﻿208 
  INTRODUCTION 
  TO 
  BOTANY 
  

  

  In 
  the 
  preservation 
  of 
  fruits 
  much 
  progress 
  has 
  been 
  made 
  

   by 
  improvements 
  in 
  methods 
  of 
  gathering 
  them. 
  Most 
  fruits 
  

   have 
  a 
  natural 
  covering, 
  which, 
  if 
  unbroken 
  or 
  unbruised 
  and 
  

   kept 
  clean, 
  will 
  for 
  a 
  long 
  time 
  prevent 
  the 
  entrance 
  of 
  organ- 
  

   isms 
  of 
  decay. 
  If 
  two 
  sets 
  of 
  ripe 
  apples 
  are 
  gathered 
  --one 
  

   carelessly, 
  so 
  that 
  bruising 
  and 
  scratching 
  of 
  the 
  surface 
  occurs, 
  

   the 
  other 
  with 
  sufficient 
  care 
  to 
  avoid 
  these 
  injuries 
  --and 
  both 
  

   are 
  kept 
  under 
  .similar 
  conditions, 
  an 
  interesting 
  demonstration 
  

   will 
  be 
  made 
  of 
  the 
  desirability 
  of 
  proper 
  care 
  in 
  handling 
  fruit. 
  

  

  193. 
  Refrigeration 
  and 
  drying. 
  Long 
  before 
  it 
  was 
  known 
  

   how 
  decay 
  is 
  produced, 
  it 
  was 
  known 
  that 
  low 
  temperature 
  

   and 
  drying 
  would 
  prevent 
  decay. 
  Refrigeration 
  has 
  now 
  be- 
  

   come 
  the 
  chief 
  method 
  of 
  preventing 
  decay, 
  since 
  bacteria 
  do 
  

   not 
  thrive 
  at 
  or 
  below 
  the 
  free/, 
  ing 
  point. 
  There 
  is 
  doubt 
  

   whether 
  bacteria 
  grow 
  at 
  all 
  when 
  at 
  freezing 
  temperature, 
  

   but 
  this 
  point 
  is 
  not 
  definitely 
  settled. 
  Foods 
  are 
  kept 
  for 
  

   years 
  by 
  cold 
  or 
  by 
  drying, 
  and 
  are 
  thus 
  shipped 
  all 
  over 
  the 
  

   world. 
  Fruits, 
  meats, 
  and 
  grains, 
  when 
  completely 
  dried 
  (a 
  

   natural 
  process 
  of 
  preservation), 
  may 
  be 
  kept 
  for 
  years, 
  since 
  

   destructive 
  bacteria 
  cannot 
  thrive 
  upon 
  thoroughly 
  dry 
  food. 
  

   Preservation 
  in 
  salt 
  and 
  sugar 
  or 
  their 
  strong 
  solutions 
  serves 
  

   the 
  same 
  purpose 
  as 
  drying, 
  since 
  salt 
  and 
  sugar 
  have 
  such 
  

   avidity 
  for 
  water 
  that 
  destructive 
  organisms 
  have 
  their 
  proto- 
  

   plasmic 
  water 
  extracted 
  and 
  therefore 
  cannot 
  grow. 
  Fish, 
  

   beef, 
  pork, 
  and 
  other 
  meats 
  may 
  be 
  preserved 
  by 
  smoking 
  

   with 
  wood 
  smoke. 
  The 
  creosote 
  that 
  is 
  carried 
  into 
  the 
  meat 
  

   by 
  this 
  process 
  helps 
  to 
  prevent 
  the 
  growth 
  of 
  destructive 
  

   organisms. 
  This 
  method 
  of 
  preservation, 
  though 
  thoroughly 
  

   wholesome, 
  requires 
  long 
  exposure 
  to 
  the 
  smoke. 
  It 
  is 
  not 
  so 
  

   extensively 
  used 
  for 
  beef 
  and 
  pork 
  as 
  formerly, 
  though 
  large 
  

   quantities 
  of 
  fish 
  are 
  still 
  preserved 
  in 
  this 
  manner. 
  

  

  194. 
  Sterilization 
  and 
  canning. 
  High 
  temperature 
  may 
  also 
  

   prevent 
  the 
  growth 
  of 
  bacteria, 
  and 
  by 
  its 
  use 
  sterilization 
  

   and 
  canning 
  have 
  recently 
  offered 
  very 
  great 
  opportunities 
  for 
  

   food 
  preservation 
  and 
  shipment. 
  By 
  means 
  of 
  heat 
  properly 
  

   applied 
  all 
  bacteria 
  and 
  other 
  organisms 
  of 
  decay 
  may 
  be 
  

  

  