﻿502 
  Mutations 
  

  

  The 
  fact 
  that 
  the 
  origination 
  of 
  such 
  forms 
  

   is 
  accessible 
  to 
  direct 
  investigation 
  is 
  proven 
  

   quite 
  independently 
  of 
  all 
  further 
  considera- 
  

   tions. 
  The 
  new 
  variety 
  came 
  into 
  existence 
  at 
  

   once. 
  The 
  leap 
  may 
  have 
  been 
  made 
  by 
  the 
  

   ancestor 
  of 
  the 
  year 
  1895, 
  or 
  by 
  the 
  plant 
  of 
  

   1899, 
  which 
  showed 
  the 
  first 
  central 
  rays, 
  or 
  

   the 
  sport 
  may 
  have 
  been 
  gradually 
  built 
  up 
  dur- 
  

   ing 
  those 
  four 
  years. 
  In 
  each 
  case 
  there 
  was 
  a 
  

   leap, 
  contrasting 
  with 
  the 
  view 
  which 
  claims 
  a 
  

   very 
  long 
  succession 
  of 
  years 
  for 
  the 
  develop- 
  

   ment 
  of 
  every 
  new 
  character. 
  

  

  Having 
  discovered 
  this 
  first 
  trace 
  of 
  doubling, 
  

   it 
  was 
  to 
  be 
  expected 
  that 
  the 
  new 
  variety 
  would 
  

   be 
  at 
  once 
  as 
  pure 
  and 
  as 
  rich 
  as 
  other 
  double 
  

   composites 
  usually 
  are. 
  Some 
  effect 
  of 
  the 
  

   crossing 
  with 
  the 
  other 
  seed-bearing 
  individuals 
  

   might 
  still 
  disturb 
  this 
  uniformity 
  in 
  the 
  follow- 
  

   ing 
  year, 
  but 
  another 
  year's 
  work 
  would 
  elim- 
  

   inate 
  even 
  this 
  source 
  of 
  impurity. 
  

  

  These 
  two 
  years 
  have 
  given 
  the 
  expected 
  re- 
  

   sult. 
  The 
  average 
  number 
  of 
  the 
  rays, 
  which 
  

   had 
  already 
  arisen 
  from 
  13 
  to 
  34 
  now 
  at 
  once 
  

   came 
  up 
  to 
  47 
  and 
  55, 
  the 
  last 
  figure 
  being 
  the 
  

   sum 
  of 
  21 
  and 
  34 
  and 
  therefore 
  the 
  probable 
  

   uttermost 
  limit 
  to 
  be 
  reached 
  before 
  absolute 
  

   doubling. 
  The 
  maximum 
  numbers 
  came 
  as 
  high 
  

   as 
  100 
  in 
  1900, 
  and 
  reached 
  even 
  200 
  in 
  1901. 
  

   Such 
  heads 
  are 
  as 
  completely 
  double 
  as 
  are 
  the 
  

  

  