﻿300 
  Mr. 
  E. 
  C. 
  Grey. 
  The 
  Enzymes 
  of 
  B. 
  coli 
  communis 
  

  

  is 
  added 
  at 
  the 
  beginning 
  of 
  such 
  a 
  fermentation 
  the 
  rate 
  of 
  production 
  

   of 
  this 
  product 
  should 
  be 
  diminished, 
  and 
  at 
  the 
  end 
  of 
  the 
  experiment 
  we 
  

   expect 
  to 
  find 
  a 
  lessened 
  accumulation 
  of 
  the 
  substance 
  in 
  question. 
  We 
  

   should 
  accordingly 
  anticipate 
  that 
  formic 
  acid 
  added 
  at 
  the 
  beginning 
  of 
  the 
  

   fermentation 
  would 
  lessen 
  the 
  production 
  of 
  formic 
  acid 
  from 
  the 
  glucose. 
  

   Now, 
  as 
  a 
  matter 
  of 
  fact, 
  the 
  analysis 
  of 
  the 
  solution 
  at 
  the. 
  end 
  of 
  all 
  the 
  

   experiments, 
  except 
  No. 
  1, 
  showed 
  that 
  there 
  was 
  no 
  excess 
  of 
  formic 
  acid 
  

   over 
  that 
  added 
  at 
  the 
  beginning 
  ; 
  but, 
  for 
  obvious 
  reasons, 
  we 
  are 
  not 
  in 
  a 
  

   position 
  to 
  say 
  how 
  much 
  of 
  the 
  formic 
  acid 
  which 
  remained 
  at 
  the 
  end 
  of 
  

   the 
  experiment, 
  if 
  any, 
  had 
  been 
  produced 
  from 
  the 
  glucose 
  and 
  how 
  much 
  

   more 
  merely 
  represented 
  unaltered 
  formic 
  acid 
  added. 
  The 
  striking 
  fact, 
  

   however, 
  is 
  the 
  liberation 
  of 
  such 
  an 
  increased 
  amount 
  of 
  carbon 
  dioxide 
  and 
  

   hydrogen 
  from 
  the 
  glucose, 
  for 
  we 
  have 
  hitherto 
  held 
  the 
  view 
  that 
  these 
  

   gaseous 
  products 
  come 
  from 
  pre-existing 
  formic 
  acid. 
  Now, 
  in 
  these 
  experi- 
  

   ments, 
  in 
  which 
  glucose 
  was 
  fermented 
  in 
  the 
  presence 
  of 
  calcium 
  formate, 
  

   not 
  only 
  the 
  equivalent 
  of 
  all 
  the 
  formic 
  acid 
  which 
  normally 
  is 
  formed 
  by 
  

   the 
  decomposition 
  of 
  the 
  glucose 
  appears 
  as 
  carbon 
  dioxide 
  and 
  hydrogen, 
  but 
  

   the 
  total 
  yield 
  of 
  these 
  gaseous 
  products 
  is 
  greatly 
  enhanced, 
  reaching, 
  as 
  will 
  

   be 
  seen 
  in 
  the 
  figure 
  in 
  the 
  case 
  of 
  Experiment 
  2, 
  to 
  nearly 
  50 
  per 
  cent, 
  of 
  

   the 
  glucose, 
  a 
  value 
  more 
  than 
  double 
  that 
  obtained 
  in 
  the 
  case 
  of 
  the 
  

   fermentation 
  of 
  glucose 
  in 
  the 
  absence 
  of 
  added 
  formate. 
  

  

  How 
  then 
  are 
  we 
  to 
  explain 
  the 
  fact 
  that 
  formic 
  acid 
  which 
  itself 
  is 
  

   decomposed 
  by 
  B. 
  coli 
  into 
  carbon 
  dioxide 
  and 
  hydrogen, 
  increases 
  the 
  

   production 
  of 
  these 
  same 
  gases 
  from 
  glucose 
  when 
  the 
  glucose 
  and 
  formic 
  

   acid 
  are 
  fermented 
  together. 
  

  

  An 
  attempt 
  will 
  be 
  made 
  to 
  answer 
  this 
  question 
  in 
  Part 
  V 
  of 
  this 
  series. 
  

   It 
  seerna 
  to 
  the 
  writer 
  that 
  the 
  answering 
  of 
  the 
  question 
  will 
  necessitate 
  the 
  

   giving 
  up 
  of 
  the 
  prevalent 
  idea 
  as 
  to 
  the 
  manner 
  in 
  which 
  glucose 
  undergoes 
  

   decomposition 
  in 
  fermentation, 
  and 
  that 
  it 
  will 
  be 
  best 
  to 
  reserve 
  the 
  

   discussion 
  until 
  certain 
  other 
  facts 
  are 
  pointed 
  out. 
  

  

  It 
  is 
  possible 
  to 
  see 
  several 
  important 
  relationships 
  from 
  fig. 
  1, 
  but 
  it 
  will 
  

   considerably 
  simplify 
  the 
  consideration 
  of 
  such 
  relationships 
  if 
  all 
  the 
  curves 
  

   can 
  be 
  considered 
  apart 
  from 
  the 
  influence 
  of 
  the 
  lactic 
  acid 
  ; 
  for 
  since 
  the 
  

   course 
  of 
  the 
  lactic 
  acid 
  production 
  runs 
  independently 
  of 
  that 
  of 
  the 
  other 
  

   products 
  we 
  shall 
  be 
  justified 
  in 
  setting 
  aside 
  that 
  portion 
  of 
  the 
  sugar 
  

   which 
  has 
  been 
  converted 
  into 
  lactic 
  acid, 
  and 
  calculating 
  the 
  remaining 
  

   products 
  as 
  percentages 
  upon 
  the 
  remaining 
  portion 
  of 
  the 
  glucose. 
  This 
  

   calculation 
  has 
  been 
  made 
  and 
  the 
  results 
  are 
  tabulated 
  in 
  Table 
  IV. 
  These 
  

   results 
  are 
  further 
  plotted 
  in 
  the 
  form 
  of 
  curve 
  in 
  fig. 
  2 
  in 
  a 
  manner 
  similar 
  

   to 
  that 
  adopted 
  in 
  the 
  construction 
  of 
  fig. 
  1. 
  

  

  