﻿206 
  

  

  Prof. 
  B. 
  Moore 
  and 
  Mr. 
  T. 
  A. 
  Webster. 
  

  

  these 
  may 
  be 
  omitted. 
  The 
  growth 
  in 
  the 
  open 
  flask 
  remained 
  green 
  and 
  

   healthy 
  to 
  the 
  end. 
  No 
  fresh 
  growth 
  started 
  in 
  the 
  stoppered 
  one, 
  and 
  at 
  

   the 
  end 
  it 
  had 
  only 
  a 
  very 
  few 
  brown 
  flocculi 
  from 
  the 
  initial 
  effort, 
  ere 
  its 
  

   small 
  store 
  of 
  dissolved 
  carbon 
  dioxide 
  and 
  nitrogen 
  became 
  exhausted. 
  

   The 
  contrast 
  at 
  the 
  end 
  between 
  the 
  two 
  flasks 
  was 
  most 
  marked. 
  

  

  Frequent 
  examination 
  with 
  the 
  microscope, 
  through 
  the 
  wall 
  of 
  the 
  flask, 
  

   of 
  the 
  growing 
  clumps 
  of 
  green 
  organisms, 
  showed 
  the 
  presence 
  of 
  only 
  two 
  

   types 
  of 
  round-celled 
  unicellular 
  algfe. 
  One 
  of 
  these 
  was 
  smaller 
  than 
  the 
  

   other 
  and 
  of 
  a 
  brighter 
  green, 
  and 
  was 
  identified 
  as 
  Chlorella 
  ; 
  the 
  other 
  was 
  

   of 
  about 
  twice 
  the 
  diameter, 
  not 
  so 
  regularly 
  spherical, 
  and 
  of 
  a 
  brownish- 
  

   green 
  colour. 
  There 
  were 
  no 
  Diatoms 
  or 
  other 
  motile 
  green 
  organisms. 
  No 
  

   mycelium 
  or 
  other 
  evidence 
  of 
  fungi 
  were 
  seen, 
  and 
  the 
  absence 
  of 
  any 
  

   turbidity 
  at 
  the 
  end 
  showed 
  there 
  was 
  no 
  appreciable 
  development 
  of 
  

   bacteria. 
  Drops 
  examined 
  at 
  the 
  end 
  showed 
  no 
  bacterial 
  growths. 
  

  

  Blank 
  experiments 
  on 
  the 
  water 
  used 
  showed 
  that 
  it 
  contained 
  about 
  

   1 
  mgrm. 
  per 
  litre 
  of 
  amino-nitrogen, 
  and 
  about 
  0*3 
  mgrm. 
  per 
  litre 
  of 
  

   nitrogen 
  as 
  nitrite 
  and 
  nitrate. 
  In 
  addition 
  to 
  this 
  control, 
  there 
  is 
  the 
  

   control 
  of 
  the 
  stoppered 
  flask 
  contents. 
  

  

  The 
  contents 
  of 
  the 
  two 
  flasks 
  were 
  analysed 
  on 
  August 
  5. 
  The 
  water 
  in 
  

   each, 
  slightly 
  acidified 
  with 
  sulphuric 
  acid 
  to 
  prevent 
  any 
  loss 
  of 
  amino- 
  

   nitrogen, 
  was 
  evaporated 
  down 
  almost 
  to 
  dryness 
  ; 
  then 
  in 
  each 
  case 
  the 
  

   growth 
  was 
  added 
  ; 
  destruction 
  with 
  sulphuric 
  acid 
  followed, 
  and 
  the 
  

   nitrogen 
  determination 
  was 
  made 
  by 
  the 
  ordinary 
  Kjeldahl's 
  process. 
  

  

  The 
  results 
  were 
  that 
  the 
  open 
  flask 
  contained 
  5 
  - 
  00 
  mgrm. 
  of 
  nitrogen, 
  

   while 
  the 
  stoppered 
  flask 
  contained 
  only 
  1*95 
  mgrm. 
  A 
  third 
  flask 
  of 
  

   transparent 
  silica, 
  containing 
  the 
  same 
  water, 
  which 
  had 
  been 
  exposed 
  

   during 
  the 
  entire 
  period 
  of 
  the 
  experiment 
  to 
  such 
  bright 
  and 
  direct 
  

   sunlight 
  as 
  was 
  available, 
  developed 
  no 
  growth 
  whatever 
  ; 
  probably 
  because 
  

   the 
  cells 
  were 
  destroyed 
  by 
  the 
  intenser 
  light 
  and 
  shorter 
  wave-lengths. 
  

   The 
  water 
  in 
  this 
  flask 
  was 
  examined 
  similarly 
  to 
  the 
  two 
  above, 
  and 
  

   yielded 
  T80 
  mgrm. 
  per 
  litre. 
  There 
  is 
  thus 
  a 
  distinct 
  and 
  quite 
  unmistakable 
  

   gain 
  of 
  3"05 
  mgrm., 
  which 
  has 
  no 
  other 
  conceivable 
  source 
  than 
  the 
  atmo- 
  

   sphere. 
  It 
  may 
  be 
  pointed 
  out 
  that 
  this 
  weight 
  of 
  nitrogen 
  roughly 
  

   corresponds 
  to 
  about 
  100 
  mgrm. 
  of 
  dried 
  algas, 
  or 
  to 
  500 
  mgrm., 
  or 
  about 
  

   half 
  a 
  gramme, 
  of 
  moist-plant. 
  It 
  is 
  an 
  increase 
  in 
  nitrogen, 
  lying 
  many 
  

   times 
  outside 
  the 
  limits 
  of 
  error 
  of 
  the 
  analytical 
  methods 
  employed. 
  

  

  Experiment 
  2. 
  — 
  Commenced 
  May 
  31, 
  1918 
  ; 
  terminated 
  September 
  9, 
  

   1918. 
  This 
  experiment 
  was 
  carried 
  out 
  in 
  a 
  series 
  of 
  twelve 
  screw-stoppered 
  

   fruit 
  preserving 
  jars, 
  called 
  "Kilners," 
  each 
  of 
  about 
  850 
  c.c. 
  capacity. 
  

   These 
  jars 
  are 
  of 
  pale-green 
  bottle-glass, 
  and 
  possess 
  a 
  flat 
  flange 
  at 
  top, 
  

  

  