﻿138 
  W. 
  A. 
  LAMBORN. 
  

  

  and 
  the 
  bowl 
  containing 
  the 
  ova 
  was 
  then 
  placed 
  in 
  a 
  sunny 
  situation. 
  This 
  had 
  no 
  

   effect 
  either 
  ; 
  so 
  that, 
  unless 
  the 
  ova 
  were 
  unfertile, 
  their 
  removal 
  for 
  24-48 
  hours 
  

   at 
  a 
  very 
  early 
  stage 
  of 
  incubation, 
  and 
  their 
  drying 
  in 
  this 
  way, 
  must 
  have 
  resulted 
  

   in 
  their 
  death. 
  Unfortunately 
  no 
  control 
  ova 
  were 
  kept. 
  

  

  It 
  was 
  then 
  thought 
  possible 
  that 
  ova 
  might 
  retain 
  their 
  vitality 
  if 
  dried 
  under 
  

   more 
  natural 
  conditions 
  — 
  on 
  mud. 
  Accordingly, 
  on 
  25th 
  May, 
  63 
  ova, 
  laid 
  during 
  

   the 
  previous 
  night 
  by 
  an 
  A. 
  vagus, 
  were 
  transferred 
  at 
  10 
  a.m. 
  to 
  moist 
  mud, 
  which 
  

   was 
  then 
  placed 
  in 
  a 
  breeze 
  to 
  dry. 
  By 
  4 
  p.m. 
  all 
  the 
  ova 
  were 
  much 
  contorted 
  and 
  

   the 
  mud 
  was 
  apparently 
  dry. 
  After 
  an 
  interval 
  of 
  48 
  hours 
  water 
  was 
  graduaUy 
  

   added 
  so 
  that 
  the 
  ova 
  were 
  floated 
  off. 
  They 
  resumed 
  their 
  normal 
  form 
  in 
  the 
  course 
  

   of 
  the 
  next 
  24 
  hours, 
  but 
  none 
  hatched, 
  though 
  kept 
  under 
  observation 
  until 
  10th 
  

   June. 
  A 
  few 
  kept 
  on 
  water 
  as 
  a 
  control 
  hatched 
  in 
  due 
  course. 
  

  

  Ova 
  at 
  a 
  very 
  early 
  stage 
  of 
  incubation 
  being 
  apparently 
  unable 
  to 
  withstand 
  

   even 
  short 
  dessication, 
  experiments 
  were 
  set 
  on 
  foot 
  with 
  a 
  view 
  to 
  ascertaining 
  

   whether 
  ova 
  at 
  a 
  more 
  advanced 
  stage 
  were 
  more 
  resistant. 
  The 
  following 
  are 
  

   typical 
  experiments 
  of 
  this 
  nature 
  : 
  — 
  

  

  About 
  68 
  ova, 
  laid 
  two 
  nights 
  previously 
  by 
  an 
  A. 
  vagus, 
  were 
  removed 
  on 
  1st 
  

   June 
  at 
  8 
  a.m., 
  and 
  were 
  allowed 
  to 
  dry 
  in 
  the 
  laboratory. 
  Twenty-four 
  hours 
  later 
  

   25 
  of 
  these 
  were 
  transferred 
  to 
  water. 
  On 
  examination 
  a 
  day 
  later 
  three 
  larvae 
  

   were 
  found 
  to 
  have 
  hatched, 
  and 
  towards 
  the 
  end 
  of 
  the 
  morning 
  1 
  1 
  more 
  were 
  found. 
  

   One 
  larva 
  hatched 
  out 
  on 
  9th 
  June, 
  fully 
  24 
  hours 
  after 
  its 
  fellows. 
  The 
  rest 
  of 
  the 
  

   25 
  were 
  kept 
  under 
  observation 
  for 
  many 
  days 
  ; 
  all 
  failed 
  to 
  hatch. 
  The 
  balance 
  of 
  

   the 
  ova 
  removed, 
  totalling 
  43, 
  were 
  allowed 
  to 
  remain 
  in 
  a 
  dry 
  and 
  shrivelled 
  con- 
  

   dition 
  for 
  24 
  hours 
  still 
  longer, 
  till 
  9 
  a.m. 
  on 
  3rd 
  June, 
  when 
  they 
  were 
  restored 
  to 
  

   water. 
  Microscopical 
  examination 
  at 
  2 
  p.m. 
  showed 
  that 
  all 
  had 
  regained 
  their 
  shape, 
  

   and 
  after 
  24 
  hours 
  4 
  larvae 
  hatched 
  out. 
  Emergence 
  of 
  the 
  others 
  proceeded 
  

   so 
  rapidly 
  that 
  at 
  10 
  a.m. 
  there 
  were 
  19 
  larvae 
  and 
  at 
  11.40 
  a.m. 
  there 
  were 
  23 
  in 
  all. 
  

   The 
  rest 
  of 
  the 
  ova 
  failed 
  to 
  hatch. 
  

  

  Out 
  of 
  a 
  batch 
  of 
  138 
  eggs 
  laid 
  during 
  the 
  night 
  of 
  the 
  7th 
  June 
  by 
  an 
  A. 
  vagus, 
  

   having 
  been 
  on 
  the 
  water 
  about 
  36 
  hours, 
  103 
  were 
  removed 
  on 
  9th 
  at 
  11.30 
  a.m. 
  in 
  

   five 
  batches 
  and 
  were 
  kept 
  in 
  the 
  laboratory 
  to 
  dry. 
  Batch 
  (1), 
  consisting 
  of 
  9 
  

   ova, 
  was 
  restored 
  to 
  water 
  on 
  11th 
  June 
  at 
  2 
  p.m., 
  being 
  then, 
  as 
  the 
  result 
  of 
  

   desiccation 
  for 
  more 
  than 
  48 
  hours, 
  rather 
  flattened 
  though 
  fairly 
  full 
  in 
  appearance 
  ; 
  

   18 
  hours 
  later 
  2 
  larvae 
  had 
  hatched, 
  and 
  1 
  was 
  seen 
  at 
  8 
  a.m. 
  on 
  12th 
  June 
  in 
  the 
  

   act 
  of 
  emergence 
  from 
  the 
  eggshell 
  ; 
  four 
  hours 
  later 
  2 
  more 
  had 
  emerged. 
  On 
  13th 
  

   June, 
  at 
  10 
  a.m. 
  another 
  larva 
  hatched 
  out 
  ; 
  3 
  more 
  were 
  found 
  at 
  8 
  a.m. 
  on 
  15th, 
  

   evidently 
  having 
  just 
  hatched 
  out, 
  and 
  at 
  2 
  p.m. 
  on 
  that 
  day 
  still 
  another 
  came 
  out. 
  

   All 
  9 
  ova, 
  therefore, 
  which 
  must 
  have 
  been 
  in 
  an 
  advanced 
  state 
  of 
  incubation, 
  

   withstood 
  successfully 
  the 
  effects 
  of 
  desiccation 
  at 
  ordinary 
  laboratory 
  temperature 
  

   for 
  rather 
  over 
  48 
  hours, 
  the 
  larvae 
  emerging 
  between 
  12 
  and 
  84 
  hours 
  after 
  the 
  

   restoration 
  of 
  the 
  ova 
  to 
  water. 
  

  

  Batch 
  (2) 
  of 
  20 
  ova, 
  which 
  had 
  been 
  afforded 
  an 
  equal 
  period 
  of 
  time 
  for 
  incubation, 
  

   was 
  allowed 
  to 
  dry 
  for 
  24 
  hours 
  longer, 
  about 
  72 
  hours 
  in 
  all, 
  and 
  then 
  restored 
  to 
  

   water. 
  The 
  hatching 
  was 
  by 
  no 
  means 
  so 
  good, 
  for 
  9 
  only, 
  rather 
  less 
  than 
  50 
  per 
  

   cent., 
  emerged 
  within 
  a 
  period 
  of 
  24 
  hours, 
  between 
  8 
  a.m. 
  13th 
  and 
  8 
  a.m. 
  14th 
  

   June. 
  

  

  Batch 
  (3) 
  of 
  10 
  ova 
  was 
  allowed 
  to 
  dry 
  for 
  rather 
  over 
  96 
  hours, 
  batch 
  (4) 
  of 
  35 
  

   ova 
  was 
  allowed 
  to 
  dry 
  for 
  120 
  hours, 
  and 
  batch 
  (5) 
  of 
  29 
  ova 
  for 
  144 
  hours, 
  being 
  

   then 
  each 
  restored 
  to 
  water. 
  No 
  hatchings 
  at 
  all 
  took 
  place, 
  though 
  the 
  eggs, 
  which 
  

   were 
  mere 
  flattened 
  scales, 
  duly 
  filled 
  out 
  again. 
  The 
  control 
  batch 
  of 
  35 
  ova 
  hatched 
  

   out.* 
  

  

  * 
  The 
  awkward, 
  varying 
  and 
  apparently 
  arbitrary 
  numbers 
  employed 
  in 
  these 
  experiments 
  

   are 
  accounted 
  for 
  by 
  the 
  extreme 
  difficulty 
  of 
  separating 
  batches 
  of 
  tiny 
  eggs. 
  

  

  