﻿470 
  J. 
  W. 
  JENKINSON. 
  

  

  ill 
  the 
  cytoplasm 
  in 
  exactly 
  tlie 
  same 
  way 
  as, 
  for 
  example, 
  

   the 
  ammonium 
  sulphate 
  aster 
  is 
  resoluble 
  in 
  an 
  excess 
  of 
  

   the 
  surrounding 
  albumen. 
  

  

  My 
  theory 
  then 
  of 
  the 
  formation 
  of 
  these 
  structures 
  which 
  

   appear 
  in 
  the 
  egg 
  during 
  fertilisation 
  is 
  that 
  they 
  are 
  

   produced 
  under 
  the 
  influence 
  of 
  the 
  middle-piece 
  and 
  centro- 
  

   some 
  in 
  virtue 
  of 
  a 
  capacity 
  which 
  these 
  bodies 
  possess 
  of 
  

   withdrawing 
  water 
  from 
  the 
  cytoplasm/ 
  of 
  swelling 
  up 
  and 
  

   dissolving 
  in 
  the 
  water 
  so 
  absorbed, 
  and 
  then 
  giving 
  off 
  

   radial 
  outgrowths 
  which 
  precipitate 
  the 
  proteids 
  of 
  the 
  cell 
  

   so 
  producing 
  an 
  aster 
  and, 
  by 
  the 
  combined 
  elfect 
  of 
  two, 
  

   the 
  fertilisation 
  spindle. 
  

  

  I 
  am 
  therefore 
  very 
  closely 
  in 
  accord 
  with 
  those 
  authors 
  

   who 
  like 
  Moves 
  (1896, 
  1898) 
  see 
  in 
  such 
  facts 
  as 
  the 
  invagina- 
  

   tion 
  of 
  the 
  nuclear 
  membrane, 
  the 
  divergence 
  of 
  the 
  centro- 
  

   somes 
  and 
  the 
  broadening 
  of 
  the 
  spindle, 
  strong 
  grounds 
  for 
  

   holding 
  that 
  spindle-fibres 
  and 
  astral 
  rays 
  are 
  structures 
  

   which 
  grow 
  out 
  from 
  the 
  centrosome. 
  The 
  difference 
  between 
  

   us 
  is 
  that 
  according 
  to 
  my 
  theory 
  it 
  is 
  not 
  the 
  fibres, 
  but 
  the 
  

   inter-fibrillar 
  spaces 
  or 
  alveoli 
  which 
  ai-e 
  the 
  more 
  actively 
  

   concerned 
  in 
  the 
  process. 
  Not 
  that 
  I 
  regard 
  all 
  asters 
  as 
  

   necessarily 
  formed 
  in 
  this 
  way. 
  It 
  is 
  quite 
  probable 
  that 
  in 
  

   many 
  cases 
  asters 
  may 
  be 
  precipitated 
  by 
  the 
  centrosome 
  in 
  

   the 
  manner 
  termed 
  " 
  Selbststrahlung 
  " 
  by 
  Fischer. 
  Most 
  

   authors 
  of 
  course 
  figure 
  asters 
  of 
  this 
  type, 
  that 
  is, 
  systems 
  

   of 
  radiating 
  disconnected 
  straight 
  lines. 
  

  

  On 
  the 
  other 
  hand 
  I 
  stand 
  in 
  absolute 
  opposition 
  to 
  those 
  

   who 
  regard 
  rays 
  and 
  fibres 
  as 
  permanent 
  organs 
  of 
  the 
  cell, 
  

   and 
  whose 
  whole 
  cytological 
  philosophy 
  is 
  summed 
  up 
  in 
  the 
  

   dogma 
  " 
  Omnis 
  radius 
  e 
  radio." 
  Such 
  theories 
  ignore 
  the 
  

   periodic 
  disappearance 
  and 
  re-formation 
  of 
  these 
  structures, 
  

  

  ' 
  Dr. 
  llamsdeu 
  has 
  suggested 
  to 
  me 
  that 
  tlie 
  centrosome 
  may 
  not 
  only 
  be 
  

   hygroscopic, 
  but 
  may 
  either 
  itself 
  undergo 
  decomposiiion 
  or 
  possess 
  a 
  ferment 
  

   which 
  would 
  produce 
  such 
  an 
  effect 
  on 
  the 
  cytoplasm. 
  In 
  either 
  case 
  tlie 
  

   result 
  would 
  be 
  an 
  increase 
  in 
  the 
  number 
  of 
  molecules, 
  that 
  is, 
  in 
  the 
  osmotic 
  

   pressure. 
  Tiiis 
  might 
  be 
  partly 
  responsible 
  for 
  the 
  formation 
  of 
  the 
  aster 
  (see 
  

   above). 
  

  

  