﻿516 
  J. 
  BBETLAND 
  FARMElt 
  AND 
  J. 
  E. 
  S. 
  MOORE. 
  

  

  that 
  a 
  true 
  reduction 
  division 
  was 
  associated 
  with 
  this 
  par- 
  

   ticular 
  karyokinesis. 
  After 
  what 
  has 
  been 
  said 
  it 
  will, 
  how- 
  

   ever, 
  be 
  clear 
  that 
  there 
  is 
  no 
  real 
  difference 
  between 
  the 
  

   two 
  cases, 
  but 
  that 
  the 
  second 
  (horaotype) 
  mitosis 
  results 
  in 
  

   the 
  separation 
  of 
  the 
  longitudinal 
  halves 
  of 
  the 
  original 
  

   spireme 
  thread 
  that 
  by 
  their 
  partial 
  divergence 
  have 
  already 
  

   given 
  rise 
  to 
  the 
  figures 
  of 
  V 
  and 
  /^ 
  duringthe 
  previous 
  diaster. 
  

  

  Since 
  the 
  preceding 
  account 
  of 
  the 
  heterotype 
  and 
  homo- 
  

   type 
  mitoses 
  in 
  L 
  ilium 
  was 
  written, 
  af 
  paper 
  has 
  appeared 
  

   from 
  the 
  pen 
  of 
  Professor 
  Gregoire 
  ^ 
  in 
  which 
  he 
  contests 
  the 
  

   correctness 
  of 
  the 
  interpretation 
  advanced 
  in 
  our 
  preliminary 
  

   communications 
  last 
  year. 
  Professor 
  Gregoire 
  has 
  consider- 
  

   ably 
  altered 
  the 
  views 
  previously 
  expressed 
  Jby 
  hiuiself 
  as 
  to 
  

   the 
  actual 
  sequence 
  of 
  events 
  during 
  the 
  miroses 
  in 
  question, 
  

   and 
  he 
  cites 
  in 
  support 
  of 
  his 
  present 
  position 
  some 
  as 
  yet 
  

   unpublished 
  work 
  of 
  his 
  pupil 
  M. 
  Bergh. 
  We 
  think 
  it 
  

   desirable 
  to 
  examine 
  the 
  evidence 
  for 
  the 
  views 
  he 
  now 
  seems 
  

   to 
  hold 
  in 
  so 
  far 
  as 
  they 
  are 
  set 
  forth 
  in 
  his 
  last 
  paper. 
  

  

  He 
  divides 
  the 
  prophase 
  stage 
  of 
  the 
  heterotype 
  mitosis 
  

   into 
  two 
  phases, 
  the 
  first 
  extending 
  from 
  the 
  commencement 
  

   of 
  the 
  process 
  and 
  terminating 
  with 
  the 
  formation 
  of 
  the 
  thick 
  

   spireme 
  (spireme 
  epais), 
  the 
  second 
  beginning 
  with 
  this 
  

   phase 
  and 
  culminating 
  in 
  the 
  formation 
  of 
  the 
  definitive 
  

   chromosomes. 
  After 
  the 
  first 
  differentiation 
  of 
  the 
  chromatic 
  

   filaments 
  by 
  the 
  breaking 
  down 
  of 
  the 
  alveolar 
  arrangement 
  

   which 
  previously 
  was 
  associated 
  with 
  the 
  distribution 
  of 
  the 
  

   chromatin 
  in 
  a 
  reticular-like 
  way 
  throughout 
  the 
  nucleus, 
  the 
  

   synaptic 
  contraction 
  sets 
  in. 
  Most 
  of 
  the 
  filaments 
  are 
  indis- 
  

   tinguishable, 
  but 
  those 
  that 
  can 
  be 
  identified 
  are 
  thin. 
  In 
  

   several 
  places 
  filaments 
  may 
  be 
  seen 
  to 
  run 
  pai'allel, 
  some- 
  

   times 
  twisted 
  (entrelacees) 
  and 
  finally 
  the 
  two 
  thin 
  threads 
  

   fuse 
  to 
  form 
  a 
  thick 
  one. 
  Following 
  on 
  this 
  is 
  seen 
  a 
  thick 
  

   continuous 
  spireme 
  thread 
  which 
  disengages 
  itself 
  from 
  the 
  

   synaptic 
  contraction 
  and 
  spreads 
  through 
  the 
  nucleus. 
  Soon 
  

   a 
  " 
  longitudinal 
  fission 
  " 
  appears 
  in 
  the 
  thread, 
  but 
  he 
  con- 
  

  

  1 
  V. 
  Gregoire, 
  " 
  La 
  Reductiou 
  numerique 
  des 
  Chromosomes 
  et 
  li§g 
  Cineses 
  

   de 
  Maturation," 
  ' 
  La 
  Cellule,' 
  t. 
  xxi. 
  

  

  