PREFACE. 



IN the following pages I have endeavoured to give an account 

 of those basic substances of animals and plants which are of 

 general biological interest, either because of their wide distri- 

 bution, or on account of their close relationship to the proteins 

 and phosphatides. In contradistinction to the typical vegetable 

 alkaloids, these bases have a simple chemical constitution. 



By a more or less arbitrary delimitation of the subject matter, 

 involving for instance the total exclusion of purine bases, I 

 have aimed at giving, in the space at my disposal, a somewhat 

 detailed account of the chemistry of the bases dealt with, and 

 of their derivatives. Some, like the amines and adrenaline, 

 are remarkable on account of their physiological action, and in 

 each case, therefore, a brief description of this action has been 

 added. In this way I have endeavoured to make the mono- 

 graph also of interest to those who are concerned with the 

 biological rather than with the chemical aspect of the subject. 



A brief chapter on the practical methods used in the 

 isolation of the simple bases has been added, and special 

 attention has been given, to the bibliography which extends 

 to the autumn of 1913. 



It is a pleasant duty to express my great indebtedness to 

 Dr. H. H. Dale, without whose advice and criticism much of 

 the pharmacological sections would have remained unwritten. 



G. B. 



ENOLBFIBLD GREEN, 



SURREY, 

 November, 1913. 



