﻿MATUKATION, 
  ETC., 
  OF 
  THE 
  EGG 
  OF 
  THE 
  AXOLOTL. 
  471 
  

  

  and, 
  when 
  they 
  apply 
  the 
  theory 
  to 
  the 
  explanation 
  of 
  cell- 
  

   division, 
  the 
  very 
  obvious 
  fact 
  that 
  in 
  many 
  cases 
  these 
  

   " 
  elastic 
  " 
  threads 
  never 
  reach 
  the 
  surface 
  of 
  the 
  cell 
  at 
  all. 
  

  

  Neither 
  can 
  I 
  agree 
  that 
  the 
  centrosome 
  is 
  passive, 
  the 
  mere 
  

   " 
  Insertionsmittelpunkt 
  " 
  of 
  contractile 
  fibrillas. 
  In 
  spite 
  of 
  

   the 
  asserted 
  absence 
  of 
  the 
  centrosome 
  in 
  the 
  higher 
  plants 
  — 
  

   and 
  we 
  shall 
  do 
  well 
  to 
  remember 
  that 
  the 
  question 
  is 
  still 
  

   sub 
  judice 
  and 
  that 
  much 
  depends 
  on 
  our 
  definition 
  of 
  a 
  

   centrosome 
  — 
  and 
  in 
  spite 
  of 
  the 
  difficulties 
  presented 
  by 
  the 
  

   facts 
  of 
  multi-polar 
  mitosis, 
  I 
  confess 
  I 
  am 
  one 
  of 
  those 
  who 
  

   believe 
  in 
  the 
  centrosome 
  as 
  active 
  — 
  whether 
  permanent 
  or 
  

   not 
  is 
  of 
  little 
  moment 
  — 
  and 
  as 
  active 
  because 
  it 
  is 
  hygro- 
  

   scopic. 
  This 
  conception 
  of 
  the 
  centrosome 
  as 
  an 
  absorbent 
  

   of 
  the 
  water 
  of 
  the 
  cell 
  is 
  of 
  course 
  not 
  new. 
  BUtschli 
  (1894) 
  

   suggested 
  that 
  it 
  had 
  this 
  function 
  and 
  showed 
  that 
  in 
  his 
  

   artificial 
  foams 
  a 
  radial 
  structure 
  might 
  be 
  induced 
  round 
  a 
  

   central 
  hygroscopic 
  particle. 
  But 
  here 
  our 
  paths 
  diverge. 
  

   For 
  Biitschli 
  an 
  alveolar 
  structure 
  is 
  appropriate 
  to 
  all 
  

   living 
  substance 
  and 
  the 
  aster 
  we 
  see 
  is 
  but 
  the 
  radial 
  

   rearrangement 
  of 
  the 
  alveoli 
  that 
  existed 
  before. 
  The 
  

   theory 
  has 
  grave 
  objections. 
  In 
  the 
  first 
  place 
  an 
  assump- 
  

   tion 
  is 
  made 
  as 
  to 
  the 
  structure 
  of 
  protoplasm, 
  an 
  assumption 
  

   which 
  has 
  not 
  yet 
  been 
  vindicated; 
  and 
  in 
  the 
  second 
  no 
  

   explanation 
  is 
  offered 
  of 
  the 
  manner 
  in 
  which 
  an 
  aster 
  so 
  

   produced 
  could 
  perform 
  its 
  functions. 
  

  

  On 
  the 
  other 
  hand 
  while 
  the 
  theory 
  which 
  I 
  have 
  ventured 
  

   to 
  put 
  forward 
  asks 
  for 
  no 
  other 
  preconception 
  of 
  the 
  nature 
  

   of 
  living 
  substance 
  than 
  that 
  it 
  is 
  a 
  colloidal 
  fluid, 
  it 
  does, 
  I 
  

   hope, 
  indicate 
  a 
  way 
  in 
  which 
  those 
  structures 
  which 
  we 
  do 
  

   really 
  see 
  may 
  not 
  only 
  be 
  foi-med, 
  but 
  also 
  be 
  capable 
  of 
  

   effecting 
  the 
  observed 
  results, 
  as 
  far 
  at 
  least 
  as 
  the 
  division 
  

   of 
  the 
  nucleus 
  goes. 
  (The 
  division 
  of 
  the 
  centrosome 
  is 
  

   another 
  matter 
  entirely.) 
  This 
  way 
  is 
  by 
  the 
  redistribution 
  

   of 
  the 
  watery 
  contents 
  of 
  the 
  cell, 
  and 
  should 
  this 
  lead 
  to 
  a 
  

   disturbance 
  of 
  the 
  equilibrium 
  of 
  internal 
  surface-tensions 
  a 
  

   way 
  may 
  be 
  opened 
  for 
  the 
  explanation 
  of 
  cell-division 
  as 
  

   well. 
  The 
  facts 
  of 
  normal 
  fertilisation 
  might 
  thus 
  be 
  brought 
  

  

  VOL. 
  48, 
  FAUT 
  3. 
  NEW 
  SERIES. 
  34 
  

  

  