﻿Selection 
  of 
  Elementary 
  Species 
  93 
  

  

  duction 
  of 
  sugar. 
  He 
  must 
  have 
  made 
  some 
  

   choice 
  among 
  the 
  numerous 
  available 
  sorts 
  of 
  

   beets, 
  or 
  chance 
  must 
  have 
  placed 
  in 
  his 
  hands 
  

   one 
  of 
  the 
  most 
  appropriate 
  forms. 
  On 
  this 
  

   point 
  however, 
  no 
  evidence 
  is 
  at 
  hand. 
  

  

  Since 
  the 
  work 
  of 
  Vilmorin 
  the 
  selection-prin- 
  

   ciple 
  has 
  increased 
  enormously 
  in 
  importance, 
  

   for 
  practical 
  purposes 
  as 
  well 
  as 
  for 
  the 
  the- 
  

   oretical 
  aspect 
  of 
  the 
  subject. 
  It 
  is 
  now 
  being 
  

   applied 
  on 
  a 
  large 
  scale 
  to 
  nearly 
  all 
  ornamental 
  

   plants. 
  It 
  is 
  the 
  one 
  great 
  principle 
  now 
  in 
  

   universal 
  practice 
  as 
  well 
  as 
  one 
  of 
  preeminent 
  

   scientific 
  value. 
  Of 
  course, 
  the 
  main 
  argu- 
  

   ments 
  of 
  the 
  evolution 
  theory 
  rest 
  upon 
  mor- 
  

   phologic, 
  systematic, 
  geographic 
  and 
  pale- 
  

   ontologic 
  evidence. 
  But 
  the 
  question 
  as 
  to 
  how 
  

   we 
  can 
  coordinate 
  the 
  relation 
  between 
  

   existing 
  species 
  and 
  their 
  supposed 
  ancestors 
  

   is 
  of 
  course 
  one 
  of 
  a 
  physiologic 
  nature. 
  Di- 
  

   rect 
  observation 
  or 
  experiments 
  were 
  not 
  avail- 
  

   able 
  for 
  Darwin 
  and 
  so 
  he 
  found 
  himself 
  con- 
  

   strained 
  to 
  make 
  use 
  of 
  the 
  experience 
  of 
  breed- 
  

   ers. 
  This 
  he 
  did 
  on 
  a 
  broad 
  scale, 
  and 
  with 
  

   such 
  success 
  that 
  it 
  was 
  precisely 
  this 
  side 
  of 
  

   his 
  arguments 
  that 
  played 
  the 
  major 
  part 
  in 
  

   convincing 
  his 
  contemporaries. 
  

  

  The 
  work 
  of 
  the 
  breeders 
  previous 
  to 
  Dar- 
  

   win's 
  time 
  had 
  not 
  been 
  very 
  critically 
  per- 
  

   formed. 
  Eecent 
  analvses 
  of 
  the 
  evidence 
  ob- 
  

  

  