﻿198 
  Retrograde 
  Varieties 
  

  

  improvement 
  as 
  may 
  be 
  obtained 
  with 
  a 
  mini- 
  

   mum 
  of 
  cost, 
  and 
  this 
  mostly 
  implies 
  a 
  culture 
  in 
  

   the 
  same 
  part 
  of 
  the 
  nursery 
  with 
  older 
  varie- 
  

   ties 
  of 
  the 
  same 
  species. 
  Three, 
  four 
  or 
  five 
  

   years 
  are 
  required 
  to 
  purify 
  the 
  novelty, 
  and 
  

   as 
  this 
  same 
  length 
  of 
  time 
  is 
  also 
  required 
  to 
  

   produce 
  sufficient 
  quantities 
  of 
  seed 
  for 
  

   commercial 
  purposes, 
  there 
  is 
  no 
  strong 
  

   desire 
  to 
  shorten 
  the 
  period 
  of 
  selection 
  and 
  

   fixation. 
  I 
  had 
  occasion 
  to 
  see 
  this 
  process 
  go- 
  

   ing 
  on 
  with 
  sundry 
  novelties 
  at 
  Erfurt 
  in 
  

   Germany. 
  Among 
  them 
  a 
  chamois-colored 
  va- 
  

   riety 
  of 
  the 
  common 
  stock, 
  a 
  bluish 
  Clarkia 
  

   elegans 
  and 
  a 
  curiously 
  colored 
  opium-poppy 
  

   may 
  be 
  mentioned. 
  In 
  some 
  cases 
  the 
  cross- 
  

   fertilization 
  is 
  so 
  overwhelming, 
  that 
  in 
  the 
  

   next 
  generation 
  the 
  novelty 
  seems 
  entirely 
  to 
  

   have 
  disappeared. 
  

  

  The 
  examples 
  given 
  may 
  suffice 
  to 
  convey 
  a 
  

   general 
  idea 
  of 
  the 
  phenomenon, 
  ordinarily 
  

   called 
  atavism 
  by 
  gardeners, 
  and 
  considered 
  

   mostly 
  to 
  be 
  the 
  effect 
  of 
  some 
  innate 
  tendency 
  

   to 
  revert 
  to 
  the 
  ancestral 
  form. 
  It 
  is 
  on 
  this 
  

   conception 
  that 
  the 
  almost 
  universal 
  belief 
  

   rests, 
  that 
  varieties 
  are 
  distinguished, 
  as 
  such, 
  

   from 
  species 
  by 
  their 
  inconstancy. 
  Now 
  I 
  do 
  

   not 
  deny 
  the 
  phenomenon 
  itself. 
  The 
  impurity 
  

   of 
  seeds 
  and 
  cultures 
  is 
  so 
  general 
  and 
  so 
  mani- 
  

   fest, 
  and 
  may 
  so 
  easily 
  be 
  tested 
  by 
  every 
  one 
  

  

  