﻿Circulation 
  of 
  the 
  Blood. 
  

  

  141 
  

  

  ventricular 
  systole 
  at 
  the 
  heart 
  and 
  the 
  closure 
  of 
  the 
  aortic 
  valve 
  does 
  

   not 
  vary 
  when 
  the 
  pulse-rate 
  is 
  constant, 
  and 
  varies 
  as 
  the 
  square 
  root 
  o£ 
  

   the 
  length 
  of 
  the 
  pulse-beat 
  — 
  being 
  found 
  from 
  the 
  equation 
  xy= 
  20 
  *J 
  x, 
  

   where 
  #=the 
  pulse-rate, 
  and 
  y=the 
  ratio 
  borne 
  by 
  the 
  above-named 
  part 
  

   to 
  the 
  whole 
  beat. 
  

  

  This 
  law, 
  in 
  a 
  somewhat 
  modified 
  form, 
  was 
  enunciated 
  by 
  myself 
  in 
  a 
  

   paper 
  published 
  in 
  the 
  ' 
  Journal 
  of 
  Anatomy 
  and 
  Physiology 
  ' 
  (vol. 
  v» 
  

   p. 
  17), 
  where 
  the 
  peculiarities 
  of 
  the 
  curves 
  taken 
  in 
  the 
  lying 
  posture 
  

   misled 
  me 
  as 
  to 
  the 
  point 
  of 
  commencement 
  of 
  the 
  ventricular 
  systole, 
  

   and 
  led 
  me 
  to 
  state 
  that 
  posture 
  had 
  an 
  effect 
  on 
  the 
  duration 
  of 
  the 
  

   systole. 
  Such, 
  however, 
  is 
  not 
  the 
  case 
  ; 
  for, 
  while 
  lying, 
  the 
  weight 
  of 
  

   the 
  heart 
  is 
  apparently 
  sufficiently 
  great 
  to 
  neutralize 
  the 
  effect 
  on 
  the 
  

   trace 
  of 
  the 
  auricular 
  contraction, 
  and 
  to 
  make 
  the 
  thus 
  taken 
  trace 
  

   deficient 
  in 
  the 
  rise 
  which 
  at 
  other 
  times 
  results 
  from 
  that 
  contraction. 
  

   At 
  all 
  events 
  if 
  this 
  assumption 
  be 
  made, 
  it 
  is 
  found 
  that 
  the 
  lengths 
  of 
  

   the 
  different 
  parts 
  of 
  the 
  beat 
  are 
  not 
  influenced 
  by 
  posture, 
  and 
  they 
  

   agree 
  exactly 
  with 
  the 
  above-stated 
  law. 
  

  

  The 
  following 
  are 
  measurements 
  made 
  since 
  the 
  publication 
  of 
  the 
  

   original 
  paper, 
  which 
  tend 
  fully 
  to 
  confirm 
  the 
  above 
  statement 
  : 
  — 
  

  

  Pulse-rate. 
  

  

  Number 
  of 
  times 
  the 
  

   first 
  part 
  is 
  contained 
  in 
  

   the 
  whole 
  beat. 
  

  

  Calculated 
  ratio 
  

   of 
  first 
  part 
  to 
  whole 
  

   beat 
  on 
  formula 
  

   ay 
  =20 
  \Jx. 
  

  

  46 
  

  

  48 
  

  

  49 
  

  

  52-5 
  

  

  56 
  

  

  57 
  

  

  58 
  

  

  60 
  

  

  64-5 
  

  

  69 
  

  

  74 
  

  

  79 
  

  

  80 
  

  

  81-5 
  

  

  84 
  

  

  85 
  

  

  86 
  

  

  88-5 
  

  

  90-5 
  

  

  92 
  

  

  92 
  

  

  94 
  

  

  2-85 
  

  

  2-71 
  

  

  2-63 
  

  

  2-75 
  

  

  2-65 
  

  

  2-63 
  

  

  2-556 
  

  

  2-45 
  

  

  2-28 
  

  

  2-925 
  

   2-8, 
  2-88 
  

  

  2-23, 
  2-275 
  

   2-24375, 
  2-207 
  

   2-2, 
  2-185, 
  2-093 
  

  

  2-105 
  

   2-09 
  

  

  2-17, 
  2-053 
  

   2-245, 
  2-275 
  

  

  2-0875 
  

   2-14125 
  

  

  2-062 
  

   2-12 
  

  

  2-93 
  

  

  2-885 
  

  

  2-86 
  

  

  2-765 
  

  

  2-675 
  

  

  2-66 
  

  

  2-625 
  

  

  2-59 
  

  

  2-49 
  

  

  2-4 
  

  

  2-325 
  

  

  2-24 
  

  

  2-225 
  

  

  2-2 
  

  

  2-175 
  

  

  2-16 
  

  

  2-155 
  

  

  2-11 
  

  

  2-1 
  

  

  2-09 
  

  

  2-08 
  

  

  2-05 
  

  

  VOL. 
  XXIII. 
  

  

  M 
  

  

  