M, 1 



VI PREFACE 



Like other reviews, this cannot be other than a process of 

 stocktaking. I have attempted to submit the main points in 

 evidence up to date ; yet however desirable an absolutely fixed 

 standpoint may appear, it should not be forgotten that opinion 

 must be adjustable to the requirements of every new fact, pro- 

 vided the latter be correctly observed and accurately recorded. 



It is a pleasant duty to express my gratitude to those who 

 have aided me; to my father, and to Professor Alexander Macalister, 

 for ever-ready help and encouragement ; to Professor Elliot Smith 

 and to Dr Marett Tims, who kindly read parts of certain Chapters 

 (viz. xv and vi), upon the subject-matter of which they are 

 recognised as authorities of the highest competence. 



The following have allowed the use of tables or information 

 already published elsewhere : 



Dr Ballantyne and Professor Cunningham of Edinburgh ; 

 Professor Eisler of Halle and Professor Le Double of Tours; 

 Professors Parker and Haswell and Messrs Macmillan and Co. 



I have endeavoured to render full acknowledgment, and hope 

 that no omission has been made. References to literature are 

 provided in the text : a special index contains the names of 

 authors quoted. Where possible, I have attempted to verify 

 or check statements by personal observation. 



