﻿ANIMAL 
  BEHAVIOUR 
  195 
  

  

  whole, 
  so 
  behaviour 
  differs 
  from 
  tropisms 
  in 
  being 
  an 
  effec- 
  

   tive 
  concatenation 
  or 
  correlation 
  of 
  successive 
  adjustments. 
  

   In 
  a 
  tropism 
  there 
  is 
  really 
  but 
  one 
  adjustment, 
  which 
  is 
  

   repeated 
  over 
  and 
  over 
  again. 
  In 
  behaviour 
  there 
  is 
  trial 
  

   after 
  trial 
  of 
  different 
  reactions, 
  and 
  a 
  selection 
  of 
  the 
  best 
  

   available 
  result. 
  

  

  7. 
  Non-intelligent 
  Experimentation. 
  

  

  Preoccupation 
  with 
  reflexes 
  and 
  tropisms 
  is 
  apt 
  to 
  lead 
  

   to 
  an 
  ignoring 
  of 
  the 
  ' 
  trial 
  movements 
  7 
  which 
  are 
  common 
  

   among 
  the 
  lower 
  animals. 
  " 
  Unprejudiced 
  observation 
  of 
  

   most 
  Invertebrates 
  will 
  show 
  that 
  they 
  perform 
  many 
  move- 
  

   ments 
  which 
  have 
  no 
  fixed 
  relation 
  to 
  sources 
  of 
  external 
  

   stimuli, 
  but 
  which 
  do 
  serve 
  to 
  test 
  the 
  surroundings 
  and 
  

   thus 
  to 
  guide 
  the 
  animal 
  ' 
  (Jennings, 
  p. 
  247). 
  Prof. 
  S. 
  J. 
  

   Holmes 
  writes 
  to 
  the 
  same 
  effect 
  and 
  gives 
  many 
  illustra- 
  

   tions 
  : 
  " 
  The 
  lives 
  of 
  most 
  insects, 
  crustaceans, 
  worms, 
  and 
  

   hosts 
  of 
  lower 
  Invertebrate 
  forms, 
  including 
  even 
  the 
  Pro- 
  

   tozoa, 
  show 
  an 
  amount 
  of 
  busy 
  exploration 
  that 
  in 
  many 
  

   cases 
  far 
  exceeds 
  that 
  made 
  by 
  any 
  higher 
  animal. 
  Through- 
  

   out 
  the 
  animal 
  kingdom 
  there 
  is 
  obedience 
  to 
  the 
  Pauline 
  

   injunction, 
  ( 
  Prove 
  all 
  things, 
  hold 
  fast 
  that 
  which 
  is 
  good 
  ; 
  

   (quoted 
  by 
  Jennings, 
  p. 
  250). 
  

  

  Among 
  simple 
  multicellular 
  animals 
  there 
  is, 
  one 
  must 
  

   admit, 
  not 
  a 
  little 
  of 
  that 
  restless 
  locomotion 
  which 
  we 
  see 
  

   in 
  Infusorians 
  and 
  the 
  like, 
  which 
  we 
  have 
  called 
  general 
  

   organismal 
  activity. 
  But 
  at 
  any 
  moment 
  this 
  may 
  give 
  

   place 
  to 
  more 
  definite 
  behaviour. 
  The 
  creature 
  commands 
  

   its 
  course 
  and 
  is 
  neither 
  blown 
  hither 
  and 
  thither 
  by 
  every 
  

   tropistic 
  gust 
  nor 
  bound 
  by 
  reflex 
  routine. 
  It 
  makes 
  sensori- 
  

   motor 
  experiments 
  which 
  work 
  towards 
  an 
  end, 
  such 
  as 
  the 
  

   systematic 
  exploration 
  of 
  a 
  corner 
  in 
  search 
  of 
  food. 
  It 
  

  

  