﻿468 
  J. 
  W. 
  .TLINKINSON. 
  

  

  phosphoric 
  acid, 
  a 
  characteristic 
  constituent 
  of 
  the 
  nucleins 
  

   (Mann) 
  has 
  ah-eacly 
  been 
  mentioned 
  as 
  one 
  of 
  the 
  reagents 
  

   used 
  in 
  the 
  production 
  of 
  the 
  artificial 
  asters 
  ; 
  and 
  Berg 
  has 
  

   shown 
  that 
  the 
  precipitation 
  granules 
  produced 
  by 
  the 
  action 
  

   of 
  nucleic 
  acid 
  and 
  nuclein 
  on 
  clupein, 
  a 
  protamin, 
  are 
  

   capable 
  of 
  swelling 
  up 
  with 
  tlie 
  water 
  they 
  absorb. 
  Further, 
  

   since, 
  as 
  is 
  well 
  known, 
  nucleic 
  acid 
  and 
  nuclein 
  precipitate 
  

   albumins— 
  in 
  virtue 
  apparently 
  of 
  this 
  same 
  metaphosphoric 
  

   acid 
  — 
  we 
  shall, 
  on 
  the 
  hypothesis 
  I 
  am 
  advocating, 
  have 
  to 
  

   regard 
  the 
  spindle-fibres 
  as 
  solid 
  or 
  at 
  least 
  as 
  solid 
  as 
  these 
  

   proteid 
  precipitates 
  usually 
  are. 
  That 
  the 
  spindle 
  has 
  a 
  con- 
  

   siderable 
  amount 
  of 
  rigidity 
  seems 
  to 
  be 
  shown 
  by 
  the 
  fact 
  

   observed 
  by 
  Gardiner 
  and 
  Vejdovsky 
  that 
  it 
  does 
  not 
  readily 
  

   change 
  its 
  shape 
  even 
  when 
  the 
  egg 
  is 
  deformed 
  or 
  burst. 
  

  

  The 
  spindle-fibres 
  are 
  then 
  primarily 
  lamellas 
  lying 
  between 
  

   radial 
  tubes 
  running 
  out 
  from 
  the 
  centrosome 
  and 
  consisting 
  

   of 
  a 
  precipitate 
  of 
  the 
  albumins 
  of 
  the 
  cell 
  (or 
  nucleus) 
  by 
  the 
  

   nucleins 
  in 
  solution 
  in 
  the 
  tubes; 
  by 
  the 
  anastomosis 
  of 
  

   adjacent 
  outgrowths 
  the 
  lamellas 
  may 
  become 
  converted 
  into 
  

   actual 
  fibres 
  ; 
  while 
  the 
  concentric 
  zones 
  of 
  the 
  real 
  asters 
  

   are 
  produced, 
  as 
  they 
  are 
  in 
  the 
  artificial, 
  by 
  the 
  branching 
  

   of 
  the 
  outgrowths 
  at 
  points 
  equidistant 
  from 
  the 
  centre. 
  

   Where 
  two 
  such 
  radial 
  systems 
  meet 
  a 
  spindle 
  is 
  formed, 
  the 
  

   chromosomes 
  being 
  pushed 
  into 
  the 
  equator 
  ; 
  if 
  the 
  opposed 
  

   ends 
  of 
  the 
  radial 
  tubes 
  fuse 
  bi-polar 
  fibres 
  will 
  result, 
  if 
  they 
  

   inter-digitate, 
  fibres 
  intercrossing 
  at 
  the 
  equator, 
  if 
  they 
  meet 
  

   but 
  do 
  not 
  fuse, 
  an 
  achromatic 
  equatorial 
  plate. 
  This 
  condition 
  

   may 
  be 
  easily 
  imitated 
  (Fig. 
  D.). 
  In 
  the 
  anaphase 
  of 
  the 
  

   fertilisation 
  spindle 
  of 
  the 
  Axolotl 
  I 
  have 
  described 
  such 
  a 
  

   iDlate 
  ; 
  but 
  there 
  is 
  an 
  earlier 
  stage 
  in 
  Avhicli 
  the 
  fibres 
  pass 
  

   continuously 
  from 
  pole 
  to 
  pole. 
  I 
  think 
  this 
  may 
  be 
  explained 
  

   as 
  follows 
  : 
  I 
  have 
  often 
  observed 
  that 
  the 
  outer 
  end 
  of 
  the 
  

   artificial 
  tubes 
  are 
  covered 
  only 
  by 
  au 
  extremely 
  thin 
  mem- 
  

   brane, 
  apparently 
  because 
  the 
  concentration 
  of 
  the 
  liquid 
  inside 
  

   is 
  too 
  low 
  to 
  produce 
  a 
  copious 
  precipitate. 
  Such 
  thin-walled 
  

   ends 
  would 
  readily 
  fuse, 
  but 
  as 
  the 
  concentration 
  increased 
  at 
  

   this 
  point 
  the 
  dissolved 
  proteids 
  would 
  be 
  reprecipitated. 
  

  

  