viii PREFACE 



The occasions on which the addresses here 

 printed were deHvered are described in an 

 introductory note at the beginning of each 

 Section, Three out of the seven Sections of 

 this volume, viz. I, IV, and V, have already- 

 appeared; four are now published for the first 

 time. 



I have especial reasons for being grateful to my 

 American friends for permission to reprint the 

 address contained in the first Section. The Publi- 

 cation Committee of the American Association 

 for the Advancement of Science did me the 

 honour of choosing the title of my address as 

 the title of the complete work — Fifty Years of 

 Darwinism^ — containing the eleven centennial 

 addresses, in honour of Charles Darwin, delivered 

 on Jan. 1, 1909. The publishers who owned the 

 copyright were very doubtful about the success of 

 the work— unnecessarily as it happened, for I 

 undej'stand that a second edition is already being 

 prepared. In spite of considerations which 

 seemed at the time to be weighty, both Com- 

 mittee and Publishers at once granted me the 

 most free and cordial permission to reprint the 

 address in the present work. 



The Syndics of the Cambridge University Press 

 generously allowed the publication, on Nov. 24, of 

 Section V, which had appeared as Essay XV of 

 Darwin and Modern Science only eight months 



