﻿328 
  Dr. 
  M. 
  Foster 
  and 
  Mr. 
  A. 
  G. 
  Dew-Smith 
  on 
  the 
  [Mar. 
  18, 
  

  

  The 
  greater 
  mass 
  of 
  the 
  contractile 
  tissue 
  of 
  the 
  ventricle 
  lies 
  towards 
  

   the 
  auricular 
  end. 
  If 
  the 
  ventricle 
  were 
  supposed 
  to 
  be 
  bisected 
  trans- 
  

   versely 
  by 
  a 
  straight 
  line 
  drawn 
  across 
  it, 
  and 
  its 
  constituent 
  fibres 
  

   regarded 
  as 
  so 
  many 
  straight 
  lines, 
  representing 
  so 
  many 
  forces, 
  those 
  

   forces 
  might 
  be 
  considered 
  as 
  applied 
  at 
  a 
  point 
  on 
  the 
  auricular 
  side 
  of 
  

   that 
  straight 
  line. 
  

  

  If 
  we, 
  then, 
  suppose 
  (we 
  shall 
  presently 
  state 
  our 
  reasons 
  for 
  such 
  a 
  

   supposition) 
  that 
  the 
  rhythmic 
  impulse 
  is 
  generated 
  by 
  changes 
  in 
  all 
  the 
  

   fibres, 
  that 
  impulse 
  would 
  naturally 
  manifest 
  itself 
  first, 
  as 
  in 
  fact 
  it 
  does, 
  

   at 
  the 
  auricular 
  end. 
  

  

  Moreover, 
  since 
  the 
  heart 
  was 
  first 
  formed, 
  each 
  beat 
  has 
  been 
  taking 
  

   place 
  after 
  a 
  fixed 
  normal 
  fashion, 
  beginning 
  at 
  the 
  auricular 
  end. 
  Hence 
  

   the 
  nutrition, 
  the 
  life 
  (let 
  it 
  be 
  called 
  what 
  it 
  may) 
  of 
  each 
  part 
  is 
  habi- 
  

   tuated 
  and 
  regulated 
  to 
  such 
  conditions 
  as 
  are 
  involved 
  iu 
  the 
  normal 
  

   beat 
  beginning 
  at 
  the 
  auricular 
  end. 
  One 
  would 
  therefore 
  expect 
  that, 
  

   even 
  under 
  abnormal 
  conditions, 
  it 
  would 
  be 
  easier 
  to 
  call 
  forth 
  a 
  beat 
  

   beginning 
  at 
  the 
  auricular 
  end 
  than 
  at 
  the 
  aortic 
  end, 
  and 
  that 
  when 
  

   the 
  heart 
  is 
  divided 
  into 
  two 
  pieces 
  the 
  auricular 
  end 
  would 
  manifest 
  a 
  

   rhythmic 
  beat 
  more 
  readily 
  than 
  the 
  aortic 
  end, 
  though 
  each 
  end 
  were 
  

   absolutely 
  possessed 
  of 
  the 
  power 
  of 
  rhythmic 
  pulsation. 
  

  

  This 
  is 
  actually 
  the 
  case. 
  The 
  aortic 
  end, 
  separated 
  from 
  the 
  auricular 
  

   end, 
  will, 
  under 
  favourable 
  circumstances, 
  beat 
  spontaneously, 
  but 
  will 
  

   not 
  do 
  so 
  with 
  the 
  same 
  readiness 
  as 
  will 
  the 
  auricular 
  end. 
  Under 
  the 
  

   influence 
  of 
  the 
  constant 
  current, 
  the 
  beats 
  of 
  a 
  spontaneously 
  beating 
  

   heart 
  may 
  be 
  made 
  to 
  begin 
  at 
  and 
  be 
  confined 
  to 
  either 
  the 
  aortic 
  or 
  the 
  

   auricular 
  end, 
  but 
  not 
  indifferently 
  ; 
  they 
  appear 
  most 
  readily 
  at 
  the 
  

   auricular 
  end. 
  Under 
  the 
  influence 
  of 
  the 
  constant 
  current, 
  the 
  heart, 
  

   otherwise 
  at 
  rest, 
  may 
  be 
  made 
  to 
  beat 
  spontaneously 
  at 
  the 
  auricular 
  

   end, 
  but 
  not 
  at 
  all, 
  or 
  with 
  great 
  difficulty, 
  at 
  the 
  aortic 
  end. 
  

  

  So 
  far 
  concerning 
  the 
  action 
  of 
  the 
  constant 
  current 
  on 
  the 
  ventricle 
  

   at 
  rest. 
  

  

  We 
  have 
  already 
  been 
  led 
  to 
  anticipate 
  some 
  of 
  the 
  results 
  gained 
  by 
  

   applying 
  the 
  constant 
  current 
  to 
  a 
  heart 
  spontaneously 
  beating. 
  

  

  These 
  are 
  somewhat 
  more 
  difficult 
  to 
  analyze, 
  on 
  account 
  of 
  the 
  greater 
  

   susceptibility 
  of 
  the 
  tissue, 
  and 
  the 
  greater 
  variations 
  in 
  irritability 
  result- 
  

   ing 
  from 
  treatment. 
  

  

  Thus, 
  when 
  the 
  current 
  used 
  is 
  one 
  so 
  strong 
  that 
  the 
  momentary 
  appli- 
  

   cation 
  of 
  it 
  is 
  followed 
  by 
  a 
  powerful 
  contraction, 
  it 
  is 
  evident 
  that 
  in 
  

   dealing 
  with 
  the 
  effects 
  of 
  the 
  same 
  current 
  applied 
  for 
  several 
  seconds, 
  we 
  

   have 
  to 
  consider 
  that 
  the 
  powerful 
  initial 
  " 
  making 
  " 
  contraction 
  must 
  in- 
  

   fluence, 
  by 
  the 
  reactions 
  following 
  it, 
  the 
  behaviour 
  of 
  the 
  heart 
  during 
  the 
  

   passage 
  of 
  the 
  current. 
  In 
  the 
  same 
  way 
  the 
  breaking 
  of 
  the 
  current 
  

   will 
  be 
  followed 
  by 
  events 
  the 
  causes 
  of 
  which 
  are 
  sought 
  for 
  partly 
  

   in 
  the 
  reaction 
  following 
  upon 
  the 
  strong 
  contraction 
  caused 
  by 
  the 
  

   break. 
  

  

  