﻿The 
  Physiological 
  Cost 
  of 
  Muscular 
  Work. 
  

  

  167 
  

  

  In 
  method 
  B, 
  the 
  results 
  are 
  directly 
  read 
  and 
  expressed 
  in 
  terms 
  of 
  CO* 
  

   output 
  as 
  cubic 
  centimetres 
  of 
  C0 
  2 
  per 
  second. 
  The 
  final 
  energy 
  value 
  if 
  

   required 
  is 
  calculated 
  on 
  the 
  assumption 
  of 
  a 
  normal 
  value 
  of 
  the 
  respiratory 
  

   quotient 
  C0 
  2 
  /0 
  2 
  = 
  - 
  85 
  + 
  0'05. 
  It 
  is 
  claimed 
  that 
  the 
  range 
  of 
  error 
  involved 
  

   by 
  A 
  can 
  be 
  reduced 
  to 
  + 
  1 
  per 
  cent., 
  in 
  method 
  B 
  to 
  + 
  5 
  per 
  cent. 
  The 
  

   speed 
  with 
  which 
  useful 
  data 
  can 
  be 
  obtained 
  is 
  much 
  greater 
  by 
  method 
  B 
  

   than 
  by 
  method 
  A.* 
  

  

  Errors 
  of 
  Observation. 
  

  

  Errors 
  of 
  timing, 
  of 
  volume 
  reading, 
  corrections 
  for 
  temperature 
  and 
  pres- 
  

   sure, 
  errors 
  of 
  C0 
  2 
  (and 
  2 
  ) 
  readings, 
  and 
  clerical 
  errors 
  of 
  arithmetic 
  can 
  

   occur 
  by 
  both 
  methods 
  ; 
  their 
  detailed 
  consideration 
  would 
  occupy 
  too 
  much 
  

   space, 
  and 
  must 
  be 
  deferred. 
  I 
  shall 
  assume 
  that 
  due 
  care 
  and 
  accuracy 
  

   have 
  been 
  given 
  to 
  the 
  carrying 
  out 
  of 
  both 
  methods, 
  and 
  consider 
  in 
  detail 
  

   only 
  the 
  error 
  due 
  to 
  the 
  assumption 
  of 
  a 
  normal 
  respiratory 
  quotient 
  which 
  

   forms 
  the 
  essential 
  difference 
  between 
  methods 
  A 
  and 
  B. 
  

  

  In 
  the 
  first 
  place 
  it 
  should 
  be 
  realised 
  as 
  being 
  not 
  an 
  error 
  of 
  observation 
  

   peculiar 
  to 
  method 
  B, 
  but 
  an 
  error 
  of 
  translation, 
  occurring 
  when 
  the 
  

   results 
  measured 
  in 
  terms 
  of 
  cubic 
  centimetres 
  C0 
  2 
  per 
  second 
  are 
  con- 
  

   verted 
  into 
  calories 
  — 
  calories 
  per 
  hour, 
  or 
  calories 
  per 
  square 
  metre 
  per 
  hour. 
  

  

  This 
  error 
  of 
  translation 
  can 
  be 
  evaluated 
  from 
  the 
  following 
  two 
  con- 
  

   siderations 
  : 
  

  

  1. 
  Its 
  maximal 
  (improbable) 
  value 
  with 
  maximal 
  (improbable) 
  fluctuations 
  

   of 
  the 
  C0 
  2 
  /0 
  2 
  quotient, 
  e.g., 
  between 
  07 
  and 
  1*0 
  which 
  are 
  its 
  theoretical 
  

   values 
  on 
  diets 
  exclusively 
  of 
  fat 
  or 
  exclusively 
  of 
  carbohydrates. 
  

  

  2. 
  Its 
  practical 
  (probable 
  )f 
  value 
  with 
  practical 
  (probable) 
  fluctuations 
  of 
  

   the 
  C0 
  2 
  /0 
  2 
  quotient. 
  

  

  1. 
  Its 
  maximal 
  value 
  is 
  to 
  be 
  appreciated 
  from. 
  the 
  following 
  Table 
  of 
  

   Equivalents 
  of 
  1 
  c.c. 
  C0 
  2 
  : 
  — 
  

  

  * 
  With 
  Method 
  B, 
  Miss 
  De 
  Decker's 
  ordinary 
  day's 
  work 
  on 
  dock 
  labourers 
  was, 
  for 
  

   Perry, 
  20 
  readings 
  per 
  day 
  (10 
  double 
  readings), 
  for 
  King 
  and 
  others 
  only 
  10 
  per 
  day. 
  

   But 
  in 
  the 
  laboratory 
  when 
  getting 
  out 
  C0 
  2 
  curves, 
  she 
  has 
  worked 
  up 
  to 
  80 
  per 
  day. 
  

   None 
  of 
  her 
  hourly 
  readings 
  on 
  labourers 
  has 
  been 
  rejected 
  or 
  amended. 
  The 
  net 
  

   expenditure 
  of 
  time 
  at 
  the 
  docks 
  and 
  at 
  Smithfield 
  was 
  27 
  days 
  and 
  6 
  nights, 
  and 
  the 
  

   data 
  collected 
  have 
  not 
  involved 
  the 
  employment 
  of 
  an 
  expert 
  computer. 
  By 
  Method 
  B, 
  

   Greenwood 
  obtained 
  a 
  total 
  number 
  of 
  226 
  readings 
  during 
  the 
  period 
  November, 
  1918, 
  

   to 
  March, 
  1919, 
  upon 
  43 
  subjects 
  engaged 
  upon 
  various 
  kinds 
  of 
  work. 
  

  

  t 
  Not 
  probable 
  error 
  in 
  the 
  technical 
  statistical 
  sense. 
  My 
  data 
  are 
  not 
  numerous 
  

   enough 
  for 
  calculation 
  of 
  " 
  probable 
  error." 
  

  

  