﻿702 
  Mutations 
  

  

  thera 
  brevistylis. 
  Most 
  of 
  the 
  others 
  quickly 
  

   disappear. 
  

  

  This 
  failure 
  of 
  a 
  large 
  part 
  of 
  the 
  productions 
  

   of 
  nature 
  deserves 
  to 
  be 
  considered 
  at 
  some 
  

   length. 
  It 
  may 
  be 
  elevated 
  to 
  a 
  principle, 
  and 
  

   may 
  be 
  made 
  use 
  of 
  to 
  explain 
  many 
  diffi- 
  

   cult 
  points 
  of 
  the 
  theory 
  of 
  descent. 
  If, 
  in 
  

   order 
  to 
  secure 
  one 
  good 
  novelty, 
  nature 
  must 
  

   produce 
  ten 
  or 
  twenty 
  or 
  perhaps 
  more 
  bad 
  

   ones 
  at 
  the 
  same 
  time, 
  the 
  possibility 
  of 
  im- 
  

   provements 
  coming 
  by 
  pure 
  chance 
  must 
  be 
  

   granted 
  at 
  once. 
  All 
  hypotheses 
  concerning 
  the 
  

   direct 
  causes 
  of 
  adaptation 
  at 
  once 
  become 
  su- 
  

   perfluous, 
  and 
  the 
  great 
  principle 
  enunciated 
  by 
  

   Darwin 
  once 
  more 
  reigns 
  supreme. 
  

  

  In 
  this 
  way 
  too, 
  the 
  mutation-period 
  of 
  the 
  

   evening-primrose 
  is 
  to 
  be 
  considered 
  as 
  a 
  proto- 
  

   type. 
  Assuming 
  it 
  as 
  such 
  provisionally, 
  it 
  may 
  

   aid 
  us 
  in 
  arranging 
  the 
  facts 
  of 
  descent 
  so 
  as 
  to 
  

   allow 
  of 
  a 
  deeper 
  insight 
  and 
  a 
  closer 
  scrutiny. 
  

   All 
  swarms 
  of 
  elementary 
  species 
  are 
  the 
  re- 
  

   mains 
  of 
  far 
  larger 
  initial 
  groups. 
  All 
  species 
  

   containing 
  only 
  a 
  few 
  subspecies 
  may 
  be 
  sup- 
  

   posed 
  to 
  have 
  thrown 
  off 
  at 
  the 
  outset 
  far 
  more 
  

   numerous 
  lateral 
  branches, 
  out 
  of 
  which 
  how- 
  

   ever, 
  the 
  greater 
  part 
  have 
  been 
  lost, 
  being 
  

   unfit 
  for 
  the 
  surrounding 
  conditions. 
  It 
  is 
  

   the 
  principle 
  of 
  the 
  struggle 
  for 
  life 
  between 
  ele- 
  

   mentary 
  species, 
  followed 
  by 
  the 
  survival 
  of 
  the 
  

  

  