This  particular  branch  of  natural  history  has  been
until  lately  but  indifferently  studied — in  fact,  considered
unworthy  of  higher  attention  than  that  which  could  be
bestowed  upon  it  by  schoolboys.  People  have  been  content
to  know  that  the  wonderful  architecture  and  mechanism
of  a  bird's  nest  was  the  outcome  of  a  force  vaguely  known
as  instinct,  without  taking  the  trouble  to  discover  its
workings,  extent,  or  limits.
6  SGQS   AND    EGG-COLLECTINQ.
Instinct  is  an  extremely  difficult  power  to  define,  and
whether  it  be  described  as  <{  hereditary  habit/'  or  simply
accepted  as  an  unknown  law  of  Nature  blindly  followed
by  its  possessor,  it  cannot  be  denied  that  it  is  the  outcome
of  conditions,  and  always  amenable  to  them.  If  the  word
mystery  were  tof ten  ^substituted  for  instinct,  it  would  not
belat'all  ouilo£  placevfor  it  means  quite  as  much.  It  is
\n£or£i  VdngsVtQ  acknowledge  our  ignorance  than  to  fence  it
round 'by 'specula^v^'-tiiebry  or  cover  it  by  almost  mean-
ingless phrases.  Survival  of  the  fittest  is  undoubtedly
Nature's  great  law.  With  this  end  in  view  she  governs
and  regulates  the  actions  of  birds  in  exactly  the  same  way
as  she  controls  the  colour  and  character  of  their  plumage,
shape,  size,  tint,  and  number  of  their  eggs,  first  move-
ments of  their  young,  and  other  peculiarities  we  do  not
understand.
