﻿MANUAL 
  OF 
  FISH-CULTURE. 
  17 
  

  

  is 
  a 
  decided 
  loss 
  of 
  fertilizing 
  power. 
  The 
  eggs 
  do 
  iiokt 
  suffer 
  so 
  (jiiickly 
  

   from 
  immersion 
  in 
  water. 
  The 
  absorbing 
  property 
  which 
  they 
  possess 
  

   when 
  they 
  first 
  leave 
  the 
  parent 
  fish, 
  and 
  which 
  attracts 
  to 
  tlie 
  

   micropyle 
  the 
  spermatozoa, 
  lasts 
  several 
  minutes, 
  but 
  it 
  is 
  not 
  prudent 
  

   to 
  leave 
  the 
  eggs 
  iu 
  the 
  water 
  a 
  moment 
  longer 
  than 
  is 
  necessary 
  before 
  

   adding 
  the 
  milt. 
  

  

  The 
  addition 
  of 
  the 
  water 
  is 
  not 
  essential 
  to 
  a 
  good 
  impregnation; 
  

   iu 
  some 
  instances 
  better 
  results 
  are 
  secured 
  without 
  the 
  use 
  of 
  water 
  

   and, 
  after 
  all, 
  if 
  the 
  main 
  object 
  is 
  secured, 
  of 
  bringing 
  the 
  milt 
  and 
  

   the 
  eggs 
  together 
  with 
  the 
  slightest 
  possible 
  delay 
  after 
  they 
  leave 
  the 
  

   fish, 
  it 
  makes 
  very 
  little 
  difference 
  whetber 
  water 
  is 
  used 
  or 
  not. 
  

   The 
  milt 
  retains 
  its 
  fertilizing 
  power 
  several 
  days 
  when 
  kept 
  from 
  air 
  

   and 
  water, 
  and 
  impregnation 
  can 
  be 
  effected 
  between 
  fishes 
  widely 
  

   separated 
  by 
  merely 
  forwarding 
  the 
  milt 
  properly 
  sealed. 
  At 
  Baird 
  

   impregnation 
  by 
  tlie 
  dr}' 
  method, 
  which 
  has 
  always 
  been 
  followed 
  there, 
  

   has 
  resulted 
  m 
  the 
  fertilization 
  of 
  about 
  90 
  per 
  cent 
  of 
  the 
  eggs 
  so 
  treated. 
  

  

  The 
  Russian 
  or 
  dry 
  method 
  of 
  impregnating 
  eggs 
  consists 
  simply 
  in 
  

   taking 
  both 
  the 
  eggs 
  and 
  the 
  milt 
  in 
  a 
  dry 
  pan. 
  It 
  may 
  be 
  urged 
  as 
  

   an 
  objection 
  to 
  this 
  method 
  that 
  the 
  eggs 
  will 
  be 
  injured 
  by 
  striking 
  

   against 
  the 
  dry 
  pan, 
  but 
  it 
  is 
  a 
  fact 
  that 
  although 
  the 
  same 
  eggs 
  would 
  

   be 
  destroyed 
  by 
  the 
  concussion 
  a 
  week 
  afterwards, 
  or 
  even 
  twenty-four 
  

   hours 
  afterwards, 
  they 
  do 
  not 
  suffer 
  in 
  the 
  least 
  from 
  it 
  at 
  the 
  moment 
  

   of 
  extrusion 
  from 
  the 
  fish. 
  

  

  It 
  was 
  at 
  one 
  time 
  considered 
  an 
  important 
  question 
  whether 
  the 
  

   eggs 
  or 
  milt 
  sliould 
  be 
  taken 
  first, 
  but 
  with 
  the 
  dry 
  method 
  it 
  makes 
  

   no 
  difference, 
  as, 
  either 
  way, 
  both 
  eggs 
  and 
  milt 
  remain 
  operative 
  long 
  

   enough 
  for 
  all 
  practical 
  purposes 
  of 
  impregnation. 
  

  

  Various 
  methods 
  of 
  treating 
  the 
  eggs 
  in 
  the 
  pan 
  after 
  impregnation 
  

   has 
  taken 
  place 
  have 
  been 
  tried, 
  and 
  all 
  apparently 
  with 
  about 
  the 
  

   same 
  results. 
  Some 
  operators 
  leave 
  the 
  eggs 
  in 
  the 
  pans 
  as 
  first 
  taken 
  

   with 
  the 
  milt 
  for 
  two 
  or 
  three 
  minutes 
  and 
  then 
  add 
  water, 
  after 
  which 
  

   they 
  are 
  left 
  to 
  stand 
  in 
  the 
  pan 
  until 
  they 
  separate, 
  when 
  they 
  are 
  

   washed 
  clean, 
  taken 
  to 
  the 
  hatching-house, 
  and 
  placed 
  in 
  the 
  troughs. 
  

   Others 
  pour 
  the 
  contents 
  of 
  the 
  several 
  pans 
  — 
  eggs, 
  milt, 
  and 
  all 
  — 
  into 
  

   a 
  large 
  can, 
  after 
  they 
  have 
  remained 
  in 
  the 
  pans 
  just 
  long 
  enough 
  to 
  

   become 
  impregnated. 
  When 
  the 
  eggs 
  separate 
  the 
  contents 
  of 
  the 
  can 
  

   are 
  poured 
  into 
  the 
  hatching- 
  troughs 
  just 
  as 
  they 
  are, 
  trus<ting 
  to 
  the 
  

   current 
  in 
  the 
  troughs 
  to 
  wash 
  the 
  milt 
  from 
  the 
  eggs. 
  Where 
  the 
  

   water 
  supply 
  is 
  scant 
  and 
  the 
  current 
  sluggish 
  in 
  the 
  trays, 
  the 
  best 
  

   method 
  is 
  to 
  wash 
  the 
  milt 
  thoroughly 
  from 
  the 
  eggs 
  before 
  placing 
  

   them 
  in 
  the 
  hatching-trays, 
  as 
  the 
  milt 
  will 
  foul 
  the 
  water 
  if 
  it 
  remains 
  

   in 
  the 
  troughs. 
  

  

  The 
  methods 
  employed 
  in 
  taking 
  and 
  fertilizing 
  eggs 
  at 
  Clackamas 
  

   station 
  are 
  as 
  follows 
  : 
  The 
  female 
  fish 
  to 
  be 
  operated 
  upon 
  is 
  taken 
  

   from 
  a 
  floating 
  pen 
  and 
  placed 
  iu 
  the 
  spawning-box 
  or 
  "straight- 
  

   jacket"; 
  a 
  male 
  fish 
  is 
  then 
  caught 
  and 
  tied 
  with 
  a 
  small 
  rope 
  aBOund 
  

  

  p. 
  C. 
  R. 
  1897 
  2 
  

  

  