158 
Our  Canaries 
desire  to  sit  in  it,  and  start  incubation  at  once.  The  incubation  stage  is 
normally  broken  by  the  hatching  of  the  chicks,  and  their  movements  beneath 
the  hen  are  probably  the  stimulus  to  her  to  begin  the  feeding  stage.  The 
sitting  on  addled  eggs  can  be,  and  is  sometimes,  prolonged  for  six  weeks,  and  it 
seems  feasible  to  suggest  the  absence  of  the  movements  of  the  chicks  as  the 
cause  of  its  undue  prolongation." 
STILLNESS  BEGETS  PATIENCE. 
"  In  squatting  hens  this  absence  of  movement  may  be  the  cause  of  the 
hen's  patience.  If  eggs  have  been  put  under  a  hen  that  has  been  squatting 
or  sitting  on  eggs  for  some  prolonged  period,  it  seems  probable  that  a  habit  has 
been  acquired  which  not  even  the  movements  of  the  chicks  is  strong  enough 
to  break.  The  hen  does  not  rise  and  has  no  stimulus  to  feed,  with  the 
result  that  the  young  are  crushed  or  starved. 
"  By  the  time  the  feeding  stage  is  nearing  completion,  and  the  young  are 
able,  in  part  at  least,  to  look  after  themselves,  another  batch  of  ovules  is  on 
the  way  to  maturity,  and  the  reproductive  cycle  is  again  about  to  be  repeated. 
It  will  thus  be  seen  that  many  and  varied  factors  may  cause  a  deviation  from 
the  normal  reproductive  cycle." 
CONCLUSIONS  ARRIVED  AT. 
"  Having  outlined  normal  and  abnormal  cycles,  some  attempts  may  now 
be  made  to  suggest  explanations  for  the  instances  previously  quoted. 
"No.  I.  Ovules  not  sufficiently  mature.  Stimulus  from  pairing  up  suffi- 
cient to  start  instinct  to  build,  but  not  to  complete  the  process,  and  not 
sufficient  to  lead  to  incubation  until  time  elapsed  for  further  maturation  of 
the  ovules. 
"No.  2.  Ovules  again  immature.  Stimulus  sufficient  to  start  cycle  and 
incubation,  although  no  eggs  laid.  By  time  pan  removed,  ovules  sufficiently 
advanced  for  a  natural  cycle  to  be  started,  and  successfully  carried  out. 
"No.  3.  Impulse  to  lay  at  normal  time.  Maturation  retarded  by  absence 
of  receptacle,  material,  and  the  cock,  and  therefore  no  nest  or  eggs.  Cycle 
continued  and  incubation  stage  induced.  Cycle  broken  by  change  of  cage, 
and  presence  of  cock  precipitates  maturation  to  such  an  extent  that  no  time 
for  selection  of  nesting  place,  and  no  nest  built  from  previous  denial  of 
material.  The  cock  being  very  vigorous,  the  usual  few  days'  chasing  and 
driving  about  of  the  hen  also  prevented  her  having  opportunities  for  nest  place 
selection," 
LATE  DEVELOPMENT. 
"  No.  4.  Probably  reproductive  system  lying  dormant  for  the  first  year, 
or  insufficiently  developed. 
"  No.  5.  Incubation  continued  from  lack  of  movement  of  chicks.  Eggs 
not  necessary  for  continuance  of  this  prolonged  incubation  process.    If  a  hen 
