﻿The 
  Enzymes 
  o/B. 
  coli 
  communis. 
  295 
  

  

  The 
  present 
  experiments 
  were 
  undertaken 
  rather 
  with 
  the 
  object 
  of 
  seeing 
  

   whether 
  the 
  hydrogen 
  nascent 
  during 
  the 
  decomposition 
  of 
  formates 
  could 
  

   give 
  rise 
  to 
  an 
  increased 
  yield 
  of 
  alcohol 
  from 
  the 
  glucose. 
  In 
  one 
  case 
  such 
  

   an 
  increase 
  actually 
  occurred, 
  but 
  in 
  most 
  cases 
  the 
  reverse 
  was 
  the 
  case. 
  

   On 
  the 
  other 
  hand, 
  the 
  results 
  have 
  been 
  valuable 
  in 
  themselves 
  for 
  the 
  

   reason 
  stated 
  above. 
  

  

  must 
  be 
  confessed 
  that 
  the 
  concentrations 
  of 
  calcium 
  formate 
  employed 
  

   i. 
  hese 
  experiments 
  appear 
  to 
  have 
  been 
  chosen 
  somewhat 
  at 
  random. 
  

   One 
  of 
  the 
  reasons 
  for 
  this 
  is 
  the 
  difficulty 
  of 
  deciding 
  upon 
  the 
  use 
  of 
  

   varying 
  concentrations 
  of 
  calcium 
  formate, 
  and 
  at 
  the 
  same 
  time 
  keeping 
  the 
  

   concentration 
  of 
  salts 
  within 
  proper 
  bounds. 
  The 
  criticism 
  which 
  may 
  be 
  

   raised 
  on 
  these 
  grounds 
  in 
  regard 
  to 
  the 
  order 
  in 
  which 
  these 
  experiments 
  

   were 
  carried 
  out 
  does 
  not, 
  however, 
  in 
  any 
  way 
  concern 
  the 
  conclusions 
  

   which 
  are 
  drawn 
  in 
  the 
  present 
  communication. 
  The 
  results 
  are 
  considered 
  

   alone 
  in 
  their 
  relation 
  to 
  one 
  another 
  and 
  not 
  in 
  regard 
  to 
  the 
  cause, 
  what- 
  

   ever 
  it 
  may 
  be, 
  which 
  is 
  responsible 
  for 
  them. 
  

  

  Outline 
  of 
  the 
  Method 
  Employed. 
  

  

  An 
  emulsion 
  of 
  B. 
  coli 
  communis 
  was 
  prepared 
  by 
  the 
  method 
  described 
  in 
  

   Part 
  II, 
  and 
  a 
  quantity 
  representing 
  about 
  0'5 
  grm. 
  of 
  dried 
  bacteria 
  was 
  

   added 
  to 
  a 
  solution 
  previously 
  sterilised 
  by 
  heat, 
  containing 
  either 
  glucose, 
  

   or 
  glucose 
  together 
  with 
  calcium 
  formate. 
  The 
  solution 
  also 
  contained 
  

   potassium 
  sulphate 
  - 
  6 
  per 
  cent., 
  and 
  magnesium 
  sulphate 
  01 
  per 
  cent, 
  as 
  in 
  

   Part 
  III. 
  Chalk 
  was 
  added 
  to 
  neutralise 
  the 
  acid 
  which 
  might 
  arise 
  during 
  

   the 
  fermentation. 
  

  

  In 
  order 
  to 
  know 
  the 
  proportion 
  of 
  the 
  products 
  which 
  arise 
  trom 
  the 
  

   glucose, 
  it 
  is 
  necessary 
  to 
  subtract 
  from 
  the 
  total 
  products 
  those 
  which 
  arise 
  

   from 
  the 
  decomposition 
  of 
  the 
  added 
  formate. 
  Accordingly 
  it 
  is 
  necessary 
  

   to 
  determine 
  at 
  the 
  end 
  of 
  each 
  experiment 
  how 
  much 
  formic 
  acid 
  remains, 
  

   and 
  to 
  deduct 
  from 
  the 
  gaseous 
  products 
  an 
  amount 
  of 
  hydrogen 
  and 
  carbon 
  

   dioxide 
  equivalent 
  to 
  the 
  formic 
  acid 
  which 
  has 
  been 
  fermented. 
  

  

  In 
  most 
  cases 
  the 
  amount 
  of 
  formic 
  acid 
  present 
  at 
  the 
  end 
  of 
  the 
  experi- 
  

   ment 
  was 
  less 
  than 
  at 
  the 
  start 
  although, 
  considering 
  the 
  large 
  amount 
  of 
  gases 
  

   evolved, 
  it 
  was 
  surprising 
  to 
  find 
  that 
  the 
  actual 
  diminution 
  in 
  formic 
  acid 
  

   was 
  not 
  great. 
  The 
  formic 
  acid 
  was 
  never 
  exhausted, 
  and 
  in 
  one 
  case 
  there 
  

   was 
  an 
  actual 
  increase 
  in 
  the 
  formic 
  acid 
  over 
  that 
  present 
  at 
  the 
  start. 
  

  

  The 
  data 
  for 
  a 
  series 
  of 
  experiments 
  are 
  given 
  in 
  Tables 
  I 
  and 
  II. 
  

  

  2 
  A 
  2 
  

  

  