﻿330 
  Dr. 
  M. 
  Foster 
  and 
  Mr. 
  A. 
  G. 
  Dew-Smith 
  on 
  the 
  [Mar. 
  18, 
  

  

  This 
  difference 
  is 
  most 
  readily 
  observed 
  when 
  the 
  ventricle 
  with 
  the 
  

   auricle 
  attached 
  is 
  placed 
  between 
  the 
  electrodes 
  than 
  when 
  the 
  ventricle 
  

   alone 
  is 
  subjected 
  to 
  the 
  action 
  of 
  the 
  current, 
  though 
  we 
  have 
  observed 
  

   the 
  same 
  phenomena 
  in 
  the 
  latter 
  case 
  also. 
  

  

  When 
  the 
  anode 
  is 
  placed 
  at 
  the 
  aorta, 
  and 
  the 
  kathode 
  at 
  the 
  auricle, 
  

   a 
  very 
  feeble 
  current 
  produces 
  no 
  appreciable 
  effect, 
  except 
  that 
  perhaps 
  

   the 
  beats 
  are 
  rather 
  feebler 
  and 
  somewhat 
  quicker 
  (fig. 
  5, 
  p. 
  342). 
  

  

  The 
  same 
  current, 
  applied 
  to 
  the 
  same 
  heart 
  in 
  the 
  opposite 
  direction 
  

   (that 
  is, 
  with 
  the 
  kathode 
  at 
  the' 
  aorta 
  and 
  the 
  anode 
  at 
  the 
  auricle), 
  

   distinctly 
  inhibits 
  the 
  ventricle, 
  so 
  that 
  it 
  remains 
  in 
  diastole 
  during 
  the 
  

   whole 
  time 
  of 
  the 
  passage 
  of 
  the 
  current, 
  and 
  resumes 
  its 
  beat 
  on 
  the 
  

   current 
  being 
  broken. 
  

  

  This 
  inhibition 
  is 
  very 
  clearly 
  shown 
  in 
  fig. 
  7. 
  Here 
  advantage 
  was 
  

   taken 
  of 
  a 
  curious 
  secondary 
  rhythm 
  (fig. 
  6), 
  which 
  we 
  have 
  had 
  more 
  

   than 
  one 
  opportunity 
  of 
  witnessiug. 
  The 
  ventricle, 
  after 
  a 
  period 
  of 
  

   quiescence, 
  began 
  to 
  beat, 
  at 
  first 
  feebly 
  with 
  long 
  pauses, 
  then 
  more 
  

   rapidly 
  and 
  strongly. 
  Having 
  reached 
  a 
  maximum, 
  the 
  beats 
  similarly 
  

   declined, 
  and 
  thus 
  a 
  new 
  period 
  of 
  quiescence 
  was 
  again 
  begun. 
  This 
  

   alternation 
  of 
  rhythmic 
  beats 
  and 
  quiescence 
  was 
  observed 
  for 
  a 
  long 
  

   time. 
  

  

  It 
  will 
  be 
  seen 
  that 
  when 
  the 
  constant 
  current 
  (which 
  was 
  exceedingly 
  

   weak, 
  inasmuch 
  as 
  the 
  resistance-circuit 
  only 
  offered 
  a 
  single 
  ohm, 
  or 
  

   even 
  only 
  a 
  fraction 
  of 
  an 
  ohm 
  resistance) 
  was 
  thrown 
  into 
  the 
  heart 
  at 
  

   one 
  of 
  the 
  ventricle's 
  beating 
  periods, 
  no 
  effect 
  was 
  produced 
  when 
  the 
  

   anode 
  was 
  at 
  the 
  aorta, 
  but 
  distinct 
  inhibition 
  when 
  the 
  kathode 
  was 
  at 
  

   the 
  aorta. 
  

  

  During 
  the 
  period 
  of 
  quiescence 
  the 
  effect 
  of 
  the 
  current 
  is 
  very 
  much 
  

   what 
  we 
  have 
  already 
  described 
  as 
  that 
  of 
  the 
  constant 
  current 
  on 
  a 
  ven- 
  

   tricle 
  which 
  has 
  ceased 
  beating, 
  viz. 
  that 
  when 
  the 
  anode 
  is 
  at 
  the 
  aorta, 
  

   and 
  when, 
  consequently, 
  the 
  auricular 
  end 
  of 
  the 
  ventricle 
  becomes 
  

   kathodic, 
  a 
  rhythmic 
  beat 
  tends 
  to 
  make 
  its 
  appearance, 
  but 
  when 
  the 
  

   auricular 
  end 
  is 
  made 
  anodic, 
  no 
  beats 
  make 
  their 
  appearance 
  (fig. 
  8). 
  

  

  The 
  explanation 
  we 
  would 
  give 
  of 
  these 
  facts 
  (very 
  similar 
  to 
  that 
  given 
  

   at 
  p. 
  328) 
  is 
  as 
  follows 
  : 
  — 
  

  

  The 
  current 
  employed 
  was 
  a 
  very 
  feeble 
  one, 
  rendered 
  all 
  the 
  more 
  

   feeble, 
  as 
  far 
  as 
  its 
  effect 
  on 
  the 
  ventricle 
  was 
  concerned, 
  by 
  the 
  fact 
  of 
  

   some 
  of 
  it 
  haviug 
  been 
  occupied 
  in 
  effecting 
  the 
  polarization 
  of 
  the 
  

   auricle. 
  

  

  When 
  the 
  kathode 
  is 
  placed 
  at 
  the 
  aorta, 
  the 
  auricular 
  end 
  of 
  the 
  ven- 
  

   tricle 
  becomes 
  anodic. 
  Hence, 
  as 
  we 
  have 
  already 
  seen, 
  the 
  beats 
  would, 
  

   if 
  the 
  current 
  were 
  of 
  a 
  sufficient 
  intensity, 
  while 
  absent 
  at 
  the 
  auricular 
  

   end, 
  be 
  present 
  at 
  and 
  start 
  from 
  the 
  aortic 
  end. 
  We 
  have 
  already 
  seen 
  

   that 
  the 
  auricular 
  end 
  is 
  more 
  sensitive 
  than 
  the 
  aortic 
  end. 
  Hence, 
  with 
  

   a 
  sufficiently 
  weak 
  current, 
  as 
  in 
  the 
  case 
  in 
  point, 
  the 
  auricular 
  end 
  being 
  

   more 
  affected 
  than 
  the 
  aortic 
  end, 
  the 
  beats 
  are 
  inhibited 
  at 
  the 
  auricular 
  

  

  