﻿RELATION 
  OF 
  TEMPERATURE 
  TO 
  DEVELOPMENT 
  OF 
  THE 
  EGGS. 
  137 
  

  

  lem 
  under 
  discussion. 
  That 
  it 
  serves 
  to 
  bring 
  to 
  view 
  an 
  important 
  

   factor 
  that 
  had 
  not 
  been 
  sufficiently 
  considered 
  is 
  undoubtedly 
  true; 
  it 
  

   also 
  clearly 
  indicates, 
  so 
  to 
  speak, 
  an 
  inner 
  law 
  of 
  the 
  influence 
  of 
  heat 
  

  

  Eeferring 
  the 
  reader 
  to 
  our 
  First 
  Report 
  for 
  an 
  explanation 
  and 
  illus- 
  

   stration 
  of 
  the 
  theory 
  as 
  given 
  by 
  Professor 
  Abbe, 
  we 
  propose 
  to 
  discuss 
  

   it 
  briefly 
  here. 
  

  

  That 
  there 
  is 
  a 
  limiting 
  temperature 
  below 
  which, 
  if 
  continuous, 
  the 
  

   eggs 
  will 
  not 
  hatch 
  must 
  be 
  admitted. 
  Just 
  what 
  that 
  limit 
  is 
  has 
  not 
  

   yet 
  been 
  accurately 
  determined, 
  though 
  approximately 
  reached 
  by 
  the 
  

   experiments 
  made 
  by 
  Mr. 
  Riley 
  in 
  1876-'77. 
  

  

  But 
  in-door 
  experiments, 
  although 
  conducted 
  with 
  the 
  utmost 
  skill 
  

   and 
  precision, 
  are 
  likely 
  to 
  vary 
  more 
  or 
  less, 
  in 
  their 
  results, 
  from 
  what 
  

   will 
  be 
  found 
  to 
  be 
  true 
  in 
  the 
  actual 
  out 
  -door 
  life 
  of 
  the 
  species 
  ; 
  still 
  

   they 
  form 
  a 
  good 
  basis 
  upon 
  which 
  to 
  work, 
  and 
  serve 
  as 
  an 
  excellent 
  

   guide 
  to 
  the 
  fact 
  sought 
  for. 
  

  

  Professor 
  Abbe 
  assumes 
  the 
  following 
  as 
  a 
  "working 
  hypothesis:" 
  207 
  

   that, 
  at 
  a 
  uniform 
  temperature 
  of 
  50° 
  Fahr. 
  the 
  eggs 
  require 
  65 
  whole 
  

   days, 
  or 
  1,560 
  hours, 
  to 
  hatch. 
  

  

  At 
  a 
  uniform 
  temperature 
  of 
  60°, 
  they 
  require 
  60 
  whole 
  days, 
  or 
  

   1.440 
  hours, 
  to 
  hatch. 
  

  

  At 
  a 
  uniform 
  temperature 
  of 
  70°, 
  they 
  require 
  55 
  whole 
  days, 
  or 
  1,320 
  

   hours, 
  to 
  hatch. 
  

  

  It 
  is 
  proper 
  to 
  call 
  attention 
  in 
  this 
  connection 
  to 
  note 
  94, 
  on 
  page 
  428 
  

   of 
  our 
  First 
  Report, 
  but 
  the 
  object 
  we 
  now 
  have 
  in 
  view 
  does 
  not 
  re- 
  

   quire 
  any 
  explanation 
  of 
  the 
  difference 
  there 
  alluded 
  to. 
  

  

  That 
  eggs 
  have 
  repeatedly 
  hatched 
  in 
  some 
  of 
  the 
  northern 
  sections 
  

   when 
  the 
  maximum 
  temperature 
  had 
  not 
  at 
  any 
  time 
  during 
  the 
  spring 
  

   exceeded 
  52° 
  or 
  53°, 
  and 
  seldom 
  rose 
  to 
  50°, 
  is 
  evident 
  from 
  data 
  

   obtained 
  by 
  the 
  Commission. 
  We 
  may 
  therefore 
  safely 
  assume 
  that 
  a 
  

   temperature 
  of 
  50° 
  is 
  not 
  below 
  the 
  hatching 
  point. 
  We 
  may 
  also 
  as- 
  

   sume 
  as 
  borne 
  out 
  by 
  the 
  facts 
  that 
  eggs 
  deposited 
  early 
  in 
  the 
  season 
  

   will, 
  as 
  a 
  rule, 
  hatch 
  out, 
  under 
  the 
  same 
  conditions, 
  earlier 
  the 
  next 
  

   spring 
  than 
  those 
  deposited 
  later. 
  Mr. 
  Stolley, 
  of 
  Hall 
  County, 
  Ne- 
  

   braska, 
  who 
  is 
  in 
  the 
  habit 
  of 
  observing 
  and 
  recording 
  the 
  dates 
  of 
  

   depositing 
  and 
  hatching, 
  had 
  already 
  noticed 
  this 
  fact, 
  and 
  so 
  informed 
  

   us 
  in 
  1877. 
  Professor 
  Whitman 
  and 
  others 
  have 
  also 
  observed 
  the 
  same 
  

   thing. 
  It 
  appears, 
  therefore, 
  that 
  the 
  process 
  of 
  forming 
  the 
  embryo 
  

   commences 
  in 
  the 
  fall, 
  and 
  that 
  the 
  sum 
  of 
  the 
  heat 
  above 
  a 
  certain 
  

   degree 
  is 
  a 
  factor 
  not 
  to 
  be 
  overlooked 
  ; 
  and 
  we 
  may 
  remark 
  here, 
  as 
  

   indicated 
  by 
  what 
  has 
  been 
  shown 
  in 
  this 
  chapter, 
  that 
  the 
  sum 
  of 
  the 
  

   cold 
  below 
  a 
  certain 
  degree 
  also 
  appears 
  to 
  be 
  an 
  important 
  factor 
  in 
  

   the 
  problem. 
  

  

  As 
  Mr. 
  Stolley 
  gives 
  us 
  the 
  exact 
  date 
  at 
  which 
  eggs 
  were 
  first 
  de- 
  

   posited 
  in 
  Hall 
  County 
  in 
  1877, 
  let 
  us 
  try 
  Professor 
  Abbe's 
  "working 
  

   basis" 
  and 
  theory 
  by 
  an 
  examination 
  of 
  this 
  case. 
  It 
  is 
  true 
  we 
  have 
  

   no 
  meteorological 
  record 
  for 
  that 
  immediate 
  section, 
  but 
  as 
  Omaha 
  and 
  

  

  First 
  Report, 
  page 
  428. 
  

  

  