32 



Scientific Proceedings (87). 



rigorous proof of the accepted theory requires an elementary 

 composition of C = 65.70, H = 10.79, N = I -74. P = 3- 86 - It 

 further requires the nitrogen of the molecule to be composed 

 entirely of choline. Hence lecithin should not contain even a 

 part of its nitrogen in the form of free amino groups. 



The work up to the present has satisfied many of the require- 

 ments. The fatty acids and the glycerophosphoric acid have been 

 identified; and MacLean has prepared, at least once, a sample of 

 lecithin that was free of amino-nitrogen. However, this one 

 sample was very incompletely analyzed. All other samples of 

 lecithin prepared by various workers contained amino-nitrogen in 

 their molecule, and from the standpoint of elementary analysis 

 showed a marked disagreement with the theory. This is well 

 illustrated by the following table: 



Author. 



Source. 



C. 



H. 



N. 



P. 



Choline, 

 Per Cent. 





Brain 

 Liver 



Egg 



Heart 



Not given 

 From CdCh salt 



66.75 

 64.64 



18.67 

 10.71 



1.81 

 i-95 



4.00 

 4.00 





Baskoff 





Heffter 



25 



66 

 42 

 41.4 



Stern and Thierfelder . . 

 MacLean 



Eppler 



64.63 

 64.18 

 66.29 

 66.27 

 66.46 



10.96 

 10.60 

 IO.17 

 IO.32 

 10.69 



1.79 

 1.87 

 1.87 

 1.85 

 1.87 

 1.89 

 1.85 

 1.87 



3-95 

 3-95 

 3-95 



3- 97 



4- 03 

 4.04 

 4.00 

 4-15 



MacLean 



68 

 66 

 98.7 





















The analytical data obtained by Ritter on hydrolecithin showed 

 better agreement with the theory, and one might have been in- 

 clined to regard the material of Ritter as such that contained all 

 the necessary and sufficient proof in favor of the conventional 

 theory. Unfortunately, Ritter did not determine the amino- 

 nitrogen of the reduced lecithin, and hence failed to furnish 

 definite proof of its purity. 



Indeed, the present report contains data unmistakably proving 

 that hydrolecithin of an elementary composition fully harmonizing 

 with the theory may be and generally is impure, containing 

 between 10 and 20 per cent, of its nitrogen in the form of amino- 

 nitrogen. 



This finding has a great significance because of its bearing on 

 the structure of cephalin, and the work is presented in its present 



