﻿410 
  J. 
  W. 
  JENKINSON. 
  

  

  on 
  the 
  validity 
  of 
  our 
  conceptions 
  of 
  cell 
  structure 
  and 
  

   phenomena. 
  

  

  Fischer 
  has 
  shown 
  that 
  a 
  structure 
  can 
  be 
  given 
  to 
  solu- 
  

   tions 
  of 
  proteids 
  by 
  precipitation 
  with 
  the 
  ordinary 
  fixing 
  

   reagents, 
  the 
  structure 
  being 
  either 
  granular 
  or 
  reticular, 
  and 
  

   from 
  this 
  he 
  argues 
  that 
  much, 
  if 
  not 
  all, 
  of 
  the 
  structure 
  

   observed 
  in 
  preparations 
  is 
  artifact 
  and 
  devoid 
  of 
  any 
  

   natural 
  existence 
  whatever. 
  Similar 
  views 
  were 
  expressed 
  

   about 
  the 
  same 
  time 
  by 
  Hardy. 
  

  

  Doubtless 
  there 
  is 
  much 
  force 
  in 
  the 
  criticism, 
  but 
  at 
  the 
  

   same 
  time 
  the 
  thorough-going 
  scepticism 
  which 
  Fischer 
  

   would 
  seem 
  to 
  advocate 
  is 
  surely 
  a 
  little 
  exaggerated. 
  For 
  

   in 
  the 
  first 
  place 
  such 
  structures 
  as 
  chromosomes, 
  spindle, 
  

   asters, 
  centrosome 
  have 
  all 
  been 
  observed 
  in 
  the 
  living 
  cell. 
  

   And 
  in 
  the 
  second, 
  when 
  with 
  the 
  same 
  reagent 
  we 
  find 
  

   different 
  appearances 
  in 
  successive 
  stages 
  of 
  a 
  process, 
  then 
  

   we 
  are 
  bound 
  to 
  assume 
  that 
  these 
  differences 
  are 
  at 
  least 
  the 
  

   outward 
  and 
  visible 
  signs 
  of 
  a 
  real 
  series 
  of 
  changes. 
  For 
  

   example, 
  I 
  shall 
  have 
  to 
  describe 
  in 
  the 
  sequel 
  the 
  gradual 
  

   formation 
  of 
  a 
  system 
  of 
  vacuoles 
  in 
  the 
  centre 
  of 
  the 
  sperm 
  

   sphere 
  ; 
  these 
  must 
  be 
  at 
  least 
  an 
  indication 
  of 
  the 
  local 
  

   concentration 
  of 
  some 
  watery 
  substance, 
  for 
  on 
  Fischer's 
  

   own 
  showing 
  absorption 
  of 
  water 
  precedes 
  the 
  formation 
  of 
  

   vacuoles 
  in 
  the 
  artificial 
  vacuolation 
  of 
  aleuron 
  grains 
  and 
  

   such 
  bodies 
  which 
  he 
  produces 
  by 
  means 
  of 
  reagents. 
  Nor 
  

   is 
  this 
  all. 
  If 
  the 
  different 
  structures 
  which 
  we 
  are 
  asked 
  to 
  

   regard 
  as 
  artifacts 
  form 
  a 
  regular 
  series 
  when 
  placed 
  in 
  

   chronological 
  order, 
  is 
  it 
  not 
  a 
  little 
  too 
  much 
  to 
  expect 
  us 
  

   to 
  believe 
  that 
  this 
  artificial 
  is 
  merely 
  parallel 
  with, 
  but 
  in 
  no 
  

   way 
  gives 
  us 
  a 
  true 
  representation 
  of, 
  that 
  other 
  unknown 
  

   real 
  series 
  ? 
  

  

  Without 
  then 
  going 
  so 
  far 
  as 
  to 
  assert, 
  what 
  I 
  suppose 
  no 
  

   one 
  would 
  maintain, 
  that 
  our 
  reagents 
  are 
  absolutely 
  infallible, 
  

   I 
  should 
  certainly 
  hold 
  that 
  such 
  structures 
  as 
  those 
  just 
  

   referred 
  to 
  are 
  faithfully 
  preserved 
  in 
  our 
  preparations. 
  

   Fischer 
  himself 
  admits 
  as 
  much 
  when 
  he 
  says 
  " 
  sind 
  solche 
  

   schon 
  in 
  der 
  lebenden 
  Zelle 
  zu 
  sehen 
  so 
  ist 
  es 
  zweifellos 
  dass 
  

  

  