﻿viii 
  Preface 
  by 
  the 
  Author 
  

  

  summer 
  of 
  1904, 
  and 
  these 
  lectures 
  are 
  offered 
  in 
  this 
  

   form 
  to 
  a 
  public 
  now 
  thoroughly 
  interested 
  in 
  the 
  pro- 
  

   gress 
  of 
  modern 
  ideas 
  on 
  evolution. 
  Some 
  of 
  my 
  experi- 
  

   ments 
  and 
  pedigree-cultures 
  are 
  described 
  here 
  in 
  a 
  man- 
  

   ner 
  similar 
  to 
  that 
  used 
  in 
  the 
  " 
  Mutationstheorie," 
  but 
  

   partly 
  abridged 
  and 
  partly 
  elaborated, 
  in 
  order 
  to 
  give 
  a 
  

   clear 
  conception 
  of 
  their 
  extent 
  and 
  scope. 
  New 
  experi- 
  

   ments 
  and 
  observations 
  have 
  been 
  added, 
  and 
  a 
  wider 
  

   choice 
  of 
  the 
  material 
  afforded 
  by 
  the 
  more 
  recent 
  cur- 
  

   rent 
  literature 
  has 
  been 
  made 
  in 
  the 
  interest 
  of 
  a 
  clear 
  

   representation 
  of 
  the 
  leading 
  ideas, 
  leaving 
  the 
  exact 
  and 
  

   detailed 
  proofs 
  thereof 
  to 
  the 
  students 
  of 
  the 
  larger 
  book. 
  

  

  Scientific 
  demonstration 
  is 
  often 
  long 
  and 
  encumbered 
  

   with 
  difficult 
  points 
  of 
  minor 
  importance. 
  In 
  these 
  lec- 
  

   tures 
  I 
  have 
  tried 
  to 
  devote 
  attention 
  to 
  the 
  more 
  im- 
  

   portant 
  phases 
  of 
  the 
  subject 
  and 
  have 
  avoided 
  the 
  de- 
  

   tails 
  of 
  lesser 
  interest 
  to 
  the 
  general 
  reader. 
  

  

  Considerable 
  care 
  has 
  been 
  bestowed 
  upon 
  the 
  indica- 
  

   tion 
  of 
  the 
  lacunae 
  in 
  our 
  knowledge 
  of 
  the 
  subject 
  and 
  

   the 
  methods 
  by 
  which 
  they 
  may 
  be 
  filled. 
  Many 
  inter- 
  

   esting 
  observations 
  bearing 
  upon 
  the 
  little 
  known 
  parts 
  

   of 
  the 
  subject 
  may 
  be 
  made 
  with 
  limited 
  facilities, 
  either 
  

   in 
  the 
  garden 
  or 
  upon 
  the 
  wild 
  flora. 
  Accuracy 
  and 
  per- 
  

   severance, 
  and 
  a 
  warm 
  love 
  for 
  Nature's 
  children 
  are 
  

   here 
  the 
  chief 
  requirements 
  in 
  such 
  investigations. 
  

  

  In 
  his 
  admirable 
  treatise 
  on 
  Evolution 
  and 
  Adaptation 
  

   (New 
  York, 
  Macmillan 
  & 
  Co., 
  1903) 
  , 
  Thomas 
  Hunt 
  Mor- 
  

   gan 
  has 
  dealt 
  in 
  a 
  critical 
  manner 
  with 
  many 
  of 
  the 
  

   speculations 
  upon 
  problems 
  subsidiary 
  to 
  the 
  theory 
  of 
  

   descent, 
  in 
  so 
  convincing 
  and 
  complete 
  a 
  manner, 
  that 
  I 
  

   think 
  myself 
  justified 
  in 
  neglecting 
  these 
  questions 
  here. 
  

   His 
  book 
  gives 
  an 
  accurate 
  survey 
  of 
  them 
  all, 
  and 
  is 
  

   easily 
  understood 
  by 
  the 
  general 
  reader. 
  

  

  In 
  concluding 
  I 
  have 
  to 
  offer 
  my 
  thanks 
  to 
  Dr. 
  D. 
  T. 
  

   MacDougal 
  and 
  Miss 
  A. 
  M. 
  Vail 
  of 
  the 
  New 
  York 
  Botan- 
  

   ical 
  Garden 
  for 
  their 
  painstaking 
  work 
  in 
  the 
  prepara- 
  

   tion 
  of 
  the 
  manuscript 
  for 
  the 
  press. 
  Dr. 
  MacDougal, 
  by 
  

  

  