﻿False 
  Atavism 
  189 
  

  

  types 
  are 
  themselves 
  quite 
  stable, 
  or 
  when 
  it 
  is 
  

   not 
  at 
  all 
  intended 
  to 
  raise 
  the 
  question 
  of 
  their 
  

   stability. 
  In 
  scientific 
  works 
  it 
  is 
  commonly 
  

   used 
  to 
  designate 
  the 
  occurrence 
  of 
  subspecies 
  

   or 
  varieties, 
  and 
  the 
  same 
  is 
  the 
  case 
  in 
  the 
  

   ordinary 
  use 
  of 
  the 
  term 
  when 
  dealing 
  with 
  

   cultivated 
  plants. 
  A 
  species 
  may 
  consist 
  of 
  

   larger 
  or 
  smaller 
  groups 
  of 
  such 
  units, 
  and 
  

   they 
  may 
  be 
  absolutely 
  constant, 
  never 
  sport- 
  

   ing 
  if 
  hybridization 
  is 
  precluded, 
  and 
  neverthe- 
  

   less 
  it 
  may 
  be 
  called 
  highly 
  variable. 
  The 
  

   opium-poppy 
  affords 
  a 
  good 
  instance. 
  It 
  

   " 
  varies 
  " 
  in 
  height, 
  in 
  color 
  of 
  foliage 
  and 
  

   flowers 
  ; 
  the 
  last 
  are 
  often 
  double 
  or 
  laciniated 
  ; 
  

   it 
  may 
  have 
  white 
  or 
  bluish 
  seeds, 
  the 
  capsules 
  

   may 
  open 
  themselves 
  or 
  remain 
  closed 
  and 
  so 
  

   on. 
  But 
  every 
  single 
  variety 
  is 
  absolutely 
  con- 
  

   stant, 
  and 
  never 
  runs 
  into 
  another, 
  when 
  the 
  

   flowers 
  are 
  artificially 
  pollinated 
  and 
  the 
  visits 
  

   of 
  insects 
  excluded. 
  So 
  it 
  is 
  with 
  many 
  other 
  

   species. 
  They 
  are 
  at 
  the 
  same 
  time 
  wholly 
  

   stable 
  and 
  very 
  variable. 
  

  

  The 
  terms 
  variation 
  and 
  variety 
  are 
  used 
  

   frequently 
  when 
  speaking 
  of 
  hybrids. 
  By 
  cross- 
  

   ing 
  forms, 
  which 
  are 
  already 
  variable 
  in 
  the 
  

   sense 
  just 
  mentioned, 
  it 
  is 
  easy 
  to 
  multiply 
  the 
  

   number 
  of 
  the 
  types, 
  and 
  even 
  in 
  crossing 
  pure 
  

   forms 
  the 
  different 
  characters 
  may 
  be 
  combined 
  

   in 
  different 
  ways, 
  the 
  resulting 
  combinations 
  

  

  