6o THE SIMPLER NATURAL BASES 



Koch, failed to isolate Thudichum's non-methylated " ox-ethylamin " 

 from kephalin, and agreed with Koch that one N-methyl group is 

 present. Frankel and Linnert [1910] state that sahidin, from human 

 brain, also contains a base with fewer methyl groups than choline. 

 On the other hand Cousin [1907] could only obtain choline from 

 kephalin. Koch, and Frankel and Neubauer did not isolate their 

 supposed monomethylated base and their results have been criticised 

 by Baumann [1913]; he and Trier [1913, 5] find that amino-ethyl 

 alcohol, when heated with hydriodic acid, gives off some ethyl iodide, 

 thus simulating the presence of an N-methyl group. It should 

 further be remembered that the accuracy of Herzig and Meyer's 

 method for determining N-alkyl groups is not sufficiently great for 

 the certain determination of their number in a molecule of the size of 

 lecithin, and that its application becomes wholly illusory if more than 

 one base is present. 



Further mention of the presence in phosphatides of bases other 

 than choline is to be found in papers by Erlandsen [1907] (on 

 cuorin from ox hearts), by Baskoff [1908] (on the phosphatides of 

 horse liver), by MacLean [1909], by Njegovan [1911], and in Trier's 

 book on plant bases [1912, 3, pp. 96-101]. According to Trier, 

 Njegovan's base "vidine" was merely choline containing a little 

 ammonia as impurity. 



Neurine, Vinyltrimethyl-ammonium Hydroxide, 



/OH 

 (CHa), : Nf 



Neurine was the name applied by Liebreich to a base obtained in 

 the hydrolysis of protagon. Baeyer [1866] found that Liebreich's 

 neurine yielded a mixture of platinichlorides, difficult to separate, 

 but by means of the aurichlorides he subsequently [1869] showed that 

 the principal base was identical with Strecker's choline. For the other 

 base, which Baeyer obtained pure by the elimination of water from 

 choline by chemical means, he reserved the name neurine, and Brieger 

 [1885, I, p. 32] sharply differentiated the two bases; for a time 

 much confusion was introduced by the continued use, by some 

 authors, of neurine as a synonym for choline, but eventually the term 

 neurine was restricted to the unsaturated base. 



According to Gulewitsch [1899, under choline] protagon does not 

 yield neurine at all, but only choline. It is very doubtful whether 

 neurine occurs in the body or body fluids, and apart from the old con- 

 fusion of nomenclature, statements concerning its presence should be 



