AMIDINES AND AMINES 27 



is that every one of them contains the amidine 

 grouping in their molecules. Guanidine is one 

 of the simplest amidines. Up to the present, 

 therefore, every substance yet tried which contains 

 the amidine grouping will cause the cell-division 

 of human lymphocytes. 



Those substances which were not effective 

 before were then retried in the presence of 

 atropine. Still, they were all ineffective with 

 the exception of one ethylamine. 



Now ethylamine, like the aniline dyes, does 

 not contain the amidine grouping in its molecule ; 

 and the fact that it is an auxetic if augmented 

 by atropine led us to try other amines both with 

 and without atropine. If atropine is present, the 

 following primary aliphatic amines are auxetics : 



Natural : methylamine . . (0'3 c.c., 1 per cent) 



Artificial : ethylamine . . . (0'2 c.c. ) 



propylamine . . (0'5 c.c. ,, ) 



isobutylamine . ( ) 



but they are inert by themselves. 



The secondary amines, dimethylamine, diethy- 

 lamine, and diphenylamine (all artificial), were 

 tested with and without atropine, but they have 

 no action. 



The following amino-acids all proved to be 

 auxetics, provided their action is augmented by 

 atropine : 



Natural : glycocoll . . . (1 c.c., 1 per cent) 

 leucine ....( ) 



tyrosine. . ( ) 



Artificial : asparagin . . . ( ) 



