﻿24 
  

  

  Dr. 
  A. 
  D. 
  Waller. 
  

  

  2 
  L 
  is 
  found 
  to 
  be 
  5 
  mm. 
  The 
  electromotive 
  value 
  of 
  the 
  emotive 
  response 
  

   is 
  then 
  + 
  1 
  L 
  or 
  l 
  - 
  4 
  volts. 
  Its 
  conductance 
  value 
  is 
  25 
  7 
  by 
  direct 
  reading 
  of 
  

   the 
  deflection 
  or 
  a 
  rise 
  of 
  conductance 
  from 
  50 
  to 
  75 
  7 
  ( 
  or 
  reciprocated 
  into 
  

   terms 
  of 
  resistance 
  = 
  a 
  fall 
  of 
  resistance 
  from 
  20,000 
  to 
  13,333 
  ohms, 
  i.e., 
  a 
  

   fall 
  of 
  6667 
  ohms). 
  

  

  This 
  fall 
  of 
  resistance 
  can 
  of 
  course 
  be 
  tested 
  by 
  the 
  balancing 
  resistance, 
  

   but 
  only 
  approximately, 
  because 
  it 
  is 
  a 
  diminishing 
  diminution 
  ; 
  in 
  the 
  

   present 
  example 
  it 
  would 
  be 
  found 
  between 
  6500 
  and 
  6000 
  ohms. 
  There- 
  

   fore 
  it 
  is 
  preferable 
  to 
  take 
  out 
  directly 
  the 
  conductance 
  values 
  of 
  deflections 
  

   with 
  a 
  properly 
  calibrated 
  instrument. 
  

  

  § 
  2. 
  Method. 
  — 
  By 
  means 
  of 
  a 
  recording 
  galvanometer 
  set 
  up 
  in 
  my 
  

   dressing 
  room, 
  I 
  took 
  photographic 
  records 
  for 
  short 
  periods 
  (as 
  a 
  rule 
  two 
  

   minutes, 
  sometimes 
  longer) 
  of 
  the 
  conductance 
  of 
  my 
  left 
  palm 
  (sometimes 
  

   also 
  of 
  other 
  parts) 
  at 
  all 
  hours 
  of 
  the 
  day 
  and 
  night 
  as 
  happened 
  to 
  be 
  con- 
  

   venient, 
  and 
  plotted 
  the 
  results 
  during 
  a 
  series 
  of 
  days. 
  Eecords 
  were 
  also 
  

   taken 
  when 
  possible 
  of 
  other 
  parts, 
  such 
  as 
  the 
  forearm, 
  leg, 
  and 
  foot, 
  for 
  

   comparison 
  with 
  the 
  palm 
  or 
  skin, 
  which, 
  as 
  stated 
  in 
  my 
  previous 
  communi- 
  

   cation, 
  is 
  the 
  principal 
  instrument 
  of 
  emotive 
  response. 
  

  

  The 
  hand, 
  galvanometer 
  (suitably 
  shunted), 
  and 
  two 
  Leclanche 
  cells 
  were 
  

   put 
  up 
  in 
  series, 
  the 
  galvanometer 
  being 
  adjusted 
  by 
  shunt 
  so 
  that 
  a 
  cali- 
  

   brating 
  deflection 
  through 
  a 
  resistance 
  of 
  20,000 
  ohms 
  (= 
  a 
  conductance 
  

   of 
  50 
  7) 
  measured 
  on 
  the 
  photographic 
  plate 
  as 
  nearly 
  as 
  possible 
  50 
  mm. 
  

   (i.e., 
  17 
  = 
  1 
  mm. 
  multiples 
  and 
  submultiples 
  of 
  this 
  adjustment 
  were 
  taken 
  

   when 
  required). 
  

  

  In 
  the 
  first 
  two 
  series 
  of 
  observations 
  (Tables 
  I 
  and 
  II) 
  the 
  electrodes 
  

   (zinc 
  discs 
  10 
  cm. 
  2 
  , 
  covered 
  by 
  chamois 
  leather 
  moistened 
  with 
  - 
  6 
  per 
  cent. 
  

   NaCl 
  solution) 
  were 
  fixed 
  to 
  the 
  palm 
  and 
  back 
  of 
  the 
  hand 
  by 
  elastic 
  bands. 
  

   For 
  the 
  third 
  series 
  (Table 
  III) 
  one 
  electrode 
  was 
  slipped 
  behind 
  the 
  closed 
  

   lips 
  against 
  the 
  tip 
  of 
  the 
  tongue, 
  and 
  the 
  other 
  fixed 
  to 
  the 
  palm 
  as 
  before, 
  

   or 
  used 
  as 
  an 
  exploring 
  electrode 
  for 
  other 
  parts 
  against 
  which 
  it 
  was 
  firmly 
  

   held 
  at 
  the 
  end 
  of 
  an 
  insulating 
  handle 
  by 
  the 
  free 
  hand. 
  

  

  This 
  second 
  or 
  unipolar 
  plan 
  was 
  adopted 
  not 
  only 
  as 
  a 
  simplification 
  for 
  

   the 
  summary 
  comparison 
  of 
  different 
  parts, 
  but 
  also 
  in 
  order 
  to 
  diminish 
  the 
  

   risk 
  of 
  surface 
  conduction 
  between 
  adjacent 
  electrodes. 
  I 
  considered 
  that 
  an 
  

   electrode 
  in 
  the 
  mouth 
  would 
  be 
  equivalent 
  to 
  an 
  electrode 
  applied 
  to 
  the 
  

   internal 
  surface 
  of 
  the 
  skin, 
  and 
  be 
  of 
  negligible 
  resistance 
  as 
  compared 
  with 
  

   the 
  resistance 
  of 
  a 
  second 
  area 
  of 
  skin. 
  In 
  justification 
  of 
  this 
  presumption, 
  

  

  1 
  measured 
  the 
  resistance 
  offered 
  by 
  : 
  

  

  