﻿Preface 
  by 
  the 
  Author 
  ix 
  

  

  his 
  publications, 
  has 
  introduced 
  my 
  results 
  to 
  his 
  Ameri- 
  

   can 
  colleagues, 
  and 
  moreover 
  by 
  his 
  cultures 
  of 
  the 
  muta- 
  

   tive 
  species 
  of 
  the 
  great 
  evening-primrose 
  has 
  con- 
  

   tributed 
  additional 
  proof 
  of 
  the 
  validity 
  of 
  my 
  views, 
  

   which 
  will 
  go 
  far 
  to 
  obviate 
  the 
  difficulties, 
  which 
  are 
  

   still 
  in 
  the 
  way 
  of 
  a 
  more 
  universal 
  acceptation 
  of 
  the 
  

   theory 
  of 
  mutation. 
  My 
  work 
  claims 
  to 
  be 
  in 
  full 
  ac- 
  

   cord 
  with 
  the 
  principles 
  laid 
  down 
  by 
  Darwin, 
  and 
  to 
  give 
  

   a 
  thorough 
  and 
  sharp 
  analysis 
  of 
  some 
  of 
  the 
  ideas 
  of 
  

   variability, 
  inheritance, 
  selection, 
  and 
  mutation, 
  which 
  

   were 
  necessarily 
  vague 
  at 
  his 
  time. 
  It 
  is 
  only 
  just 
  to 
  

   state, 
  that 
  Darwin 
  established 
  so 
  broad 
  a 
  basis 
  for 
  scien- 
  

   tific 
  research 
  upon 
  these 
  subjects, 
  that 
  after 
  half 
  a 
  century 
  

   many 
  problems 
  of 
  major 
  interest 
  remain 
  to 
  be 
  taken 
  up. 
  

   The 
  work 
  now 
  demanding 
  our 
  attention 
  is 
  manifestly 
  that 
  

   of 
  the 
  experimental 
  observation 
  and 
  control 
  of 
  the 
  origin 
  

   of 
  species. 
  The 
  principal 
  object 
  of 
  these 
  lectures 
  is 
  to 
  

   secure 
  a 
  more 
  general 
  appreciation 
  of 
  this 
  kind 
  of 
  work. 
  

  

  HUGO 
  DE 
  VRIES. 
  

   Amsterdam, 
  October, 
  190 
  J^. 
  

  

  