt, etc., 

 on the other, choline as base is extremely unstable. 



A fresh series of experiments for determining the relative 

 effects of choline and neurine upon isolated nerve was made in the 

 summer of 1900. We obtained from Messrs. Merck the four 



* Sowton and Waller, Internat. Physiol. Congress, Cambridge, 1898, ' Journ. of 

 Physiol.,' vol. 23, suppl., p. 35. 



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