﻿188 
  Surgeon-Major 
  F. 
  de 
  Chaumont 
  on 
  the 
  [Jan. 
  28, 
  

  

  that, 
  general 
  diffusion 
  in 
  an 
  air-space 
  beiug 
  admitted, 
  the 
  same 
  amount 
  

   of 
  air 
  was 
  required 
  to 
  ventilate 
  it, 
  whatever 
  its 
  size 
  might 
  be. 
  In 
  

   another 
  paper, 
  published 
  in 
  the 
  ' 
  Edinburgh 
  Medical 
  Journal 
  ' 
  in 
  May 
  

   1867, 
  1 
  went 
  into 
  the 
  subject 
  with 
  the 
  view 
  of 
  pointing 
  out 
  that 
  we 
  might, 
  

   with 
  existing 
  data, 
  establish 
  a 
  basis, 
  which 
  should 
  be 
  both 
  scientific 
  and 
  

   practical, 
  for 
  estimating 
  the 
  amount 
  of 
  air 
  required 
  ; 
  and 
  I 
  adduced 
  some 
  

   results 
  to 
  show 
  that 
  the 
  evidence 
  of 
  the 
  senses 
  might 
  be 
  employed 
  (if 
  used 
  

   with 
  proper 
  care 
  and 
  precautions) 
  as 
  the 
  ground-work 
  of 
  a 
  scale, 
  and 
  gave 
  

   a 
  short 
  table 
  of 
  the 
  amounts 
  of 
  respiratory 
  impurity 
  (estimated 
  as 
  C0 
  2 
  ) 
  

   which 
  corresponded 
  to 
  certain 
  conditions 
  noted 
  as 
  affecting 
  the 
  sense 
  of 
  

   smell. 
  This 
  paper 
  attracted 
  the 
  attention 
  of 
  General 
  Morin, 
  who 
  made 
  

   it 
  the 
  text 
  of 
  a 
  short 
  article 
  in 
  the 
  Journal 
  of 
  the 
  Conservatoire 
  des 
  Arts 
  

   et 
  Metiers 
  during 
  last 
  year. 
  Since 
  the 
  publication 
  of 
  my 
  paper 
  in 
  1867 
  

   I 
  have 
  accumulated 
  more 
  data 
  ; 
  and 
  the 
  number 
  of 
  observations 
  being 
  now 
  

   sufficient 
  to 
  give 
  at 
  least 
  a 
  fair 
  approximation 
  to 
  the 
  truth, 
  I 
  beg 
  to 
  call 
  

   attention 
  to 
  the 
  results. 
  

  

  It 
  is 
  generally 
  admitted 
  that 
  it 
  is 
  organic 
  matter, 
  either 
  suspended 
  or 
  

   in 
  the 
  form 
  of 
  vapour, 
  that 
  is 
  the 
  poison 
  in 
  air 
  rendered 
  impure 
  by 
  the 
  

   products 
  of 
  respiration. 
  It 
  is 
  also 
  admitted 
  that 
  it 
  is 
  the 
  same 
  substance 
  

   that 
  gives 
  the 
  disagreeable 
  sensation 
  described 
  as 
  " 
  closeness 
  " 
  in 
  an 
  ill- 
  

   ventilated 
  air-space. 
  Although 
  the 
  nature 
  of 
  the 
  organic 
  matter 
  may 
  

   vary 
  to 
  a 
  certain 
  extent, 
  it 
  will 
  be 
  allowed 
  that 
  a 
  condition 
  of 
  good 
  ven- 
  

   tilation 
  may 
  be 
  established 
  if 
  we 
  dilute 
  the 
  air 
  sufficiently 
  with 
  fresh 
  air, 
  

   so 
  that 
  the 
  amount 
  of 
  organic 
  matter 
  shall 
  not 
  vary 
  sensibly 
  from 
  that 
  of 
  

   the 
  external 
  air. 
  Unfortunately 
  all 
  the 
  methods 
  devised 
  for 
  the 
  deter- 
  

   mination 
  of 
  organic 
  matter 
  in 
  air 
  are 
  both 
  difficult 
  and 
  unsatisfactory, 
  so 
  

   much 
  so 
  that 
  they 
  are 
  almost 
  practically 
  impossible 
  in 
  a 
  ventilation 
  inquiry. 
  

   Observations, 
  however, 
  as 
  far 
  as 
  they 
  have 
  gone, 
  seem 
  to 
  show 
  that 
  the 
  

   amount 
  of 
  organic 
  impurity 
  bears 
  a 
  fairly 
  regular 
  proportion 
  to 
  the 
  

   amount 
  of 
  carbonic 
  acid 
  evolved 
  by 
  the 
  inhabitant 
  in 
  an 
  air-space 
  ; 
  and 
  as 
  

   the 
  latter 
  can 
  be 
  easily 
  and 
  certainly 
  determined, 
  we 
  may 
  take 
  it 
  as 
  a 
  

   measure 
  of 
  the 
  condition 
  of 
  the 
  air-space. 
  This 
  being 
  accepted, 
  and 
  

   general 
  diffusion 
  being 
  admitted, 
  we 
  can 
  easily 
  calculate 
  the 
  amount 
  of 
  

   fresh 
  air 
  required 
  to 
  bring 
  down 
  the 
  C0 
  2 
  to 
  some 
  fixed 
  standard, 
  adopt- 
  

   ing 
  as 
  a 
  datum 
  the 
  ascertained 
  average 
  amount 
  of 
  C0 
  2 
  evolved 
  by 
  an 
  adult 
  

   in 
  a 
  given 
  time. 
  If, 
  now, 
  we 
  adopt 
  as 
  our 
  standard 
  the 
  point 
  at 
  which 
  

   there 
  is 
  no 
  sensible 
  difference 
  between 
  the 
  air 
  of 
  an 
  inhabited 
  space 
  and 
  

   the 
  external 
  air, 
  and 
  agree 
  that 
  this 
  shall 
  be 
  determined 
  by 
  the 
  effects 
  on 
  

   the 
  sense 
  of 
  smell, 
  our 
  next 
  step 
  is 
  to 
  ascertain 
  from 
  experiment 
  what 
  is 
  

   the 
  average 
  amount 
  of 
  C0 
  2 
  in 
  such 
  an 
  air-space, 
  from 
  which 
  we 
  can 
  then 
  

   calculate 
  the 
  amount 
  of 
  air 
  required 
  to 
  keep 
  it 
  in 
  that 
  condition. 
  The 
  

   sense 
  of 
  smell 
  is 
  very 
  quickly 
  dulled, 
  so 
  that, 
  in 
  order 
  to 
  keep 
  it 
  acute, 
  

   each 
  air-space 
  to 
  be 
  examined 
  ought 
  to 
  be 
  entered 
  directly 
  from 
  the 
  open 
  

   air. 
  For 
  this 
  reason 
  I 
  have 
  not 
  included 
  in 
  the 
  present 
  paper 
  any 
  of 
  the 
  

   observations 
  made 
  in 
  prisons, 
  as 
  it 
  is 
  almost 
  impossible, 
  from 
  their 
  con- 
  

  

  