﻿26 
  

  

  Dr. 
  A. 
  D. 
  Waller. 
  

  

  to 
  me 
  as 
  having 
  fully 
  established 
  the 
  fact 
  that 
  emotive 
  excitement 
  causes^ 
  

   no 
  alteration 
  of 
  resistance 
  apart 
  from 
  polarisation. 
  

  

  An 
  emotive 
  disturbance 
  of 
  balance 
  shown 
  by 
  the 
  galvanometer 
  on 
  the 
  

   bridge, 
  might 
  be 
  due 
  to 
  a 
  diminution 
  of 
  the 
  electromotive 
  force 
  of 
  polarisation,, 
  

   or 
  to 
  a 
  diminution 
  of 
  the 
  resistance 
  offered 
  by 
  the 
  septum 
  at 
  which 
  polarisa- 
  

   tion 
  is 
  effected 
  ; 
  in 
  either 
  of 
  these 
  cases 
  the 
  balance 
  is 
  restored 
  by 
  a 
  

   diminution 
  of 
  the 
  balancing 
  resistance 
  and 
  the 
  value 
  of 
  the 
  diminution 
  is- 
  

   read 
  in 
  ohms. 
  If 
  a 
  potentiometer 
  is 
  put 
  in 
  series 
  with 
  the 
  subject 
  in 
  the 
  

   4th 
  arm 
  of 
  the 
  bridge 
  as 
  shown 
  by 
  the 
  diagram 
  we 
  shall 
  obtain 
  indications 
  

   that 
  will 
  enable 
  us 
  to 
  decide 
  between 
  the 
  two 
  alternatives 
  — 
  electromotive 
  

   force 
  increased 
  or 
  resistance 
  decreased. 
  If 
  the 
  former 
  a 
  known 
  E.M.F. 
  from 
  

   the 
  potentiometer 
  should 
  give 
  the 
  same 
  deflection 
  before 
  and 
  during 
  an 
  

   emotive 
  change. 
  If 
  the 
  latter 
  the 
  potentiometer 
  deflection 
  should 
  be- 
  

   increased 
  during 
  the 
  emotive 
  change. 
  And 
  in 
  point 
  of 
  fact 
  this 
  second 
  

   alternative 
  is 
  what 
  actually 
  occurs 
  ; 
  whenever 
  I 
  have 
  measured 
  the 
  resistance- 
  

   in 
  ohms 
  before 
  and 
  during 
  emotive 
  excitement, 
  I 
  have 
  found 
  that 
  the- 
  

   potentiometer 
  deflection 
  was 
  inversely 
  proportional 
  with 
  the 
  resistance.- 
  

   The 
  following, 
  e.g., 
  were 
  the 
  scale 
  readings 
  of 
  a 
  particular 
  observation 
  : 
  — 
  

  

  

  Balance. 
  

  

  Potentiometer 
  

   deflection. 
  

  

  Before 
  the 
  emotion 
  effect 
  

  

  During 
  the 
  emotion 
  effect 
  

  

  ohms. 
  

   20,000 
  

   18,000 
  

  

  mm. 
  

   20 
  

   22 
  

  

  The 
  Question 
  of 
  Sweat 
  Nerves. 
  

  

  Differences 
  of 
  resistance 
  of 
  different 
  parts 
  of 
  the 
  skin 
  as 
  well 
  as 
  alterations 
  

   of 
  resistance 
  of 
  a 
  given 
  part, 
  are 
  most 
  easily 
  accounted 
  for 
  by 
  attributing 
  

   them 
  to 
  differences 
  of 
  perspiration. 
  No 
  doubt 
  this 
  simple 
  explanation 
  is- 
  

   sufficient 
  to 
  account 
  for 
  many 
  of 
  the 
  facts 
  of 
  the 
  case, 
  but 
  it 
  does 
  not 
  meet 
  

   the 
  whole 
  case. 
  The 
  skin 
  of 
  the 
  palm 
  of 
  the 
  hand 
  is 
  abundantly 
  provided 
  

   with 
  sweat 
  glands, 
  and 
  perspires 
  freely, 
  but 
  it 
  has 
  a 
  higher 
  and 
  more 
  variable- 
  

   resistance 
  than 
  that 
  of 
  the 
  skin 
  of 
  any 
  other 
  part 
  of 
  the 
  body. 
  The 
  skin 
  of 
  

   the 
  forearm 
  has 
  relatively 
  few 
  sweat 
  glands, 
  and 
  its 
  resistance 
  is 
  lower 
  than 
  

   that 
  of 
  the 
  skin 
  of 
  the 
  palm. 
  Atropine 
  which 
  arrests 
  perspiration 
  by 
  

   paralysing 
  the 
  sudo-motor 
  nerves 
  has, 
  in 
  my 
  experience, 
  no 
  effect 
  whatever 
  

   upon 
  the 
  emotive 
  response. 
  Arrest 
  of 
  the 
  circulation 
  of 
  the 
  limb 
  by 
  an 
  

   Esmarch 
  band 
  does 
  not 
  influence 
  the 
  emotive 
  response. 
  Immersion 
  of 
  the 
  

   hand 
  in 
  hot 
  and 
  cold 
  water 
  do 
  not 
  appreciably 
  affect 
  it. 
  We 
  are 
  forced,. 
  

  

  