﻿MYSTERY 
  OF 
  LIFE 
  DONNAN 
  311 
  

  

  activity. 
  A 
  steam 
  engine 
  moves 
  and 
  does 
  work 
  because 
  the 
  coal 
  and 
  

   oxygen 
  are 
  not 
  in 
  equilibrium, 
  just 
  as 
  an 
  animal 
  lives 
  and 
  acts 
  be- 
  

   cause 
  its 
  food 
  and 
  oxygen 
  are 
  not 
  in 
  equilibrium. 
  As 
  Bayliss 
  has 
  so 
  

   finely 
  put 
  it, 
  equilibrium 
  is 
  death. 
  The 
  chief 
  source 
  of 
  life 
  and 
  

   activity 
  on 
  this 
  planet 
  arises 
  from 
  the 
  fact 
  that 
  the 
  cool 
  surface 
  of 
  the 
  ' 
  

   earth 
  is 
  constantly 
  bathed 
  in 
  a 
  flood 
  of 
  high-temperature 
  light. 
  If 
  

   radiation 
  in 
  thermal 
  equilibrium 
  with 
  the 
  average 
  temperature 
  of 
  the 
  

   earth's 
  crust 
  were 
  the 
  only 
  radiant 
  energy 
  present, 
  practically 
  all 
  life 
  

   as 
  we 
  know 
  it 
  would 
  cease, 
  for 
  then 
  the 
  chlorophyll 
  of 
  the 
  green 
  plants 
  

   would 
  cease 
  to 
  assimilate 
  carbonic 
  acid 
  and 
  convert 
  it 
  into 
  sugar 
  and 
  

   starch. 
  The 
  photochemical 
  assimilation 
  of 
  the 
  green 
  plant 
  is 
  a 
  fact 
  of 
  

   supreme 
  importance 
  in 
  the 
  economy 
  of 
  life. 
  This 
  transformation 
  of 
  

   carbonic 
  acid 
  and 
  water 
  into 
  starch 
  and 
  oxygen 
  represents 
  an 
  increase 
  

   of 
  free 
  energy, 
  since 
  the 
  starch 
  and 
  oxygen 
  tend 
  naturally 
  to 
  react 
  

   together 
  and 
  give 
  carbonic 
  acid 
  and 
  water. 
  Such 
  an 
  increase 
  in 
  free 
  

   energy 
  would 
  be 
  impossible 
  if 
  there 
  existed 
  no 
  compensating 
  running 
  

   down 
  or 
  degradation 
  of 
  energy. 
  But 
  this 
  running 
  down 
  or 
  fall 
  in 
  

   potential 
  is 
  provided 
  by 
  the 
  difference 
  in 
  temperature 
  between 
  the 
  

   surface 
  of 
  the 
  sun 
  and 
  the 
  surface 
  of 
  the 
  earth, 
  a 
  difference 
  of 
  some 
  

   five 
  or 
  six 
  thousand 
  degrees. 
  All 
  living 
  things 
  live 
  and 
  act 
  by 
  utilizing 
  

   some 
  form 
  of 
  nonequUibrium 
  or 
  free 
  energy 
  in 
  their 
  environment. 
  

   The 
  living 
  cell 
  acts 
  as 
  an 
  energy 
  transformer, 
  running 
  some 
  of 
  the 
  free 
  

   energy 
  of 
  its 
  environment 
  down 
  to 
  a 
  lower 
  level 
  of 
  potential 
  and 
  

   simultaneously 
  building 
  some 
  up 
  to 
  a 
  higher 
  level 
  of 
  potential. 
  The 
  

   nitrifying 
  bacteria 
  investigated 
  by 
  Winogradsky 
  and 
  recently 
  by 
  

   Meyerhof 
  utilize 
  the 
  free 
  energy 
  of 
  ammonia 
  plus 
  oxygen. 
  By 
  

   burning 
  the 
  ammonia 
  to 
  nitrous 
  or 
  nitric 
  acid 
  they 
  are 
  enabled 
  to 
  

   assimilate 
  carbonic 
  acid 
  and 
  convert 
  it 
  into 
  sugar 
  or 
  protein. 
  Other 
  

   bacteria 
  utilize 
  the 
  free 
  energy 
  of 
  sulphuretted 
  hydrogen 
  plus 
  oxygen. 
  

   Fungi 
  and 
  anaerobic 
  bacteria 
  utilize 
  the 
  free 
  energy 
  available 
  when 
  

   complex 
  organic 
  compounds 
  pass 
  into 
  simpler 
  chemical 
  compounds. 
  

   The 
  close 
  study 
  of 
  these 
  energy 
  exchanges 
  and 
  transformations 
  is 
  

   becoming 
  a 
  very 
  important 
  branch 
  of 
  cellular 
  physiology, 
  and 
  in 
  the 
  

   hands 
  of 
  Warburg 
  and 
  Meyerhof 
  in 
  Germany 
  and 
  of 
  A. 
  V. 
  Hill 
  in 
  

   England 
  — 
  to 
  mention 
  only 
  a 
  few 
  eminent 
  names 
  — 
  has 
  already 
  yielded 
  

   results 
  of 
  the 
  greatest 
  value 
  and 
  importance. 
  It 
  would 
  be 
  a 
  great 
  

   thing 
  if 
  one 
  of 
  these 
  investigators 
  were 
  to 
  find 
  a 
  case 
  where 
  the 
  second 
  

   law 
  of 
  thermodynamics 
  broke 
  down. 
  Up 
  to 
  the 
  present, 
  however, 
  it 
  

   appears 
  that 
  all 
  these 
  energy 
  transformations 
  of 
  the 
  living 
  cell 
  conform 
  

   with 
  the 
  second 
  law 
  as 
  it 
  applies 
  to 
  the 
  inanimate 
  world. 
  Thus 
  

   another 
  part 
  of 
  the 
  apparent 
  freedom 
  or 
  spontaneity 
  of 
  life, 
  of 
  which 
  

   I 
  spoke 
  before, 
  disappears. 
  A 
  living 
  being 
  is 
  not 
  a 
  magical 
  source 
  of 
  

   free 
  energy 
  or 
  spontaneous 
  action. 
  Its 
  life 
  and 
  activity 
  are 
  ruled 
  and 
  

   controlled 
  by 
  the 
  amount 
  and 
  nature 
  of 
  the 
  free 
  energy, 
  the 
  physical 
  

   or 
  chemical 
  nonequilibrium, 
  in 
  its 
  immediate 
  environment, 
  and 
  it 
  

  

  