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  ORGANISM 
  AND 
  MECHANISM 
  

  

  seems 
  to 
  be 
  with 
  the 
  conservation 
  of 
  energy. 
  An 
  animal, 
  

   such 
  as 
  a 
  dog, 
  supposed 
  for 
  the 
  sake 
  of 
  simplicity 
  to 
  be 
  at 
  

   rest, 
  takes 
  in 
  potential 
  energy 
  in 
  the 
  form 
  of 
  food, 
  and 
  takes 
  

   in 
  oxygen 
  to 
  keep 
  the 
  vital 
  combustion 
  agoing. 
  It 
  uses 
  up 
  

   the 
  energy 
  in 
  internal 
  activities: 
  the 
  heart 
  drives 
  the 
  blood 
  

   round 
  the 
  body, 
  the 
  midriff 
  rises 
  and 
  falls, 
  the 
  lungs 
  empty 
  

   and 
  fill, 
  and 
  so 
  on. 
  Now, 
  if 
  we 
  allow 
  for 
  the 
  potential 
  

   energy 
  of 
  waste-products 
  and 
  storage-products, 
  we 
  find 
  that 
  

   the 
  heat 
  given 
  off 
  is 
  in 
  accurate 
  correspondence 
  with 
  the 
  

   energy 
  taken 
  in. 
  The 
  accounts 
  balance. 
  The 
  invention 
  

   known 
  as 
  a 
  calorimeter 
  made 
  it 
  possible 
  for 
  Rubner 
  to 
  dem- 
  

   onstrate 
  that 
  the 
  heat-energy 
  given 
  off 
  by 
  an 
  animal 
  during 
  

   a 
  prolonged 
  experiment 
  was 
  the 
  equivalent 
  of 
  the 
  food 
  taken 
  

   in, 
  with 
  a 
  discrepancy 
  of 
  only 
  0.5 
  per 
  cent., 
  which 
  is 
  believed 
  

   to 
  be 
  the 
  all 
  but 
  inevitable 
  discrepancy 
  due 
  to 
  the 
  conditions 
  

   of 
  experiment. 
  There 
  was 
  a 
  smaller 
  discrepancy 
  (0.1 
  per 
  

   cent.) 
  in 
  Atwater's 
  experiment 
  of 
  sixty-six 
  days 
  during 
  

   which 
  his 
  students 
  worked 
  in 
  a 
  calorimeter. 
  When 
  they 
  re- 
  

   mained 
  at 
  rest, 
  the 
  discrepancy 
  disappeared. 
  It 
  is 
  plain, 
  

   then, 
  that 
  the 
  living 
  of 
  the 
  animal 
  is 
  in 
  general 
  accordance 
  

   with 
  the 
  big 
  generalisation 
  that 
  the 
  sum 
  total 
  of 
  energy 
  

   in 
  a 
  closed 
  system 
  remains 
  constant. 
  One 
  mode 
  may 
  change 
  

   into 
  another 
  mode, 
  but 
  no 
  energy 
  ceases 
  or 
  is 
  lost 
  in 
  the 
  

   transformation. 
  

  

  It 
  is 
  certain 
  that 
  a 
  chemical 
  and 
  physical 
  description 
  

   can 
  be 
  given 
  of 
  much 
  that 
  goes 
  on 
  in 
  organisms, 
  and 
  this 
  

   kind 
  of 
  description 
  will 
  certainly 
  extend 
  its 
  scope. 
  We 
  need 
  

   only 
  refer 
  to 
  Professor 
  Bayliss's 
  Principles 
  of 
  Physiology 
  

   as 
  a 
  fine 
  illustration 
  of 
  the 
  application 
  of 
  chemical 
  and 
  

   physical 
  analysis 
  to 
  the 
  activities 
  of 
  the 
  living 
  body, 
  and 
  to 
  

   Professor 
  D'Arcy 
  Thompson's 
  Growth 
  and 
  Form 
  as 
  its 
  

   counterpart 
  in 
  the 
  domain 
  of 
  morphology. 
  At 
  the 
  same 
  time 
  

  

  