﻿Balanced 
  Crosses 
  301 
  

  

  two 
  groups 
  would 
  consist 
  of 
  thorn-bearing 
  and 
  

   thornless 
  plants, 
  in 
  the 
  same 
  numerical 
  relation. 
  

  

  * 
  

  

  Thus, 
  we 
  come 
  to 
  the 
  four 
  groups 
  observed 
  in 
  

   our 
  experiment, 
  and 
  are 
  able 
  to 
  calculate 
  their 
  

   relative 
  size 
  in 
  the 
  following 
  way 
  : 
  

  

  Proportion 
  

  

  Blue 
  with 
  thorns 
  3/4 
  X 
  3/4 
  = 
  9/16 
  = 
  56.25% 
  9 
  

  

  Blue, 
  unarmed 
  3/4 
  X 
  1/4 
  = 
  3/16 
  = 
  18.75% 
  3 
  

  

  White 
  with 
  thorns 
  1/4X3/4 
  = 
  3/16 
  = 
  18.75% 
  3 
  

  

  White, 
  unarmed 
  1/4 
  X 
  1/4 
  = 
  1/16 
  = 
  6.25% 
  1 
  

  

  In 
  order 
  to 
  compare 
  this 
  inference 
  from 
  Men- 
  

   del's 
  law 
  and 
  the 
  assumption 
  of 
  independency, 
  

   with 
  the 
  results 
  of 
  our 
  experiments, 
  we 
  must 
  cal- 
  

   culate 
  the 
  figures 
  of 
  the 
  latter 
  in 
  percentages. 
  

   In 
  this 
  way 
  we 
  find 
  : 
  

  

  Found. 
  Calculated. 
  

  

  Blue 
  with 
  thorns 
  128 
  = 
  51% 
  56.25% 
  

  

  Blue 
  unarmed 
  47 
  = 
  19% 
  18.75% 
  

  

  White 
  with 
  thorns. 
  ... 
  54 
  = 
  22% 
  18.75% 
  

  

  White 
  unarmed 
  21 
  = 
  8% 
  6.25% 
  

  

  The 
  agreement 
  of 
  the 
  experimental 
  and 
  the 
  

   theoretical 
  figures 
  is 
  as 
  close 
  as 
  might 
  be 
  

   expected. 
  

  

  This 
  experiment 
  is 
  to 
  be 
  considered 
  only 
  as 
  

   an 
  illustrative 
  example 
  of 
  a 
  rule 
  of 
  wide 
  appli- 
  

   cation. 
  The 
  rule 
  obviously 
  will 
  hold 
  good 
  in 
  

   all 
  such 
  cases 
  as 
  comply 
  with 
  the 
  two 
  conditions 
  

   already 
  premised, 
  viz. 
  : 
  that 
  each 
  character 
  

   agrees 
  with 
  Mendel's 
  law, 
  and 
  that 
  both 
  are 
  

   wholly 
  independent 
  of 
  each 
  other. 
  It 
  is 
  

   clear 
  that 
  our 
  figures 
  show 
  the 
  numerical 
  com- 
  

  

  