﻿402 
  JOHN 
  RENNIE. 
  

  

  them 
  to 
  be 
  fuiictionless 
  effete 
  portions 
  of 
  tlie 
  pancreas, 
  or 
  

   embryonic 
  remains. 
  Others, 
  again, 
  regard 
  them 
  as 
  contri- 
  

   buting 
  to 
  the 
  production 
  of 
  the 
  pancreas 
  secretion, 
  e. 
  g. 
  

   Giannelli 
  ed 
  Giacomini 
  (4) 
  and 
  Jarotsky, 
  already 
  quoted. 
  

  

  The 
  facts 
  as 
  far 
  as 
  observed 
  by 
  me 
  seem 
  to 
  point 
  clearly 
  to 
  

   an 
  internal 
  secretory 
  function. 
  These 
  bodies 
  are 
  ductless 
  

   glands; 
  they 
  are 
  all 
  well 
  supplied 
  with 
  capillaries, 
  and 
  in 
  

   some 
  cases 
  these 
  are 
  very 
  abundant. 
  In 
  some, 
  structures 
  for 
  

   regulating 
  the 
  flow 
  of 
  blood 
  through 
  their 
  tissues 
  are 
  present; 
  

   and 
  this, 
  taken 
  in 
  conjunction 
  Avith 
  the 
  different 
  appearances 
  

   met 
  with 
  in 
  the 
  cytoplasm 
  and 
  nuclei, 
  leaves 
  little 
  doubt 
  but 
  

   that 
  they 
  are 
  active 
  organs. 
  Whether 
  two 
  types 
  of 
  cell 
  

   exist 
  in 
  certain 
  instances 
  or 
  not, 
  the 
  irregularly 
  polyhedral 
  

   lightly 
  staining 
  forms 
  occnr 
  in 
  all. 
  Reviewing 
  these, 
  it 
  is 
  

   noted 
  that 
  the 
  nuclei 
  occurred 
  with 
  regularly 
  spherical 
  or 
  

   oval 
  outline, 
  and 
  also 
  very 
  irregular 
  in 
  form. 
  In 
  the 
  latter 
  

   the 
  chromatin 
  was 
  not 
  so 
  abundant 
  ; 
  the 
  cytoplasm, 
  too, 
  was 
  

   more 
  open 
  and 
  less 
  granular. 
  Such 
  like 
  differences 
  Ditimare 
  

   also 
  noted 
  and 
  correctly, 
  I 
  think, 
  inteipreted 
  as 
  indications 
  of 
  

   different 
  functional 
  states. 
  They 
  correspond, 
  according 
  to 
  

   Baum 
  {' 
  Deutsch. 
  Zeitschr. 
  f. 
  Thiermed. 
  u. 
  vergl. 
  Pathol.' 
  

   xii, 
  1886), 
  with 
  resting 
  and 
  active 
  conditions 
  respectively 
  of 
  

   gland-cells. 
  

  

  In 
  a 
  future 
  paper 
  I 
  hope 
  to 
  give 
  an 
  account 
  of 
  certain 
  

   experiments 
  with 
  extracts 
  of 
  these 
  " 
  islets," 
  the 
  results 
  of 
  

   which, 
  as 
  far 
  as 
  at 
  present 
  obtained, 
  appear 
  to 
  indicate 
  the 
  

   presence 
  in 
  them 
  of 
  substances 
  possessing 
  some 
  physiological 
  

   activity. 
  

  

  Conclusions. 
  

  

  The 
  occurrence 
  of 
  epithelial 
  islets 
  of 
  the 
  pancreas 
  is 
  wide- 
  

   spread 
  in 
  Teleostei. 
  

  

  In 
  many 
  of 
  these 
  there 
  is 
  an 
  encapsuled 
  islet 
  (" 
  principal 
  

   islet 
  "), 
  of 
  relatively 
  large 
  size 
  and 
  of 
  constant 
  occurrence, 
  

   whose 
  relation 
  to 
  the 
  pancreatic 
  tissue 
  is 
  frequently 
  extremely 
  

   slight. 
  In 
  some 
  species 
  it 
  was 
  the 
  only 
  body 
  of 
  this 
  nature 
  

   found. 
  

  

  