﻿122 
  E. 
  .T. 
  ALIJ'^N. 
  

  

  appears 
  in 
  the 
  cells 
  in 
  the 
  form 
  of 
  the 
  yellowish-lorown 
  

   granules, 
  which 
  are 
  thiclcl}^ 
  congregated 
  at 
  the 
  surface 
  of 
  

   absorption. 
  The 
  nucleus 
  is 
  obviously 
  in 
  a 
  very 
  active 
  state, 
  

   and 
  its 
  position 
  at 
  the 
  base 
  of 
  the 
  cell, 
  at 
  the 
  point 
  of 
  contact 
  

   of 
  the 
  cell 
  with 
  the 
  intestinal 
  blood-sinus, 
  seems, 
  if 
  we 
  accept 
  

   the 
  view 
  advocated 
  by 
  Korschelt 
  that 
  the 
  nucleus 
  is 
  generally 
  

   to 
  be 
  found 
  where 
  the 
  chief 
  function 
  of 
  the 
  cell 
  is 
  in 
  active 
  

   progress, 
  to 
  suggest 
  that 
  the 
  food 
  substance 
  there 
  undergoes 
  

   transformation 
  and 
  is 
  passed 
  through 
  the 
  cell-wall 
  into 
  the 
  

   blood. 
  

  

  The 
  second 
  condition 
  in 
  which 
  the 
  epithelial 
  cells 
  of 
  the 
  

   intestine 
  are 
  found 
  (when 
  the 
  intestine 
  does 
  not 
  contain 
  food) 
  

   is 
  illustrated 
  in 
  fig. 
  46. 
  The 
  gland-cells 
  {(/I.), 
  which 
  in 
  the 
  

   former 
  state 
  were 
  shrivelled 
  and 
  inert, 
  are 
  now 
  large 
  and 
  

   active. 
  They 
  are 
  pear-shaped, 
  filled 
  with 
  granules 
  (which 
  in 
  

   methyl-blue-eosin 
  preparations 
  stain 
  bright 
  red), 
  and 
  their 
  

   necks 
  extend 
  quite 
  to 
  the 
  surface 
  of 
  the 
  epithelial 
  layer. 
  

   The 
  nuclei 
  are 
  clear 
  and 
  transparent, 
  with 
  deeply 
  staining 
  

   chromatin, 
  the 
  greater 
  part 
  of 
  which 
  is 
  concentrated 
  in 
  a 
  

   single 
  large 
  nucleolus. 
  

  

  The 
  columnar 
  cells 
  (ep,), 
  on 
  the 
  other 
  hand, 
  contain 
  no 
  

   granules; 
  their 
  protoplasm 
  stains 
  faintly 
  and 
  diffusely 
  (blue 
  

   in 
  methyl-blue-eosin 
  prepai-ations), 
  and 
  shows 
  only 
  an 
  indefi- 
  

   nite 
  reticulation 
  probably 
  due 
  to 
  the 
  action 
  of 
  the 
  reagents. 
  

   The 
  nuclei 
  are 
  much 
  smaller 
  than 
  in 
  the 
  active 
  epithelial 
  cells 
  

   previously 
  described 
  (cf. 
  figs. 
  45 
  and 
  40), 
  the 
  chromatin 
  

   granules 
  stain 
  less 
  deeply 
  (red), 
  and 
  the 
  whole 
  nucleus 
  is 
  

   diffusely 
  tinted 
  (blue). 
  It 
  would 
  seem, 
  therefoi-e, 
  that 
  whilst 
  

   the 
  gland-cells 
  are 
  now 
  active 
  the 
  columnar 
  cells 
  are 
  inert. 
  

  

  The 
  epithelium 
  in 
  only 
  two 
  other 
  parts 
  of 
  the 
  alimen- 
  

   tary 
  canal 
  calls 
  for 
  mention, 
  namely, 
  that 
  in 
  the 
  ventral 
  

   ciliated 
  groove 
  and 
  that 
  in 
  the 
  terminal 
  segments 
  of 
  the 
  

   body. 
  

  

  The 
  cells 
  of 
  the 
  ciliated 
  groove 
  are 
  elongated 
  and 
  distinctly 
  

   ciliated, 
  though 
  they 
  do 
  not 
  show 
  the 
  layer 
  of 
  deeply 
  staining 
  

   short 
  rods, 
  which 
  was 
  found 
  in 
  the 
  ciliated 
  cells 
  of 
  the- 
  

   oesophagus. 
  

  

  