﻿False 
  Atavism 
  187 
  

  

  sort 
  to 
  another, 
  and 
  separation 
  by 
  great 
  dis- 
  

   tances 
  would 
  be 
  required 
  to 
  avoid 
  this 
  source 
  of 
  

   impurity. 
  Unfortunately 
  the 
  arrangements 
  

   and 
  necessities 
  of 
  large 
  cultures 
  make 
  it 
  impos- 
  

   sible 
  to 
  isolate 
  the 
  allied 
  varieties 
  from 
  each 
  

   other. 
  

  

  From 
  a 
  theoretical 
  point 
  of 
  view 
  the 
  origin 
  

   of 
  these 
  impurities 
  is 
  a 
  highly 
  important 
  ques- 
  

   tion. 
  If 
  the 
  breeders 
  ' 
  atavism 
  is 
  due 
  to 
  crosses, 
  

   and 
  only 
  to 
  this 
  cause, 
  it 
  has 
  no 
  bearing 
  at 
  all 
  

   on 
  the 
  question 
  of 
  the 
  constancy 
  of 
  varieties. 
  

   And 
  the 
  general 
  belief, 
  that 
  varieties 
  are 
  dis- 
  

   tinguished 
  from 
  true 
  species 
  by 
  their 
  repeated 
  

   reversion 
  and 
  that 
  even 
  such 
  reversibility 
  is 
  the 
  

   real 
  distinction 
  of 
  a 
  variety, 
  would 
  not 
  hold. 
  

  

  For 
  this 
  reason 
  I 
  have 
  taken 
  much 
  trouble 
  

   in 
  ascertaining 
  the 
  circumstances 
  which 
  attend 
  

   this 
  form 
  of 
  atavism. 
  I 
  have 
  visited 
  a 
  number 
  

   of 
  the 
  leading 
  nurseries 
  of 
  Europe, 
  tested 
  their 
  

   products 
  in 
  various 
  ways, 
  and 
  made 
  some 
  ex- 
  

   periments 
  on 
  the 
  unavoidable 
  conditions 
  of 
  

   hybridizing 
  and 
  on 
  their 
  effect 
  on 
  the 
  ensuing 
  

   generations. 
  These 
  investigations 
  have 
  led 
  me 
  

   to 
  the 
  conclusion, 
  that 
  atavism, 
  as 
  it 
  is 
  gener- 
  

   ally 
  described, 
  always 
  or 
  nearly 
  always 
  is 
  due 
  

   to 
  hybridization, 
  and 
  therefore 
  it 
  is 
  to 
  be 
  con- 
  

   sidered 
  as 
  untrue 
  or 
  false 
  atavism. 
  

  

  True 
  atavism, 
  or 
  reversion 
  caused 
  by 
  an 
  in- 
  

   nate 
  latent 
  tendency, 
  seems 
  to 
  be 
  very 
  rare, 
  

  

  