﻿1875.] 
  Influence 
  of 
  Electricity 
  on 
  the 
  Hearts 
  of 
  Mollusks. 
  325 
  

  

  a 
  nerve, 
  and 
  the 
  support 
  they 
  thus 
  afford 
  to 
  Pfliiger's 
  hypothesis, 
  that 
  

   the 
  establishment 
  of 
  kathelectrotonus 
  and 
  the 
  disappearance 
  of 
  anelec- 
  

   trotonus 
  alone 
  set 
  in 
  motion 
  a 
  stimulus-wave. 
  

  

  When 
  the 
  ventricle 
  and 
  auricle 
  are 
  removed 
  together 
  from 
  the 
  body, 
  

   and 
  placed 
  between 
  the 
  electrodes, 
  so 
  that 
  one 
  electrode 
  lies 
  at 
  the 
  aortic 
  

   end 
  of 
  the 
  ventricle 
  and 
  the 
  other 
  at 
  the 
  pulmonary 
  end 
  of 
  the 
  auricle, 
  

   the 
  ventricle 
  behaves, 
  as 
  far 
  as 
  the 
  make- 
  and 
  break-beats 
  are 
  concerned, 
  

   very 
  much 
  as 
  if 
  the 
  electrodes 
  were 
  applied 
  directly 
  to 
  the 
  ventricle 
  alone. 
  

   Thus 
  when 
  the 
  kathode 
  is 
  at 
  the 
  auricle 
  there 
  is 
  a 
  " 
  making 
  "-beat 
  at 
  the 
  

   auricular 
  end 
  of 
  the 
  ventricle 
  and 
  a 
  " 
  breaking 
  "-beat 
  at 
  the 
  aorta, 
  and 
  

   vice 
  versa. 
  

  

  We 
  have 
  satisfied 
  ourselves 
  by 
  numerons 
  observations 
  that, 
  provided 
  

   the 
  contraction 
  of 
  the 
  auricle 
  causes 
  no 
  distension 
  of 
  the 
  ventricle, 
  the 
  

   condition 
  of 
  the 
  one 
  chamber 
  of 
  the 
  heart 
  has 
  no 
  effect 
  on 
  that 
  of 
  the 
  

   other. 
  Between 
  the 
  two 
  is 
  a 
  small 
  ring 
  of 
  a 
  sort 
  of 
  connective 
  tissue, 
  

   traversed, 
  as 
  far 
  as 
  we 
  can 
  make 
  out, 
  by 
  no 
  nerves, 
  which 
  affords 
  com- 
  

   plete 
  physiological 
  isolation 
  of 
  the 
  two 
  chambers. 
  Thus 
  out 
  of 
  the 
  body, 
  

   empty 
  of 
  blood, 
  auricle 
  and 
  ventricle 
  are 
  two 
  independent 
  organs. 
  Hence 
  

   when 
  a 
  current 
  is 
  passed 
  in 
  the 
  manner 
  described 
  through 
  both 
  ventricle 
  

   and 
  auricle, 
  each 
  part 
  undergoes 
  a 
  separate 
  physiological 
  polarization, 
  the 
  

   auricular 
  end 
  of 
  the 
  ventricle 
  becoming 
  kathodic 
  or 
  anodic 
  as 
  the 
  case 
  

   may 
  be, 
  just 
  as 
  if 
  the 
  current 
  were 
  applied 
  to 
  the 
  ventricle 
  alone, 
  account 
  

   being 
  taken 
  of 
  the 
  weakening 
  of 
  the 
  current 
  through 
  the 
  additional 
  re- 
  

   sistance 
  offered 
  by 
  the 
  auricle. 
  This, 
  at 
  least, 
  is 
  the 
  only 
  explanation 
  we 
  

   can 
  give 
  of 
  the 
  undoubted 
  fact, 
  that, 
  with 
  some 
  modifications 
  to 
  be 
  men- 
  

   tioned 
  afterwards, 
  the 
  effect 
  of 
  the 
  constant 
  current 
  is 
  the 
  same 
  on 
  the 
  

   ventricle 
  with 
  the 
  auricle 
  attached 
  as 
  on 
  the 
  ventricle 
  alone. 
  

  

  Besides 
  the 
  mere 
  occurrence 
  of 
  the 
  kathodic 
  making- 
  and 
  the 
  anodic 
  

   breaking-beat, 
  there 
  are 
  several 
  facts 
  worthy 
  of 
  attention. 
  These 
  we 
  

   have 
  studied 
  chiefly 
  on 
  the 
  ventricle 
  with 
  the 
  auricle 
  attached 
  ; 
  but 
  we 
  

   see 
  no 
  reason 
  to 
  doubt 
  that 
  the 
  same 
  facts 
  appear 
  when 
  the 
  ventricle 
  

   alone 
  is 
  used. 
  

  

  When 
  the 
  period 
  during 
  which 
  the 
  current 
  passes 
  'is 
  very 
  short, 
  when 
  

   the 
  current 
  is 
  very 
  rapidly 
  made 
  and 
  broken, 
  the 
  two 
  contractions 
  are 
  

   replaced 
  by 
  one. 
  This 
  contraction 
  or 
  beat 
  begins 
  at 
  the 
  kathode, 
  i. 
  e. 
  is 
  

   aortic 
  or 
  auricular 
  according 
  to 
  the 
  position 
  of 
  that 
  electrode. 
  

  

  Here, 
  again, 
  is 
  a 
  curious 
  parallel 
  to 
  the 
  view 
  so 
  generally 
  adopted 
  in 
  

   reference 
  to 
  the 
  behaviour 
  of 
  nerves 
  towards 
  the 
  constant 
  current, 
  viz. 
  

   that 
  the 
  establishment 
  of 
  kathelectrotonus 
  is 
  a 
  stronger 
  stimulus 
  than 
  

   the 
  disappearance 
  of 
  anelectrotonus. 
  

  

  When 
  exceedingly 
  feeble 
  currents 
  are 
  employed, 
  it 
  frequently 
  happens 
  

   that 
  a 
  momentary 
  application 
  of 
  the 
  current, 
  a 
  rapid 
  make 
  and 
  break, 
  

   produces 
  no 
  contraction 
  or 
  beat. 
  Nevertheless 
  such 
  a 
  current, 
  if 
  applied 
  

   for 
  several 
  seconds, 
  will 
  give, 
  as 
  usual, 
  a 
  kathodic 
  making- 
  and 
  an 
  anodic 
  

   breaking-beat. 
  

  

  