﻿188 
  Prof. 
  W. 
  Bateson 
  and 
  Miss 
  C. 
  Pellew. 
  The 
  Genetics 
  of 
  

  

  belonging 
  to 
  families 
  which, 
  had 
  been 
  selected 
  as 
  being 
  the 
  most 
  rogue-free.* 
  

   Since, 
  thus 
  fertilised, 
  every 
  egg-cell 
  genetically 
  rogue, 
  will 
  produce 
  a 
  rogue, 
  

   and 
  every 
  egg-cell 
  genetically 
  type 
  will 
  produce 
  a 
  type, 
  the 
  resulting 
  family, 
  

   sown 
  in 
  order, 
  will 
  show 
  the 
  distribution 
  of 
  the 
  rogue- 
  and 
  type-characters 
  

   among 
  the 
  egg- 
  cells 
  of 
  the 
  intermediate 
  parent. 
  The 
  seeds 
  from 
  each 
  pod 
  

   were 
  sown 
  separately, 
  and 
  we 
  expected 
  to 
  find 
  that 
  the 
  non-pointed 
  would 
  

   come 
  almost 
  exclusively 
  from 
  the 
  lowest 
  pods. 
  This 
  expectation, 
  however, 
  

   was 
  not 
  borne 
  out 
  by 
  the 
  result, 
  for 
  the 
  proportion 
  of 
  non-pointed 
  among 
  the 
  

   egg-cells 
  did 
  not 
  diminish 
  noticeably 
  at 
  least 
  up 
  to 
  the 
  tenth 
  flower. 
  Since 
  

   the 
  same 
  plants, 
  if 
  self 
  -fertilised, 
  very 
  rarely 
  produce 
  a 
  non-pointed 
  plant 
  

   from 
  flowers 
  higher 
  than 
  the 
  fourth, 
  a 
  presumption 
  was 
  raised 
  that 
  the 
  male 
  

   and 
  female 
  sides 
  must 
  be 
  differently 
  constituted, 
  and 
  that 
  the 
  proportion 
  of 
  

   pointed 
  gametes 
  would 
  be 
  found 
  to 
  change 
  with 
  the 
  level 
  much 
  more 
  rapidly 
  

   on 
  the 
  male 
  side. 
  Tests 
  were 
  therefore 
  instituted, 
  using 
  pollen 
  of 
  the 
  

   successive 
  flowers 
  of 
  the 
  intermediate 
  plants 
  and 
  trying 
  it 
  on 
  the 
  ovules 
  

   of 
  types. 
  The 
  experiment 
  has 
  not 
  been 
  made 
  on 
  a 
  scale 
  sufficient 
  to 
  

   determine 
  the 
  true 
  average 
  ratios 
  of 
  non-pointed 
  to 
  pointed 
  in 
  successive 
  

   flowers, 
  but 
  that 
  the 
  proportion 
  of 
  pointed 
  increases 
  rapidly 
  from 
  about 
  the 
  

   third 
  flower 
  is 
  clearly 
  proved. 
  

  

  Work 
  of 
  this 
  kind 
  is 
  exceedingly 
  laborious, 
  and 
  the 
  wastage 
  from 
  various 
  

   causes 
  must 
  inevitably 
  be 
  very 
  large. 
  Of 
  the 
  plants 
  chosen 
  for 
  operation 
  

   some 
  necessarily 
  prove 
  to 
  be 
  of 
  the 
  wrong 
  kinds, 
  throwing, 
  for 
  example, 
  all 
  

   rogues 
  and 
  all 
  the 
  work 
  done 
  on 
  such 
  plants 
  turns 
  out 
  in 
  the 
  following 
  year 
  

   to 
  be 
  inapplicable. 
  We 
  considered 
  ourselves 
  fairly 
  fortunate 
  in 
  having 
  raised 
  

   1016 
  cross-bred 
  plants 
  from 
  which 
  to 
  estimate 
  the 
  output 
  of 
  the 
  female 
  

   side, 
  and 
  468 
  plants 
  derived 
  from 
  the 
  male 
  side 
  of 
  the 
  pointed 
  intermediates, 
  

   together 
  with 
  1572 
  plants 
  from 
  flowers 
  of 
  known 
  position 
  self-fertilised.f 
  

   The 
  results 
  are 
  set 
  out 
  in 
  Table 
  I, 
  where 
  the 
  actual 
  numbers 
  from 
  each 
  

   flower 
  are 
  given 
  with 
  the 
  ratios 
  deduced 
  from 
  them. 
  As 
  to 
  the 
  female 
  side 
  

   of 
  the 
  flowers 
  the 
  evidence 
  may 
  be 
  regarded 
  as 
  significant 
  up 
  to 
  the 
  14th 
  

   flower. 
  The 
  proportion 
  of 
  non-pointed 
  female 
  gametes 
  remains 
  about 
  con- 
  

   stant 
  at 
  a 
  ratio 
  of 
  rather 
  more 
  than 
  1 
  in 
  2 
  up 
  to 
  the 
  tenth 
  flower, 
  above 
  

   which 
  it 
  diminishes. 
  On 
  the 
  male 
  side 
  the 
  proportion 
  of 
  non-pointed 
  

   gametes 
  is 
  about 
  1 
  in 
  5 
  for 
  the 
  first 
  two 
  flowers 
  and 
  then 
  drops 
  sharply 
  and 
  

  

  * 
  The 
  proportion 
  of 
  rogues 
  (or, 
  more 
  strictly, 
  pointed) 
  thrown 
  by 
  ordinary 
  types 
  is, 
  

   in 
  our 
  experience, 
  about 
  2 
  per 
  cent. 
  In 
  the 
  purer 
  type-families 
  selected 
  for 
  crossing 
  

   the 
  percentage 
  would 
  be 
  even 
  lower 
  than 
  this, 
  so 
  that 
  for 
  practical 
  purposes 
  they 
  may 
  

   be 
  regarded 
  as 
  rogue-free. 
  

  

  t 
  An 
  attempt 
  was 
  made 
  on 
  a 
  considerable 
  scale, 
  by 
  sowing 
  the 
  peas 
  of 
  each 
  pod 
  in 
  

   their 
  original 
  order, 
  to 
  test 
  whether 
  there 
  is 
  any 
  orderly 
  arrangement 
  of 
  the 
  seeds. 
  

   This 
  work, 
  which 
  added 
  greatly 
  to 
  our 
  task, 
  led 
  to 
  no 
  positive 
  result. 
  

  

  