﻿EPITHELIAL 
  ISLETS 
  OF 
  THE 
  PANCREAS 
  IN 
  TELEOSTEI. 
  403 
  

  

  The 
  smaller 
  islets, 
  which 
  do 
  not 
  appear 
  to 
  be 
  constant 
  in 
  

   number 
  (Lophius), 
  it 
  is 
  suggested, 
  probably 
  originated 
  as 
  

   ''accessory 
  bodies/' 
  but 
  are 
  now 
  established 
  as 
  definite 
  organs. 
  

  

  These 
  islets 
  are 
  blood-glands 
  which 
  have 
  entered 
  into 
  a 
  

   secondary 
  relation 
  with 
  the 
  pancreas. 
  This 
  has 
  been 
  brought 
  

   about 
  in 
  Teleostei 
  mainly 
  by 
  the 
  tendency 
  of 
  the 
  diffuse 
  

   pancreas 
  to 
  envelop 
  or 
  invade 
  other 
  tissues. 
  In 
  the 
  case 
  of 
  

   these 
  so-called 
  islets 
  in 
  the 
  compact 
  pancreas 
  of 
  Teleostei, 
  and 
  

   also 
  of 
  higher 
  animals, 
  the 
  closer 
  relation 
  is 
  due 
  to 
  the 
  common 
  

   embryonic 
  origin 
  of 
  the 
  two 
  tissues. 
  Here 
  the 
  islets 
  form 
  a 
  

   constituent 
  part 
  of 
  the 
  pancreas, 
  although 
  they 
  maintain 
  

   their 
  function 
  as 
  an 
  internal 
  secretory 
  gland. 
  The 
  primitive 
  

   condition, 
  however, 
  is 
  that 
  seen 
  in 
  Teleostei 
  with 
  diffuse 
  

   pancreas, 
  wliere 
  the 
  islets 
  are 
  both 
  morphologically 
  and 
  

   functionally 
  distinct. 
  

  

  No 
  evidence 
  of 
  transitional 
  forms 
  to 
  support 
  the 
  view 
  that 
  

   the 
  islets 
  undergo 
  metamorphosis 
  into 
  zymogenous 
  tissue 
  was 
  

   found. 
  The 
  reputed 
  changes 
  of 
  zymogenous 
  elements 
  to 
  islet 
  

   tissue 
  are 
  possibly 
  degenerative, 
  or 
  regressive 
  to 
  the 
  " 
  cellular 
  

   process 
  " 
  condition 
  of 
  the 
  embryo. 
  

  

  From 
  internal 
  histological 
  evidence, 
  these 
  bodies 
  are 
  pro- 
  

   bably 
  functionally 
  active. 
  (Confirmatory 
  of 
  Diamare's 
  work.) 
  

  

  References. 
  

  

  1. 
  Cole 
  and 
  Johnstone. 
  — 
  "Pleuronectes," 
  'L.M.B.C. 
  Memoirs,' 
  1901. 
  

  

  2. 
  DoGiEL, 
  A. 
  S. 
  — 
  " 
  Zur 
  frage 
  iiber 
  die 
  Ausliirgange 
  des 
  Pankreas 
  des 
  

  

  Menscben," 
  'Arch. 
  f. 
  Anat. 
  u. 
  Plijs./ 
  Aiiat. 
  Abt. 
  Jalirg., 
  s. 
  117—122, 
  

   1S93. 
  

  

  3. 
  DiAMAEE, 
  V. 
  — 
  " 
  Studii 
  comparativi 
  sulle 
  isole 
  di 
  Langerhans 
  de 
  

  

  pancreas," 
  'Intern. 
  Monatssclir. 
  f. 
  Anat. 
  u. 
  Piiys.,' 
  Bd. 
  xvi, 
  pp. 
  155 
  — 
  209. 
  

  

  4. 
  GiANNELLi 
  ED 
  GiACOMiNi. 
  — 
  " 
  Riclierclic 
  istologicbe 
  sub 
  tubo 
  digerente 
  

  

  del 
  Rettili," 
  'II. 
  Accad. 
  d. 
  Fisiocrit. 
  in 
  Siena,' 
  1S96. 
  

  

  5. 
  Hakkis 
  and 
  Gow. 
  — 
  "Note 
  upon 
  one 
  or 
  two 
  Points 
  on 
  the 
  Comparative 
  

  

  Histology 
  of 
  the 
  Pancreas," 
  'Journ. 
  of 
  Anat. 
  and 
  Piiys.,' 
  vol. 
  xv, 
  

   pp. 
  349—360. 
  

  

  6. 
  Jakotsky, 
  a. 
  J. 
  — 
  tJber 
  die 
  A'eranderungen 
  in 
  der 
  grosse 
  und 
  im 
  Bau 
  der 
  

  

  Pankreaszeilen 
  bei 
  einigen 
  Artcn 
  der 
  Inanition," 
  'Arch. 
  f. 
  patli. 
  Anat. 
  

   u. 
  Pliys.,' 
  Bd. 
  clvi, 
  Hefi 
  3, 
  s. 
  409—450, 
  1899. 
  

  

  