﻿THE 
  ELEMENT 
  OF 
  COLOUR. 
  103 
  

  

  produce 
  upon 
  Mankind 
  some 
  modifications 
  of 
  

   colour, 
  and 
  of 
  features. 
  But 
  we 
  know 
  also 
  

   that 
  such 
  changes 
  are 
  extremely 
  slow. 
  

   Colour 
  is 
  in 
  all 
  the 
  lower 
  animals 
  one 
  of 
  

   the 
  least 
  constant 
  — 
  that 
  is 
  to 
  say, 
  one 
  of 
  

   the 
  most 
  variable, 
  — 
  of 
  external 
  characters 
  ; 
  

   and 
  under 
  circumstances 
  of 
  domestication 
  

   changes 
  of 
  colour 
  are 
  sometimes 
  sudden, 
  

   and 
  are 
  connected 
  with 
  causes 
  altogether 
  

   unknown. 
  But 
  we 
  have 
  no 
  evidence 
  to 
  

   show 
  that 
  human 
  colour 
  is 
  liable 
  to 
  changes 
  

   of 
  a 
  like 
  kind. 
  On 
  the 
  contrary, 
  all 
  ex- 
  

   perience 
  seems 
  to 
  point 
  to 
  the 
  conclusion 
  

   that 
  varieties 
  of 
  complexion 
  can 
  only 
  be 
  

   established 
  very 
  gradually, 
  and 
  we 
  have 
  no 
  

   absolute 
  proof 
  that 
  a 
  change 
  from 
  white 
  

   to 
  negro 
  blackness 
  is 
  possible 
  at 
  all. 
  A 
  

  

  