﻿Periodic 
  Mutations 
  703 
  

  

  fittest, 
  the 
  law 
  of 
  the 
  selection 
  of 
  species, 
  which 
  

   we 
  have 
  already 
  laid 
  stress 
  upon 
  more 
  than 
  

   once. 
  

  

  Our 
  second 
  consideration 
  is 
  also 
  based 
  upon 
  

   the 
  frequent 
  repetition 
  of 
  the 
  several 
  mutations. 
  

   Obviously 
  a 
  common 
  cause 
  must 
  prevail. 
  The 
  

   faculty 
  of 
  producing 
  nanella 
  or 
  lata 
  remains 
  the 
  

   same 
  through 
  all 
  the 
  years. 
  This 
  faculty 
  must 
  

   be 
  one 
  and 
  the 
  same 
  for 
  all 
  the 
  hundreds 
  of 
  mu- 
  

   tative 
  productions 
  of 
  the 
  same 
  form. 
  When 
  

   and 
  how 
  did 
  it 
  originate? 
  At 
  the 
  outset 
  it 
  must 
  

   have 
  been 
  produced 
  in 
  a 
  latent 
  condition, 
  and 
  

   even 
  yet 
  it 
  must 
  be 
  assumed 
  to 
  be 
  continuously 
  

   present 
  in 
  this 
  state, 
  and 
  only 
  to 
  become 
  active 
  

   at 
  distant 
  intervals. 
  But 
  it 
  is 
  manifest 
  that 
  

   the 
  original 
  production 
  of 
  the 
  characters 
  of 
  

   Oenothera 
  gigas 
  was 
  a 
  phenomenon 
  of 
  far 
  great- 
  

   er 
  importance 
  than 
  the 
  subsequent 
  accidental 
  

   transition 
  of 
  this 
  quality 
  into 
  the 
  active 
  state. 
  

   Hence 
  the 
  conclusion 
  that 
  at 
  the 
  beginning 
  of 
  

   each 
  series 
  of 
  analogous 
  mutations 
  there 
  must 
  

   have 
  been 
  one 
  greater 
  and 
  more 
  intrinsic 
  mu- 
  

   tation, 
  which 
  opened 
  the 
  possibility 
  to 
  all 
  its 
  

   successors. 
  This 
  was 
  the 
  origination 
  of 
  the 
  

   new 
  character 
  itself, 
  and 
  it 
  is 
  easily 
  seen 
  that 
  

   this 
  incipient 
  change 
  is 
  to 
  be 
  considered 
  as 
  the 
  

   real 
  one. 
  All 
  others 
  are 
  only 
  its 
  visible 
  ex- 
  

   pressions. 
  

  

  Considering 
  the 
  imitative 
  period 
  of 
  our 
  even- 
  

  

  