vi PREFACE 



ascertained. While it has been my endeavour to 

 reproduce the papers as nearly as possible in their 

 original form, certain alterations have been made, 

 the chief of which are the following : Paper No. 1 

 has been largely rewritten and extended so as to 

 make it more of the nature of an introduction to 

 the subject. In Paper No. 2 the views formerly 

 accepted with regard to 'Anti-complements' have 

 had to be reconsidered in the light of more recent 

 work ^on the ' Deviation of Complement ' ; the 

 changes, however, concern only the interpretation 

 of results. Paper No. 5, which consists essentially 

 of two portions, has been divided ; one portion will 

 be found at page 62, the other at page 100. Certain 

 new sections entitled ' Addenda ' have been added ; 

 for the views expressed in these I am alone responsible. 

 In view of the constant repetition of the same 

 terms in the text, an index has been considered 

 impracticable ; in its place a full table of contents 

 has been drawn up. 



The greater part of the work has been carried out 

 with the aid of grants from the Carnegie Trustees, 

 and for these I have pleasure in recording my 

 indebtedness. I have also pleasure in thanking 

 Dr. Carl H. Browning for his valuable help both in 

 preparing the work for the press and in the correction 

 of proofs. 



ROBERT MUIR. 



UNIVERSITY OP GLASGOW 

 February, 1909. 



