﻿FISHERY 
  INDUSTEIES. 
  87 
  

  

  organic 
  life 
  — 
  to 
  annihilate 
  the 
  minute 
  organisms 
  and 
  their 
  spores 
  

   which 
  inhabit 
  the 
  flesh 
  of 
  the 
  fish, 
  as 
  well 
  as 
  those 
  which 
  may 
  enter 
  

   during 
  the 
  process 
  of 
  packing 
  — 
  and 
  then 
  seal 
  tightly 
  in 
  a 
  container 
  

   so 
  that 
  there 
  may 
  be 
  no 
  bacteriological 
  development 
  through 
  the 
  

   admission 
  of 
  air. 
  

  

  A 
  leak 
  in 
  the 
  container 
  will 
  result 
  usually 
  in 
  the 
  formation 
  of 
  gases 
  

   that 
  will 
  cause 
  pronounced 
  distension 
  of 
  the 
  ends, 
  and 
  it 
  has 
  come 
  

   to 
  be 
  generally 
  recognized 
  that 
  a 
  swelled 
  or 
  bulged 
  end 
  is 
  diagnostic 
  

   of 
  spoiled 
  contents. 
  This 
  is 
  a 
  proper 
  criterion 
  for 
  casual 
  and 
  external 
  

   determination 
  of 
  quality, 
  though 
  it 
  does 
  not 
  always 
  follow 
  that 
  a 
  

   slightly 
  distended 
  end 
  necessarily 
  means 
  a 
  spoiled 
  can. 
  It 
  some- 
  

   times 
  happens 
  that 
  a 
  perfectly 
  good 
  can 
  of 
  salmon 
  may, 
  in 
  the 
  course 
  

   of 
  its 
  long 
  journey 
  from 
  the 
  cannery 
  to 
  the 
  retailer's 
  shelf, 
  receive 
  

   jars 
  and 
  jolts 
  that 
  will 
  cause 
  the 
  ends 
  to 
  bulge 
  in 
  a 
  most 
  suspicious 
  

   manner. 
  No 
  conscientious 
  salesman 
  thinks 
  of 
  offering 
  such 
  a 
  can 
  

   for 
  sale, 
  and 
  the 
  consequent 
  loss 
  eventually 
  falls 
  upon 
  the 
  packer. 
  

   The 
  obvious 
  preventive 
  remedy 
  is 
  the 
  creation 
  of 
  a 
  vacuum 
  within 
  the 
  

   can 
  to 
  ii)sure 
  a 
  continuously 
  collapsed 
  state 
  of 
  the 
  ends. 
  Thus 
  in 
  the 
  

   processing 
  of 
  salmon 
  there 
  are 
  two 
  distinct 
  steps, 
  the 
  first 
  being 
  that 
  

   of 
  securing 
  the 
  required 
  exhaust 
  or 
  vacuum, 
  and 
  second, 
  the 
  cooking 
  

   proper. 
  

  

  Under 
  the 
  old 
  method 
  of 
  canning 
  the 
  first 
  cooking, 
  which 
  takes 
  

   place 
  immediately 
  after 
  the 
  top 
  has 
  been 
  soldered 
  on 
  the 
  filled 
  can 
  and 
  

   central 
  vent 
  stopped 
  up, 
  is 
  known 
  as 
  the 
  exhausting 
  process. 
  After 
  

   the 
  contents 
  have 
  thus 
  been 
  well 
  heated, 
  the 
  top 
  is 
  punctured, 
  per- 
  

   mitting 
  the 
  expanded 
  air 
  and 
  the 
  gases 
  liberated 
  by 
  the 
  heat 
  to 
  escape 
  

   or 
  blow 
  off, 
  and 
  the 
  vent 
  thus 
  created 
  is 
  quickly 
  soldered 
  before 
  the 
  

   can 
  and 
  its 
  contents 
  can 
  cool 
  and 
  fill 
  up 
  with 
  air 
  again. 
  A 
  strong 
  

   vacuum 
  is 
  thus 
  secured, 
  as 
  the 
  excess 
  air 
  has 
  been 
  exhausted. 
  This 
  

   involves 
  an 
  expenditure 
  of 
  considerable 
  time 
  and 
  labor, 
  some 
  Httle 
  

   fuel 
  and 
  other 
  materials, 
  and 
  the 
  employment 
  of 
  certain 
  machinery, 
  

   much 
  of 
  which 
  is 
  done 
  away 
  with 
  by 
  the 
  modern 
  sanitary 
  system 
  of 
  

   exhausting. 
  

  

  As 
  a 
  modification 
  of 
  the 
  old 
  method, 
  a 
  practice 
  came 
  into 
  vogue 
  in 
  

   which 
  the 
  filled 
  can, 
  after 
  having 
  the 
  top 
  soldered 
  on, 
  was 
  given 
  its 
  

   exhaust 
  heat 
  with 
  the 
  central 
  vent 
  open, 
  the 
  small 
  aperture 
  being 
  

   stopped 
  with 
  solder 
  after 
  the 
  exhausting 
  was 
  regarded 
  as 
  ended. 
  

   This 
  was 
  accomplished 
  either 
  by 
  use 
  of 
  the 
  old 
  style 
  of 
  cannery 
  equip- 
  

   ment 
  in 
  which 
  the 
  filled 
  cans 
  with 
  this 
  vent 
  were 
  given 
  the 
  exhaust 
  

   heat 
  in 
  the 
  same 
  sort 
  of 
  cooking 
  cylinders 
  or 
  retorts 
  as 
  are 
  used 
  for 
  the 
  

   final 
  treatment, 
  or 
  by 
  the 
  employment 
  of 
  elongated 
  steam 
  boxes 
  

   through 
  which 
  the 
  cans 
  with 
  the 
  vent 
  open 
  were 
  slowly 
  conveyed. 
  The 
  

   principle 
  involved 
  in 
  these 
  cases 
  is 
  the 
  same. 
  With 
  the 
  vent 
  open 
  the 
  

   excess 
  of 
  air, 
  which 
  it 
  is 
  the 
  aim 
  to 
  expel, 
  or 
  exliaust, 
  escapes 
  gradually 
  

   and 
  evenly 
  through 
  this 
  opening, 
  and 
  is 
  thus 
  a 
  distinct 
  advantage 
  over 
  

  

  