PREFACE 



A new book on evolution, which can lay little 

 claim to novelty of fact or treatment, certainly 

 demands an explanation, if not an apology. My 

 choice of subject for the Westbrook lectures of 1914 

 was determined by the very general misapprehension 

 in the public mind concerning the present status of 

 the evolutionary theory among men of science. It 

 is widely believed that the theory is an outworn 

 device, which naturalists are beginning to discard 

 and that soon it will have a merely historical in- 

 terest. This misunderstanding, for such it is, has 

 arisen from the debates among zoologists and botan- 

 ists as to the manner in which evolution has actually 

 occurred and the efficient causes which have brought 

 it about, and, further, from the ambiguous way in 

 which the term :< Darwinism' is often employed. 

 Frequently, the term is made a synonym of evolu- 

 tion, but it ought properly to be restricted to Dar- 

 win's explanation of evolution by natural selection. 



It seemed that a useful service might be rendered 

 by making an outline review of the evidence upon 

 which the doctrine of evolution is founded, for the 

 nature and scope of this evidence are but little under- 

 stood by the educated, though non-scientific pub- 

 lic. The interest displayed in these topics by the 



