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  Retrograde 
  Varieties 
  

  

  yielding 
  new, 
  and 
  very 
  often, 
  valuable 
  varieties. 
  

   But 
  it 
  is 
  manifest 
  that 
  this 
  form 
  of 
  variation 
  

   is 
  of 
  quite 
  another 
  nature 
  from 
  the 
  variations 
  

   of 
  pure 
  races. 
  Many 
  hybrid 
  varieties 
  are 
  quite 
  

   constant, 
  and 
  remain 
  true 
  to 
  their 
  type 
  if 
  no 
  

   further 
  crosses 
  are 
  made 
  ; 
  many 
  others 
  are 
  arti- 
  

   ficially 
  propagated 
  only 
  in 
  a 
  vegetative 
  way, 
  

   and 
  for 
  this 
  reason 
  are 
  always 
  found 
  true. 
  

   Hybrid 
  varieties 
  as 
  a 
  rule 
  were 
  formerly 
  con- 
  

   fused 
  with 
  pure 
  varieties, 
  and 
  in 
  many 
  in- 
  

   stances 
  our 
  knowledge 
  as 
  to 
  their 
  origin 
  is 
  quite 
  

   insufficient 
  for 
  sharp 
  distinctions. 
  To 
  every 
  

   student 
  of 
  nature 
  it 
  is 
  obvious, 
  that 
  crossing 
  

   and 
  pure 
  variability 
  are 
  wholly 
  distinct 
  groups 
  

   of 
  phenomena, 
  which 
  should 
  never 
  be 
  treated 
  

   under 
  the 
  same 
  head, 
  or 
  under 
  the 
  same 
  name. 
  

   Leaving 
  aside 
  polymorphy, 
  we 
  may 
  now 
  dis- 
  

   cuss 
  those 
  cases 
  of 
  variability, 
  in 
  which 
  the 
  

   changes 
  themselves, 
  and 
  not 
  only 
  their 
  final 
  

   results 
  play 
  a 
  part. 
  Of 
  such 
  changes 
  two 
  types 
  

   exist. 
  First, 
  the 
  ever-recurring 
  variability, 
  

   never 
  absent 
  in 
  any 
  large 
  group 
  of 
  individuals, 
  

   and 
  determining 
  the 
  differences 
  which 
  are 
  al- 
  

   ways 
  to 
  be 
  seen 
  between 
  parents 
  and 
  their 
  

   children, 
  or 
  between 
  the 
  children 
  themselves. 
  

   This 
  type 
  is 
  commonly 
  called 
  " 
  individual 
  

   variability 
  " 
  and 
  since 
  this 
  term 
  also 
  has 
  still 
  

   other 
  meanings, 
  it 
  has 
  of 
  late 
  become 
  customary 
  

   to 
  use 
  instead 
  the 
  term 
  " 
  fluctuating 
  varia- 
  

  

  