﻿THE 
  CRITERIA 
  OF 
  LIVINGNESS 
  91 
  

  

  the 
  duration 
  of 
  individual 
  life 
  at 
  the 
  one 
  extreme. 
  The 
  

   Big 
  Trees 
  living 
  for 
  two 
  thousand 
  years 
  may 
  be 
  near 
  the 
  

   limit 
  in 
  the 
  other 
  direction. 
  

  

  4. 
  The 
  Capacity 
  of 
  Growth, 
  Reproduction, 
  and 
  

  

  Development. 
  

  

  One 
  can 
  readily 
  conceive 
  of 
  an 
  organism 
  which 
  balanced 
  

   its 
  accounts 
  from 
  hour 
  to 
  hour, 
  but 
  never 
  had 
  much 
  margin. 
  

   There 
  are 
  such 
  delicately-poised 
  ephemeral 
  organisms, 
  which 
  

   live, 
  to 
  use 
  a 
  homely 
  expression, 
  from 
  hand 
  to 
  mouth. 
  They 
  

   are 
  going 
  concerns, 
  but 
  they 
  are 
  trading 
  on 
  a 
  very 
  restricted 
  

   capital, 
  and 
  cannot 
  survive 
  a 
  crisis. 
  So 
  we 
  see 
  at 
  once 
  that 
  

   there 
  is 
  a 
  commanding 
  advantage 
  in 
  being 
  able 
  to 
  store 
  energy 
  

   in 
  potential 
  form, 
  and 
  this 
  is 
  fundamentally 
  characteristic 
  

   of 
  organisms 
  especially 
  of 
  plants. 
  As 
  regards 
  the 
  ratio 
  

   between 
  the 
  income 
  of 
  energy 
  and 
  the 
  work 
  done, 
  living 
  

   organisms 
  are 
  far 
  ahead 
  of 
  any 
  engine, 
  but 
  there 
  is 
  also 
  

   the 
  power 
  of 
  accumulating 
  energy 
  which 
  can 
  be 
  used 
  later. 
  

   Thus 
  we 
  are 
  led 
  to 
  recognise 
  the 
  po~wer 
  of 
  growth 
  as 
  one 
  

   of 
  the 
  characteristics 
  of 
  organisms. 
  A 
  surplus 
  of 
  income 
  

   over 
  expenditure 
  is 
  the 
  primal, 
  condition 
  of 
  organic 
  growth. 
  

   It 
  has 
  further 
  to 
  be 
  noted 
  that 
  the 
  growth 
  of 
  living 
  creatures, 
  

   as 
  contrasted 
  with 
  that 
  of 
  crystals, 
  is 
  at 
  the 
  expense 
  of 
  

   materials 
  different 
  from 
  those 
  which 
  compose 
  the 
  organism; 
  

   it 
  implies 
  active 
  assimilation, 
  not 
  passive 
  accretion; 
  and 
  it 
  

   is 
  very 
  definitely 
  a 
  regulated 
  process. 
  An 
  organism 
  does 
  not 
  

   grow 
  like 
  a 
  snowball. 
  

  

  But 
  growth 
  leads 
  on 
  to 
  multiplication. 
  As 
  Haeckel 
  clearly 
  

   indicated 
  in 
  his 
  Generelle 
  Morphologie 
  (1866), 
  repro- 
  

   duction 
  is 
  discontinuous 
  growth. 
  How 
  impossible 
  it 
  is 
  to 
  

   draw 
  any 
  hard 
  and 
  fast 
  line 
  between 
  a 
  fragmentation 
  which 
  

   separates 
  off 
  overgrowths, 
  and 
  the 
  more 
  specialised 
  modes 
  

  

  