﻿Studies 
  on 
  Synapsis. 
  

  

  319 
  

  

  hematoxylin, 
  but 
  translucent 
  and 
  less 
  chromatic 
  than 
  the 
  reticulum 
  at 
  all 
  

   stages 
  after 
  treatment 
  with 
  heemalum. 
  In 
  all 
  these 
  cases 
  the 
  early 
  nucleolar 
  

   particles 
  were 
  deeply 
  stained 
  by 
  the 
  dye. 
  With 
  methylene 
  blue-eosin 
  

   staining 
  the 
  plasmosome 
  and 
  nucleolar 
  particles 
  and 
  gemmules 
  were 
  

   basophil, 
  and 
  indistinguishable 
  from 
  the 
  reticulum 
  after 
  acid 
  fixation, 
  but 
  

   acidophil 
  and 
  sharply 
  differentiated 
  from 
  the 
  network 
  after 
  fixation 
  by 
  

   Gatenby's 
  method. 
  Auerbach's 
  fuchsin 
  methyl 
  green 
  after 
  sublimate 
  

   acetic 
  treatment 
  gave 
  a 
  definite 
  differentiation 
  ; 
  but 
  after 
  acid-free 
  fixation 
  

   acidified 
  Ehrlich 
  Biondi's 
  methyl 
  green-fuchsin-orange 
  G 
  failed 
  to 
  give 
  the 
  

   characteristic 
  chromatin 
  reaction. 
  

  

  2. 
  Spermatogenesis 
  in 
  P. 
  americana. 
  

   The 
  spermatogenesis 
  of 
  the 
  Blattidse 
  has 
  been 
  dealt 
  with 
  from 
  various 
  

   aspects 
  by 
  la 
  Valette 
  St. 
  George, 
  Von 
  Bath, 
  Erlanger, 
  Stevens 
  and 
  Wassilieff 
  ; 
  

   but 
  as 
  none 
  of 
  these 
  writers 
  have 
  been 
  primarily 
  concerned 
  with 
  matter 
  under 
  

   consideration 
  — 
  the 
  problem 
  of 
  synapsis 
  — 
  it 
  is 
  hardly 
  necessary 
  to 
  include 
  

   further 
  reference 
  to 
  their 
  work. 
  Farmer 
  and 
  Moore, 
  '05, 
  and 
  Morse, 
  '09, 
  on 
  the 
  

   other 
  hand 
  devoted 
  their 
  attention 
  principally 
  to 
  a 
  description 
  of 
  the 
  reductive 
  

   processes 
  ; 
  and 
  as 
  will 
  be 
  seen 
  later, 
  their 
  conclusions 
  are 
  signally 
  lacking 
  in 
  

   conformity 
  on 
  most 
  points 
  of 
  crucial 
  interest. 
  Neither 
  of 
  these 
  investigators 
  

   paid 
  any 
  attention 
  to 
  the 
  oogenesis 
  of 
  the 
  same 
  species, 
  though 
  as 
  already 
  shown 
  

   the 
  early 
  events 
  of 
  the 
  meiotic 
  phase 
  can 
  be 
  there 
  witnessed 
  with 
  remarkable 
  

   clarity 
  and 
  precision. 
  Owing 
  partly 
  to 
  the 
  greater 
  width 
  and 
  adiposity 
  of 
  the 
  

   testes 
  as 
  compared 
  with 
  the 
  minute 
  ovarioles 
  of 
  the 
  larvae, 
  it 
  is 
  difficult 
  in 
  

   the 
  former 
  case 
  to 
  ensure 
  a 
  sufficiently 
  rapid 
  penetration 
  to 
  preserve 
  the 
  

   contraction 
  stages 
  in 
  good 
  condition, 
  and 
  even 
  with 
  smear 
  preparations 
  which 
  

   are 
  subject 
  to 
  instantaneous 
  fixation 
  the 
  constitution 
  of 
  the 
  bouquet 
  presents 
  

   a 
  very 
  much 
  more 
  difficult 
  problem 
  in 
  the 
  male 
  sex 
  cells 
  than 
  in 
  those 
  of 
  the 
  

   alternate 
  sex. 
  Nevertheless 
  there 
  remain 
  certain 
  points 
  for 
  the 
  elucidation 
  of 
  

   which 
  the 
  spermatogenesis 
  offers 
  more 
  favourable 
  material 
  for 
  study 
  than 
  

   oogenesis. 
  By 
  securing 
  a 
  supply 
  of 
  testes 
  from 
  individuals 
  that 
  have 
  not 
  

   attained 
  to 
  sexual 
  maturity 
  it 
  is 
  possible 
  to 
  obtain 
  plentiful 
  sections 
  from 
  

   cysts 
  exhibiting 
  every 
  stage 
  between 
  the 
  anaphase 
  and 
  the 
  formation 
  of 
  the 
  

   spermatogonial 
  reticulum. 
  Later 
  instars 
  likewise 
  provide 
  a 
  greater 
  propor- 
  

   tions 
  of 
  cysts 
  with 
  heterotypic 
  prophases 
  and 
  metaphases 
  than 
  will 
  be 
  found 
  

   to 
  occur 
  in 
  the 
  testes 
  of 
  the 
  adult. 
  Special 
  attention 
  will 
  therefore 
  be 
  paid 
  

   in 
  this 
  section 
  to 
  : 
  {a) 
  the 
  character 
  of 
  the 
  premeiotic 
  telophase 
  in 
  its 
  bearing 
  

   on 
  the 
  heterotypic 
  prophase 
  ; 
  and 
  (b) 
  the 
  means 
  by 
  which 
  the 
  diplotene 
  loops 
  

   are 
  transformed 
  into 
  the 
  mature 
  spindle 
  bivalents. 
  

  

  