﻿226 
  Retrograde 
  Varieties 
  

  

  tematist, 
  Alphonse 
  De 
  Candolle, 
  we 
  may 
  now 
  

   try 
  to 
  give 
  the 
  proofs 
  of 
  our 
  assertion, 
  by 
  using 
  

   only 
  those 
  instances 
  that 
  have 
  been 
  thoroughly 
  

   tested 
  in 
  every 
  way. 
  

  

  We 
  may 
  at 
  once 
  proceed 
  to 
  the 
  retrogressive 
  

   or 
  negative 
  varieties. 
  The 
  arguments 
  for 
  the 
  

   assumption 
  that 
  elementary 
  species 
  owe 
  their 
  

   origin 
  to 
  the 
  acquisition 
  of 
  new 
  qualities 
  may 
  

   well 
  be 
  left 
  for 
  later 
  lectures 
  when 
  we 
  shall 
  

   deal 
  with 
  the 
  experimental 
  proofs 
  in 
  this 
  mat- 
  

   ter. 
  

  

  There 
  are 
  three 
  larger 
  groups 
  of 
  facts, 
  on 
  

   which 
  the 
  assumption 
  of 
  latent 
  characters 
  in 
  

   ordinary 
  varieties 
  rests. 
  These 
  are 
  true 
  ata- 
  

   vism, 
  incomplete 
  loss 
  of 
  characters, 
  and 
  system- 
  

   atic 
  affinity. 
  Before 
  dealing 
  with 
  each 
  of 
  these 
  

   separately, 
  it 
  may 
  be 
  as 
  well 
  to 
  recall 
  once 
  more 
  

   that 
  in 
  former 
  lectures 
  we 
  have 
  treated 
  the 
  

   apparent 
  losses 
  only 
  as 
  modifications 
  in 
  a 
  

   negative 
  way, 
  without 
  contemplating 
  the 
  under- 
  

   lying 
  causes. 
  

  

  Let 
  us 
  recall 
  the 
  cases 
  of 
  bud-atavism 
  given 
  

   by 
  the 
  whitish 
  variety 
  of 
  the 
  scarlet 
  Ribes, 
  by 
  

   peaches 
  and 
  nectarines, 
  and 
  by 
  conifers, 
  includ- 
  

   ing 
  Cephalotaxus 
  and 
  Cryptomeria. 
  These 
  and 
  

   many 
  other 
  analogous 
  facts 
  go 
  to 
  prove 
  the 
  re- 
  

   lation 
  of 
  the 
  variety 
  to 
  the 
  species. 
  Two 
  as- 
  

   sumptions 
  are 
  allowable. 
  In 
  one 
  the 
  variety 
  

   differs 
  from 
  the 
  species 
  by 
  the 
  total 
  loss 
  of 
  the 
  

  

  