﻿EPITHELIAL 
  ISLETS 
  OF 
  THE 
  PANCREAS 
  IN 
  TELEOSTRI, 
  399 
  

  

  the 
  extremely 
  diffuse 
  condition 
  of 
  the 
  pancreas, 
  interstitial 
  

   tissue 
  can 
  scarcely 
  be 
  said 
  to 
  exist, 
  the 
  organ 
  deriving 
  support 
  

   from 
  tlie 
  several 
  other 
  organs 
  to 
  whicli 
  it 
  is 
  adherent, 
  e. 
  g. 
  

   the 
  larger 
  blood-vessels 
  (Lophobrauclis). 
  In 
  fact, 
  just 
  in 
  

   proportion 
  as 
  tlie 
  pancreatic 
  tissue 
  has 
  a 
  more 
  or 
  less 
  massive 
  

   arrangement, 
  the 
  capsule 
  is 
  more 
  or 
  less 
  indefinite. 
  That 
  is 
  

   to 
  say, 
  the 
  capsule 
  tends 
  to 
  disappear 
  where 
  the 
  form 
  of 
  the 
  

   zymogenous 
  tissue 
  approaches 
  most 
  nearly 
  the 
  common 
  form 
  

   in 
  higher 
  animals. 
  Tliis 
  is 
  well 
  seen 
  in 
  those 
  fishes 
  where 
  the 
  

   pyloric 
  caeca 
  have 
  their 
  interspaces 
  filled 
  with 
  pancreas. 
  The 
  

   islets 
  observed 
  in 
  such 
  cases 
  had 
  no 
  capsule. 
  Where 
  they 
  

   have 
  come 
  to 
  be 
  enclosed 
  within 
  pancreatic 
  elements, 
  the 
  

   necessity 
  for 
  a 
  protecting 
  capsule 
  has 
  ceased 
  to 
  exist. 
  

  

  In 
  further 
  support 
  of 
  the 
  view 
  whicli 
  regards 
  these 
  islets 
  

   as 
  independent 
  organs, 
  two 
  other 
  points 
  appear 
  to 
  me 
  worth 
  

   stating. 
  In 
  many 
  fishes 
  the 
  peritoneal 
  membrane 
  and 
  blood- 
  

   vessels 
  are 
  pigmented, 
  and 
  in 
  such 
  cases 
  so 
  also 
  is 
  the 
  capsule 
  

   of 
  these 
  bodies, 
  although 
  I 
  have 
  never 
  seen 
  any 
  pigment 
  laid 
  

   down 
  within 
  or 
  upon 
  pancreatic 
  tissue. 
  As 
  examples 
  may 
  be 
  

   quoted 
  Pholis 
  gunnellus, 
  Zoarces 
  viviparus. 
  In 
  this 
  

   last 
  I 
  have 
  found 
  several 
  islets 
  within 
  pigmented 
  capsules 
  

   in 
  a 
  single 
  fish. 
  The 
  second 
  point 
  has 
  reference 
  to 
  the 
  intra- 
  

   hepatic 
  pancreas 
  of 
  certain 
  fishes. 
  If 
  the 
  islets 
  are 
  inherent 
  

   portions 
  of 
  the 
  pancreas 
  in 
  such 
  fishes, 
  related 
  directly 
  to 
  its 
  

   functions 
  as 
  a 
  digestive 
  gland, 
  and, 
  according 
  to 
  Jarotsky 
  (6), 
  

   who 
  conducted 
  an 
  extensive 
  series 
  of 
  experiments 
  on 
  white 
  

   mice 
  in 
  dieting 
  and 
  fasting, 
  " 
  they 
  probably 
  supply 
  a 
  sub- 
  

   stance 
  or 
  substances 
  representing 
  a 
  chemical 
  stage 
  of 
  

   development 
  of 
  a 
  ferment 
  or 
  substances 
  necessary 
  to 
  the 
  

   cells 
  producing 
  it," 
  we 
  would 
  expect 
  to 
  find 
  islets 
  in 
  the 
  

   not 
  inconsiderable 
  part 
  of 
  the 
  gland 
  placed 
  inside 
  the 
  liver. 
  

   I 
  have 
  looked 
  carefully 
  for 
  islets 
  in 
  this 
  region 
  in 
  both 
  

   Syngnathus 
  acus 
  and 
  Pleuronectes 
  platessa, 
  and 
  

   have 
  found 
  none. 
  

  

  The 
  view 
  I 
  now 
  bring 
  forward 
  may 
  be 
  stated 
  as 
  follows 
  :■ 
  — 
  The 
  

   conditions 
  observed 
  in 
  various 
  Teleostei 
  force 
  the 
  conclusion 
  

   that 
  here 
  " 
  islet 
  " 
  and 
  pancreas 
  are 
  distinct 
  organs. 
  In 
  certain 
  

  

  VOL. 
  48, 
  PART 
  3. 
  NEW 
  SERIES. 
  29 
  

  

  