﻿PEEFACE 
  BY 
  THE 
  EDITOR 
  

  

  PROFESSOR 
  DE 
  VRIES 
  has 
  rendered 
  an 
  additional 
  service 
  

   to 
  all 
  naturalists 
  by 
  the 
  preparation 
  of 
  the 
  lectures 
  on 
  

   mutation 
  published 
  in 
  the 
  present 
  volume. 
  A 
  perusal 
  of 
  

   the 
  lectures 
  will 
  show 
  that 
  the 
  subject-matter 
  of 
  "Die 
  

   Mutationstheorie 
  ' 
  ; 
  has 
  been 
  presented 
  in 
  a 
  somewhat 
  

   condensed 
  form, 
  and 
  that 
  the 
  time 
  which 
  has 
  elapsed 
  

   since 
  the 
  original 
  was 
  prepared 
  has 
  given 
  opportunity 
  for 
  

   the 
  acquisition 
  of 
  additional 
  facts, 
  and 
  a 
  re-examination 
  

   of 
  some 
  of 
  the 
  more 
  important 
  conclusions 
  with 
  the 
  re- 
  

   sult 
  that 
  a 
  notable 
  gain 
  has 
  been 
  made 
  in 
  the 
  treatment 
  

   of 
  some 
  complicated 
  problems. 
  

  

  It 
  is 
  hoped 
  that 
  the 
  appearance 
  of 
  this 
  English 
  version 
  

   of 
  the 
  theory 
  of 
  mutation 
  will 
  do 
  much 
  to 
  stimulate 
  in- 
  

   vestigation 
  of 
  the 
  various 
  phases 
  of 
  the 
  subject. 
  This 
  

   volume, 
  however, 
  is 
  by 
  no 
  means 
  intended 
  to 
  replace, 
  as 
  a 
  

   work 
  of 
  reference, 
  the 
  larger 
  book 
  with 
  its 
  detailed 
  recital 
  

   of 
  facts 
  and 
  its 
  comprehensive 
  records, 
  but 
  it 
  may 
  prove 
  

   a 
  substitute 
  for 
  the 
  use 
  of 
  the 
  general 
  reader. 
  

  

  The 
  revision 
  of 
  the 
  lectures 
  has 
  been 
  a 
  task 
  attended 
  

   with 
  no 
  little 
  pleasure, 
  especially 
  since 
  it 
  has 
  given 
  the 
  

   editor 
  the 
  opportunity 
  for 
  an 
  advance 
  consideration 
  of 
  

   some 
  of 
  the 
  more 
  recent 
  results, 
  thus 
  materially 
  facilitat- 
  

   ing 
  investigations 
  which 
  have 
  been 
  in 
  progress 
  at 
  the 
  

   New 
  York 
  Botanical 
  Garden 
  for 
  some 
  time. 
  So 
  far 
  as 
  

   the 
  ground 
  has 
  been 
  covered 
  the 
  researches 
  in 
  question 
  

   corroborate 
  the 
  conclusions 
  of 
  de 
  Vries 
  in 
  all 
  important 
  

   particulars. 
  The 
  preparation 
  of 
  the 
  manuscript 
  for 
  the 
  

   printer 
  has 
  consisted 
  chiefly 
  in 
  the 
  adaptation 
  of 
  oral 
  

  

  xi 
  

  

  