﻿False 
  Atavism 
  205 
  

  

  immediately 
  have 
  been 
  observed, 
  had 
  it 
  oc- 
  

   curred, 
  because 
  the 
  hybrids 
  between 
  the 
  cruci- 
  

   ate 
  and 
  the 
  normal 
  flowers 
  are 
  not 
  intermediate, 
  

   but 
  bear 
  the 
  broad 
  petals 
  of 
  the 
  0. 
  biennis. 
  

  

  We 
  may 
  now 
  take 
  up 
  another 
  phase 
  of 
  the 
  

   question, 
  that 
  of 
  the 
  running 
  out 
  of 
  new 
  varie- 
  

   ties, 
  shortly 
  after 
  their 
  introduction 
  into 
  a 
  new 
  

   country, 
  or 
  later. 
  

  

  The 
  most 
  widely 
  known 
  instance 
  of 
  this 
  is 
  

   that 
  of 
  the 
  American 
  corn 
  in 
  Baden, 
  recorded 
  

   by 
  Metzger 
  and 
  quoted 
  by 
  Darwin 
  as 
  a 
  remark- 
  

   able 
  instance 
  of 
  the 
  direct 
  and 
  prompt 
  action 
  

   of 
  climate 
  on 
  a 
  plant. 
  It 
  has 
  since 
  been 
  con- 
  

   sidered 
  as 
  a 
  reversion 
  to 
  the 
  old 
  type. 
  Such 
  

   reversions 
  invariably 
  occur, 
  according 
  to 
  Wal- 
  

   lace, 
  in 
  cases 
  of 
  new 
  varieties, 
  which 
  have 
  

   been 
  produced 
  quickly. 
  But 
  as 
  we 
  now 
  know, 
  

   such 
  reversions 
  are 
  due 
  to 
  spontaneous 
  crosses 
  

   with 
  the 
  old 
  form, 
  and 
  to 
  the 
  rule, 
  that 
  the 
  

   hybrids 
  of 
  such 
  origin 
  are 
  not 
  intermediate, 
  

   but 
  assume 
  the 
  features 
  of 
  the 
  older 
  of 
  the 
  

   two 
  parents. 
  In 
  the 
  light 
  of 
  this 
  experience, 
  

   Metzger 
  's 
  observation 
  becomes 
  a 
  typical 
  in- 
  

   stance 
  of 
  vicinism. 
  It 
  relates 
  to 
  the 
  " 
  Tusca- 
  

   rora 
  " 
  corn 
  of 
  St. 
  Louis, 
  a 
  variety 
  with 
  broad 
  

   and 
  flat 
  white 
  seeds. 
  

  

  About 
  the 
  year 
  1840, 
  this 
  corn 
  was 
  introduced 
  

   into 
  Baden 
  in 
  Germany, 
  and 
  cultivated 
  by 
  Metz- 
  

   ger. 
  In 
  the 
  first 
  year 
  it 
  came 
  true 
  to 
  type, 
  and 
  

  

  