﻿692 
  Mutations 
  

  

  mutable 
  condition, 
  but 
  of 
  course 
  thousands 
  of 
  

   mutations 
  must 
  have 
  been 
  required 
  to 
  produce 
  

   the 
  evening-primroses 
  from 
  their 
  most 
  remote 
  

   ancestors. 
  

  

  If 
  we 
  take 
  the 
  species 
  into 
  consideration 
  

   that 
  are 
  not 
  mutable 
  at 
  present, 
  we 
  may 
  ask 
  

   how 
  we 
  are 
  to 
  harmonize 
  them 
  with 
  each 
  of 
  

   the 
  two 
  theories 
  proposed. 
  If 
  mutability 
  is 
  

   permanent, 
  it 
  is 
  manifest 
  that 
  the 
  whole 
  pedi- 
  

   gree 
  of 
  the 
  animal 
  and 
  vegetable 
  kingdom 
  is 
  to 
  

   be 
  considered 
  as 
  built 
  up 
  of 
  main 
  mutable 
  lines, 
  

   and 
  that 
  the 
  thousands 
  of 
  constant 
  species 
  can 
  

   only 
  be 
  taken 
  to 
  represent 
  lateral 
  branches 
  of 
  

   the 
  genealogic 
  tree. 
  

  

  These 
  lateral 
  branches 
  would 
  have 
  lost 
  the 
  

   capacity 
  of 
  mutating, 
  possessed 
  by 
  all 
  their 
  an- 
  

   cestors. 
  And 
  as 
  the 
  principle 
  of 
  the 
  hypothesis 
  

   under 
  discussion 
  does 
  not 
  allow 
  a 
  resumption 
  of 
  

   this 
  habit, 
  they 
  would 
  be 
  doomed 
  to 
  eternal 
  con- 
  

   stancy 
  until 
  they 
  finally 
  die 
  out. 
  Loss 
  of 
  muta- 
  

   bility, 
  under 
  this 
  conception, 
  means 
  loss 
  of 
  the 
  

   capacity 
  for 
  all 
  further 
  development. 
  Only 
  

   those 
  lines 
  of 
  the 
  main 
  pedigree 
  which 
  have 
  

   retained 
  this 
  capacity 
  would 
  have 
  a 
  future 
  ; 
  all 
  

   others 
  would 
  die 
  out 
  without 
  any 
  chance 
  of 
  pro- 
  

   gression. 
  

  

  If, 
  on 
  the 
  other 
  hand, 
  mutability 
  is 
  not 
  perma- 
  

   nent, 
  but 
  a 
  periodic 
  condition, 
  all 
  lines 
  of 
  the 
  

   genealogic 
  tree 
  must 
  be 
  assumed 
  to 
  show 
  alter- 
  

  

  