﻿LECTURE 
  XX 
  

  

  THE 
  ORIGIN 
  OF 
  WILD 
  SPECIES 
  AND 
  VARIETIES 
  

  

  New 
  species 
  and 
  varieties 
  occur 
  from 
  time 
  to 
  

   time 
  in 
  the 
  wild 
  state. 
  Setting 
  aside 
  all 
  theo- 
  

   retical 
  conceptions 
  as 
  to 
  the 
  common 
  origin 
  of 
  

   species 
  at 
  large, 
  the 
  undoubted 
  fact 
  remains 
  that 
  

   new 
  forms 
  are 
  sometimes 
  met 
  with. 
  In 
  the 
  case 
  

   of 
  the 
  peloric 
  toad-flax 
  the 
  mutations 
  are 
  so 
  

   numerous 
  that 
  they 
  seem 
  to 
  be 
  quite 
  regular. 
  

   The 
  production 
  of 
  new 
  species 
  of 
  evening-prim- 
  

   roses 
  was 
  observed 
  on 
  the 
  field 
  and 
  afterwards 
  

   duplicated 
  in 
  the 
  garden. 
  There 
  is 
  no 
  reason 
  

   to 
  think 
  that 
  these 
  cases 
  are 
  isolated 
  instances. 
  

   Quite 
  on 
  the 
  contrary 
  they 
  seem 
  to 
  be 
  the 
  pro- 
  

   totypes 
  of 
  repeated 
  occurrences 
  in 
  nature. 
  

  

  If 
  this 
  conception 
  is 
  granted, 
  the 
  question 
  at 
  

   once 
  arises, 
  how 
  are 
  we 
  to 
  deal 
  with 
  analogous 
  

   cases, 
  when 
  fortune 
  offers 
  them, 
  and 
  what 
  can 
  

   we 
  expect 
  to 
  learn 
  from 
  them? 
  

  

  A 
  critical 
  study 
  of 
  the 
  existing 
  evidence 
  seems 
  

   to 
  be 
  of 
  great 
  importance 
  in 
  order 
  to 
  ascertain 
  

   the 
  best 
  way 
  of 
  dealing 
  with 
  new 
  facts, 
  and 
  of 
  

   estimating 
  the 
  value 
  of 
  the 
  factors 
  concerned. 
  

  

  576 
  

  

  