﻿1874,] 
  

  

  President's 
  Address. 
  

  

  69 
  

  

  had 
  a 
  faintly 
  acid 
  reaction 
  — 
  but 
  that 
  when 
  this 
  was 
  neutralized 
  by 
  car- 
  

   bonate 
  of 
  lime, 
  the 
  solutions 
  then 
  behaved 
  like 
  milk. 
  

  

  Prof. 
  Pasteur 
  also 
  examined 
  the 
  gun-cotton 
  through 
  which 
  the 
  air 
  has 
  

   been 
  passed 
  ; 
  and 
  he 
  found, 
  among 
  other 
  things, 
  certain 
  cells 
  to 
  which 
  he 
  

   attributed 
  the 
  power 
  of 
  causing 
  the 
  growth 
  of 
  organisms 
  in 
  solutions. 
  By 
  

   sowing 
  some 
  of 
  these 
  cells 
  in 
  solutions 
  which 
  previously 
  had 
  remained 
  clear, 
  

   and 
  finding 
  that 
  such 
  solutions 
  speedily 
  became 
  turbid 
  from 
  the 
  growth 
  of 
  

   living 
  organisms, 
  it 
  was 
  proved 
  that 
  the 
  air 
  which 
  had 
  passed 
  through 
  

   the 
  gun-cotton 
  had 
  lost 
  its 
  property 
  of 
  causing 
  the 
  development 
  of 
  life 
  in 
  

   solutions 
  because 
  the 
  germs 
  which 
  the 
  air 
  contained 
  had 
  been 
  stopped 
  by 
  

   the 
  gun-cotton. 
  

  

  The 
  result 
  of 
  the 
  second 
  part 
  of 
  the 
  research 
  may 
  be 
  thus 
  summed 
  up 
  : 
  — 
  

  

  1. 
  No 
  organisms 
  are 
  developed 
  in 
  solutions 
  if 
  care 
  be 
  taken 
  to 
  prevent 
  

   the 
  possibility 
  of 
  the 
  presence 
  of 
  germs. 
  

  

  2. 
  This 
  negative 
  result 
  does 
  not 
  depend 
  upon 
  the 
  exclusion 
  of 
  oxygen. 
  

  

  3. 
  The 
  matter 
  separated 
  from 
  ordinary 
  air 
  is 
  competent 
  to 
  develop 
  

   organisms 
  in 
  solutions 
  which 
  previously 
  had 
  remained 
  unchanged. 
  

  

  Not 
  less 
  important 
  were 
  the 
  results 
  of 
  Pasteur's 
  experiments 
  respecting 
  

   tbe 
  chemical 
  functions 
  of 
  the 
  ferment. 
  

  

  It 
  had 
  been 
  held 
  that 
  the 
  entire 
  ferment 
  was 
  in 
  a 
  state 
  of 
  putrefactive 
  

   decomposition, 
  and 
  induced 
  a 
  similar 
  decomposition 
  in 
  the 
  sugar 
  with 
  

   which 
  it 
  was 
  in 
  contact. 
  

  

  In 
  corroboration 
  of 
  this 
  view, 
  it 
  was 
  stated 
  that 
  ammonia 
  (a 
  product 
  of 
  

   the 
  decomposition 
  of 
  albuminous 
  substances 
  such 
  as 
  those 
  present 
  in 
  the 
  

   ferment) 
  is 
  always 
  found 
  in 
  liquids 
  which 
  are 
  undergoing 
  fermentation. 
  

  

  Pasteur 
  proved 
  that 
  the 
  ammonia 
  in 
  fermenting 
  liquids 
  diminishes 
  in 
  

   quantity 
  in 
  proportion 
  as 
  the 
  process 
  advances, 
  and 
  that 
  the 
  yeast-cells 
  

   increase 
  and 
  grow 
  while 
  forming 
  complex 
  albuminous 
  substances 
  at 
  the 
  

   expense 
  of 
  the 
  ammonia 
  and 
  other 
  aliments 
  which 
  are 
  supplied 
  to 
  it. 
  He 
  

   found 
  that, 
  in 
  addition 
  to 
  ammonia 
  and 
  sugar, 
  the 
  cells 
  require 
  mineral 
  

   substances, 
  such 
  as 
  phosphates 
  and 
  other 
  constituents, 
  such 
  as 
  are 
  present 
  

   in 
  the 
  organism 
  of 
  every 
  healthy 
  and 
  growing 
  yeast- 
  cell. 
  

  

  In 
  short, 
  he 
  proved 
  that 
  those 
  conditions 
  which 
  are 
  most 
  favourable 
  to 
  

   the 
  healthy 
  growth 
  and 
  development 
  of 
  the 
  yeast-cells 
  are 
  most 
  conducive 
  

   to 
  the 
  progress 
  of 
  fermentation, 
  and 
  that 
  fermentation 
  is 
  impeded 
  or 
  

   arrested 
  by 
  those 
  influences 
  which 
  check 
  the 
  growth 
  or 
  destroy 
  the 
  vitality 
  

   of 
  the 
  cell. 
  

  

  The 
  above 
  results 
  are 
  but 
  samples 
  of 
  the 
  fruits 
  of 
  Pasteur's 
  long 
  series 
  

   of 
  researches 
  in 
  this 
  subject. 
  Many 
  and 
  many 
  an 
  able 
  investigator 
  had 
  

   worked 
  in 
  the 
  same 
  field 
  ; 
  and 
  such 
  were 
  the 
  difficulties 
  they 
  encountered, 
  

   that 
  Dumas 
  himself 
  recommended 
  Pasteur 
  not 
  to 
  waste 
  his 
  time 
  in 
  working 
  

   at 
  so 
  hopeless 
  a 
  subject. 
  

  

  To 
  the 
  biologist, 
  two 
  of 
  Pasteur's 
  researches 
  are 
  of 
  very 
  great 
  interest 
  

   and 
  importance. 
  He 
  has 
  shown 
  that 
  Fungi 
  find 
  all 
  the 
  materials 
  needed 
  

   for 
  their 
  nutrition 
  and 
  growth 
  in 
  water 
  containing 
  an 
  ammonia 
  salt 
  and 
  

  

  