﻿AND 
  STARCH 
  CHARACTERS 
  IN 
  CORN 
  173 
  

  

  evidence 
  for 
  pairing 
  of 
  the 
  homologous 
  chromosomes 
  from 
  the 
  two 
  

  

  m 
  

  

  parents 
  as 
  indicated 
  by 
  length 
  and 
  other 
  differential 
  characters 
  is 
  

   accumulating 
  rapidly 
  both 
  for 
  plants 
  and 
  animals. 
  For 
  data 
  as 
  to 
  

   plant 
  material 
  see 
  Strasburger 
  ('05), 
  Stomps 
  ('10) 
  and 
  Clemens 
  

   Miiller 
  ('09 
  and 
  '12). 
  

  

  While 
  we 
  need 
  more 
  convincing 
  proof 
  of 
  the 
  relationship 
  of 
  

  

  1 
  

  

  the 
  processes 
  in 
  the 
  so-called 
  first 
  and 
  second 
  divisions 
  to 
  the 
  process 
  

   of 
  the 
  reduction 
  of 
  the 
  chromosome 
  number 
  there 
  can 
  be 
  no 
  

   question 
  now 
  that 
  in 
  general 
  the 
  sporophyte 
  is 
  a 
  double 
  or 
  com- 
  

   bination 
  individual 
  and 
  that 
  the 
  chromosomes 
  contributed 
  by 
  

   its 
  tW'O 
  parents 
  maintain 
  a 
  sort 
  of 
  individuality 
  even 
  when 
  so 
  

  

  combined. 
  

  

  Cytological 
  evidence 
  is 
  as 
  yet 
  quite 
  lacking 
  as 
  to 
  just 
  when 
  and 
  

   how 
  in 
  fertiHzation 
  or 
  in 
  the 
  succeeding 
  divisions 
  the 
  homologous 
  

   chromosomes 
  are 
  able 
  to 
  find 
  each 
  other 
  out 
  and 
  attain 
  the 
  paired 
  

   relationships 
  which 
  the 
  sporophytic 
  division 
  figures 
  show 
  so 
  

   clearly. 
  Sax 
  ('i8) 
  reports 
  for 
  Fritillaria 
  and 
  Triticum 
  that 
  they 
  

   do 
  not 
  pair 
  in 
  the 
  first 
  division 
  of 
  the 
  fertilized 
  egg. 
  Resort 
  to 
  

   conceptions 
  of 
  chemical 
  affinity, 
  magnetic 
  polarities, 
  etc., 
  are 
  of 
  

   course 
  useless 
  here 
  and 
  our 
  best 
  suggestions, 
  as 
  it 
  seems 
  to 
  me, 
  are 
  

   found 
  in 
  the 
  conception 
  of 
  permanent 
  connections 
  or 
  space 
  relations 
  

   between 
  chromosomes 
  and 
  the 
  mechanically 
  active 
  kinoplasmic 
  

   elements 
  of 
  the 
  colloidal 
  cell 
  organization 
  which 
  are 
  indicated 
  in 
  

   Rabl's 
  figure 
  ('89), 
  the 
  constant 
  relations 
  between 
  centrosome 
  and 
  

   nucleus 
  observed 
  bv 
  Conklin 
  in 
  Crepidula 
  ('02) 
  and 
  the 
  visibly 
  

  

  between 
  

  

  mosomes 
  

  

  The 
  pairing 
  of 
  the 
  germ 
  cells 
  with 
  each 
  new 
  fertilization 
  is 
  

   determined 
  by 
  the 
  external 
  environment 
  and 
  is 
  a 
  matter 
  of 
  chance, 
  

   but 
  the 
  homologous 
  chromosomes 
  of 
  each 
  probably 
  become 
  paired 
  

   through 
  the 
  mechanical 
  activities 
  made 
  possible 
  by 
  the 
  cell 
  organi- 
  

   zation 
  constituting 
  the 
  interna! 
  environment 
  of 
  the 
  cell 
  elements. 
  

  

  We 
  

  

  been 
  

  

  possible, 
  though 
  the 
  assumption 
  of 
  an 
  effective 
  internal 
  environ- 
  

  

  necessary 
  

  

  However 
  the 
  pairing 
  may 
  be 
  brought 
  about, 
  there 
  is 
  general 
  

   agreement 
  that 
  it 
  has 
  been 
  achieved 
  completely 
  at 
  synapsis 
  and 
  

  

  