﻿500 
  On 
  the 
  Anatomy 
  of 
  the 
  Umbilical 
  Cord. 
  [June 
  17, 
  

  

  I 
  have 
  not 
  been 
  able 
  to 
  discover 
  any 
  nerve-fibres 
  in 
  the 
  cord. 
  

  

  The 
  canalicular 
  tissue 
  may 
  be 
  demonstrated 
  to 
  end 
  in 
  three 
  coues, 
  

   one 
  for 
  each 
  column 
  of 
  the 
  cord, 
  the 
  apices 
  of 
  which 
  are 
  just 
  within 
  the 
  

   dermal 
  ring. 
  The 
  injection 
  will 
  not 
  pass 
  through 
  the 
  tendinous 
  ring 
  ; 
  

   nor 
  have 
  I 
  succeeded 
  in 
  making 
  it 
  enter 
  the 
  capillaries 
  of 
  the 
  cord 
  from, 
  

   the 
  canalicular 
  tissue. 
  

  

  "When 
  the 
  injection 
  of 
  the 
  capillary 
  plexus 
  running 
  from 
  the 
  dermal 
  

   ring 
  has 
  been 
  successfully 
  accomplished 
  (and 
  this 
  is, 
  for 
  many 
  reasons, 
  a 
  

   difficult 
  thing 
  to 
  do), 
  there 
  will 
  be 
  found 
  a 
  peculiar 
  vascular 
  arrangement 
  

   in 
  the 
  centre 
  of 
  the 
  cord, 
  lying 
  in 
  the 
  firm 
  nucleated 
  tissue 
  which 
  forms 
  

   the 
  omphalic 
  ring. 
  The 
  basis 
  of 
  this 
  arrangement 
  is 
  a 
  peculiar 
  sacculated 
  

   sinus, 
  a 
  mere 
  excavation 
  in 
  the 
  fibrous 
  tissue, 
  as 
  it 
  is 
  doubtful 
  if 
  it 
  has 
  

   any 
  definite 
  wall. 
  It 
  seems 
  to 
  have 
  a 
  spiral 
  arrangement, 
  for 
  in 
  one 
  

   section 
  it 
  appears 
  and 
  disappears 
  as 
  only 
  a 
  screw 
  could. 
  

  

  It 
  extends 
  from 
  the 
  omphalic 
  ring 
  at 
  least 
  forty-five 
  millims. 
  up 
  into 
  

   the 
  true 
  substance 
  of 
  the 
  cord, 
  giving 
  off 
  at 
  short 
  intervals 
  thick 
  trunks 
  

   which 
  rapidly 
  break 
  up 
  into 
  capillaries. 
  

  

  These 
  capillaries 
  do 
  not 
  form 
  loops, 
  but 
  enter 
  directly 
  into 
  the 
  canali- 
  

   cular 
  tissue 
  ; 
  and 
  it 
  is 
  possible 
  to 
  inject 
  a 
  large 
  extent 
  of 
  all 
  three 
  dis- 
  

   tricts 
  of 
  the 
  substance 
  of 
  the 
  cord 
  by 
  passing 
  the 
  injection 
  through 
  the 
  

   foetus. 
  This 
  sinus 
  seems 
  to 
  originate 
  from 
  the 
  small 
  arteries 
  of 
  the 
  

   anterior 
  abdominal 
  wall, 
  which 
  enter 
  with 
  the 
  vein. 
  

  

  There 
  seems 
  to 
  be 
  a 
  close 
  analogy 
  between 
  this 
  arrangement 
  and 
  that 
  

   of 
  the 
  Haversian 
  system 
  in 
  bones 
  ; 
  indeed 
  the 
  actual 
  resemblance 
  some- 
  

   times 
  seen 
  is 
  very 
  close. 
  

  

  IV. 
  The 
  proper 
  tissue 
  of 
  the 
  vessels 
  is 
  made 
  up 
  of 
  the 
  ordinary 
  fusi- 
  

   form 
  fibre-cells, 
  with 
  their 
  characteristic 
  rod-shaped 
  oval 
  nuclei. 
  The 
  

   outer 
  layers 
  seem 
  to 
  have 
  wider 
  limits 
  of 
  contraction 
  than 
  the 
  inner 
  — 
  

   these 
  latter 
  being 
  thrown 
  into 
  rugose 
  folds 
  on 
  the 
  contraction 
  of 
  the 
  

   arteries, 
  resembling 
  the 
  appearance 
  of 
  the 
  contracted 
  urethra 
  or 
  oeso- 
  

   phagus. 
  One 
  reason 
  of 
  this 
  exceptional 
  range 
  of 
  contraction 
  is, 
  that 
  

   the 
  fibres 
  of 
  the 
  muscular 
  tissue 
  are 
  arranged 
  in 
  bundles 
  having 
  a 
  

   double 
  spiral 
  direction. 
  The 
  contraction 
  of 
  the 
  fibres 
  seems 
  to 
  be 
  governed 
  

   by 
  the 
  blood-current/ 
  as 
  they 
  contract 
  as 
  soon 
  as 
  the 
  blood 
  in 
  them 
  

   becomes 
  arterial 
  by 
  the 
  establishment 
  of 
  respiration 
  ; 
  and 
  they 
  may 
  be 
  

   seen 
  again 
  to 
  relax 
  and 
  pulsate 
  if 
  the 
  blood 
  becomes 
  again 
  venous 
  by 
  the 
  

   temporary 
  arrest 
  of 
  respiration. 
  

  

  This 
  appears 
  to 
  be 
  aided 
  by 
  the 
  absence 
  of 
  an 
  endothelial 
  lining 
  to 
  the 
  

   arteries, 
  which 
  my 
  observations 
  seem 
  to 
  establish. 
  

  

  The 
  closure 
  of 
  the 
  vessels 
  is 
  effected 
  immediately 
  by 
  clot, 
  and 
  subse- 
  

   quently 
  by 
  the 
  agency 
  of 
  the 
  round 
  migratory 
  cells. 
  

  

  These 
  wandering 
  cells 
  seem 
  also 
  to 
  share 
  in 
  the 
  subsequent 
  processes 
  

   of 
  inflammatory 
  ulceration 
  and 
  necrosis 
  of 
  the 
  stump 
  of 
  the 
  cord, 
  and 
  in 
  

   the 
  removal 
  of 
  the 
  coats 
  of 
  the 
  remaining 
  vessels. 
  

  

  V, 
  The 
  relation 
  of 
  the 
  cord 
  to 
  the 
  foetus 
  has 
  already 
  been 
  described. 
  

  

  