﻿Eeproductive 
  organs 
  of 
  Taenia 
  pisiformis. 
  375 
  

  

  due 
  to 
  mutual 
  pressure, 
  the 
  cells 
  having 
  separated 
  slightly 
  in 
  

   fixation? 
  Were 
  this 
  so 
  we 
  ought 
  to 
  find 
  the 
  same 
  sharp 
  lines 
  of 
  

   separation 
  between 
  cells 
  e 
  and 
  f 
  Fig. 
  40 
  as 
  between 
  ah 
  and 
  cd. 
  

   But 
  such 
  is 
  not 
  the 
  case. 
  Furthermore, 
  such 
  an 
  objection 
  could 
  

   scarcely 
  be 
  applied 
  to 
  Fig. 
  38 
  as 
  I 
  have 
  already 
  stated. 
  There 
  is 
  

   thus 
  presented 
  here 
  I 
  believe 
  a 
  complete 
  series 
  of 
  stages 
  in 
  amitosis 
  

   from 
  Figs. 
  35 
  and 
  37 
  to 
  38 
  and 
  40, 
  and 
  Richaeds 
  objection 
  that 
  

   ". 
  . 
  . 
  such 
  a 
  complete 
  series 
  is 
  extremely 
  difficult 
  to 
  establish 
  in 
  the 
  

   cestodes; 
  its 
  assumption, 
  therefore,... 
  is 
  ultra 
  radical'' 
  (1. 
  c, 
  p. 
  125), 
  

   is, 
  in 
  these 
  cases 
  at 
  least, 
  diminished 
  if 
  not 
  removed. 
  

  

  But 
  if, 
  as 
  already 
  stated, 
  positive 
  evidence 
  of 
  amitosis 
  (of 
  both 
  

   nucleus 
  and 
  cytoplasm) 
  is 
  not 
  frequent 
  ^) 
  and 
  no 
  evidence 
  of 
  mitosis 
  

   is 
  present, 
  how 
  is 
  cell 
  increase 
  in 
  the 
  early 
  testis 
  to 
  be 
  explained? 
  

   I 
  believe 
  that 
  new 
  nuclei 
  arise 
  either 
  from 
  chromidial 
  extrusions 
  

   from 
  old 
  nuclei, 
  or 
  de 
  novo 
  in 
  the 
  cytoplasm 
  of 
  the 
  spermatogonia. 
  

   A 
  very 
  probable 
  case 
  of 
  the 
  former 
  is 
  shown 
  in 
  Fig. 
  36 
  which 
  shows 
  

   a 
  chromatin 
  granule 
  just 
  passing, 
  as 
  I 
  believe, 
  from 
  the 
  nucleus 
  

   into 
  the 
  cytoplasm. 
  The 
  structure 
  of 
  the 
  nucleus 
  — 
  a 
  loose 
  collection 
  

   of 
  chromatin 
  bodies 
  without 
  a 
  membrane 
  ^) 
  — 
  renders 
  the 
  extrusion 
  

   of 
  chromidia 
  an 
  easy 
  matter. 
  After 
  their 
  extrusion 
  new 
  chromatin 
  is 
  

   added 
  and 
  that 
  part 
  of 
  the 
  cell 
  containing 
  them 
  is 
  constricted 
  off, 
  to 
  give 
  

   rise 
  in 
  its 
  turn 
  to 
  other 
  cells. 
  I 
  have 
  seen 
  several 
  cases 
  of 
  spermato- 
  

   gonia 
  undergoing 
  this 
  process 
  of 
  multiplication, 
  and 
  consider 
  it 
  an 
  

   important 
  method 
  of 
  cellular 
  increase. 
  It 
  is 
  obviously 
  impossible 
  to 
  

   say 
  however 
  whether 
  any 
  chromatin 
  granule 
  in 
  the 
  cytoplasm 
  is 
  a 
  

   chromidial 
  extrusion 
  or 
  a 
  de 
  novo 
  formation. 
  The 
  absence 
  of 
  anuc- 
  

   leate 
  cells 
  and 
  of 
  cells 
  containing 
  only 
  one 
  small 
  chromatin 
  body 
  

   argues 
  against 
  the 
  latter 
  mode 
  of 
  nuclear 
  development 
  in 
  the 
  testis^ 
  

   The 
  method 
  of 
  chromatin 
  increase 
  in 
  the 
  newly 
  formed 
  cells 
  I 
  have 
  

   been 
  unable 
  to 
  determine. 
  Whether 
  the 
  chromidial 
  anlagen 
  of 
  the 
  new 
  

   nuclei 
  give 
  rise 
  by 
  division 
  to 
  more 
  chromatin 
  bodies, 
  or 
  whether 
  

   these 
  latter 
  are 
  formed 
  from 
  the 
  cytoplasm 
  under 
  the 
  influence 
  of 
  

   the 
  former 
  is 
  impossible 
  to 
  say. 
  

  

  The 
  testes 
  are 
  surrounded 
  from 
  the 
  outset 
  by 
  the 
  parent 
  paren-. 
  

   chyma 
  cell, 
  the 
  relation 
  being 
  similar 
  to 
  that 
  of 
  chalk 
  cell 
  and, 
  

  

  1) 
  In 
  some 
  2500 
  nuclei 
  counted 
  11 
  probable 
  and 
  68 
  doubtful 
  amitoses 
  

   were 
  observed. 
  

  

  2) 
  In 
  many 
  slides 
  the 
  early 
  spermatogonia 
  show 
  apparently 
  definite 
  

   membranes, 
  but 
  even 
  here 
  careful 
  examination 
  fails 
  to 
  establish 
  their 
  com- 
  

   pleteness 
  in 
  many 
  cases. 
  

  

  25* 
  

  

  