﻿562 
  Mutations 
  

  

  which 
  of 
  them 
  was 
  the 
  progenitor 
  of 
  the 
  others 
  ? 
  

   Of 
  course 
  this 
  could 
  be 
  done 
  by 
  long 
  and 
  tedious 
  

   crossing-experiments, 
  showing 
  atavism 
  in 
  the 
  

   progeny, 
  and 
  thereby 
  indicating 
  the 
  common 
  

   ancestor. 
  But 
  even 
  this 
  capacity 
  seems 
  to 
  be 
  

   doubtful 
  and 
  connected 
  only 
  with 
  the 
  state 
  of 
  

   mutability 
  and 
  to 
  be 
  lost 
  afterwards. 
  Therefore 
  

   if 
  this 
  period 
  of 
  mutation 
  were 
  ended, 
  probably 
  

   there 
  would 
  be 
  no 
  way 
  to 
  decide 
  concerning 
  the 
  

   mutual 
  relationship 
  of 
  the 
  single 
  species. 
  

  

  Hence 
  the 
  lack 
  of 
  a 
  recognizable 
  main 
  stem 
  in 
  

   swarms 
  of 
  elementary 
  species 
  makes 
  it 
  impossi- 
  

   ble 
  to 
  answer 
  the 
  question 
  concerning 
  their 
  com- 
  

   mon 
  origin. 
  

  

  Another 
  phase 
  of 
  the 
  opposition 
  between 
  the 
  

   prevailing 
  view 
  and 
  my 
  own 
  results 
  seems 
  far 
  

   more 
  important. 
  According 
  to 
  the 
  current 
  be- 
  

   lief 
  the 
  conversion 
  of 
  a 
  group 
  of 
  plants 
  growing 
  

   in 
  any 
  locality 
  and 
  flowering 
  simultaneously 
  

   would 
  be 
  restricted 
  to 
  one 
  type. 
  In 
  my 
  own 
  ex- 
  

   periments 
  several 
  new 
  species 
  arose 
  from 
  the 
  

   parental 
  form 
  at 
  once, 
  giving 
  a 
  wide 
  range 
  of 
  

   new 
  forms 
  at 
  the 
  same 
  time 
  and 
  under 
  the 
  same 
  

   conditions. 
  

  

  III. 
  New 
  elementary 
  species 
  attain 
  their 
  full 
  

   constancy 
  at 
  once. 
  

  

  Constancy 
  is 
  not 
  the 
  result 
  of 
  selection 
  or 
  of 
  

   improvement. 
  It 
  is 
  a 
  quality 
  of 
  its 
  own. 
  It 
  can 
  

   neither 
  be 
  constrained 
  bv 
  selection 
  if 
  it 
  is 
  absent 
  

  

  