﻿Organisms 
  and 
  Nucleic 
  Acid 
  Derivatives 
  on 
  Plant 
  Growth. 
  87 
  

  

  neutralising 
  with 
  hydrochloric 
  acid, 
  were 
  concentrated 
  in 
  vacuo 
  and 
  divided 
  

   into 
  two 
  equal 
  portions, 
  to 
  one 
  of 
  which 
  a 
  few 
  drops 
  of 
  chloroform 
  were 
  

   added, 
  in 
  order 
  to 
  prevent 
  bacterial 
  growth. 
  This 
  liquid 
  was 
  preserved 
  in 
  a 
  

   bottle 
  and 
  known 
  as 
  " 
  crude 
  nucleic 
  acid 
  derivatives 
  from 
  raw 
  peat." 
  To 
  the 
  

   other 
  half 
  a 
  little 
  sodium 
  acetate 
  was 
  added, 
  and 
  sufficient 
  hydrochloric 
  acid 
  

   to 
  render 
  the 
  liquid 
  acid 
  to 
  .litmus, 
  and 
  then 
  about 
  twice 
  its 
  volume 
  of 
  

   absolute 
  alcohol 
  to 
  completely 
  precipitate 
  the 
  dinucleotide. 
  After 
  24 
  hours 
  

   the 
  liquid 
  was 
  decanted 
  off 
  through 
  a 
  filter, 
  the 
  precipitate 
  washed 
  with 
  a 
  

   little 
  absolute 
  alcohol, 
  allowed 
  to 
  settle, 
  and 
  the 
  liquid 
  again 
  decanted. 
  This 
  

   was 
  repeated 
  until 
  the 
  alcohol 
  was 
  no 
  longer 
  coloured. 
  The 
  precipitate 
  was 
  

   then 
  dried 
  in 
  vacuo 
  and 
  dissolved 
  up 
  in 
  a 
  very 
  slight 
  excess 
  of 
  sodium 
  

   carbonate 
  solution, 
  the 
  excess 
  being 
  finally 
  carefully 
  neutralised 
  with 
  dilute 
  

   hydrochloric 
  acid. 
  When 
  made 
  up 
  to 
  a 
  known 
  volume 
  a 
  few 
  drops 
  of 
  chloro- 
  

   form 
  were 
  added, 
  and 
  the 
  liquid, 
  bottled 
  for 
  use, 
  was 
  known 
  as 
  " 
  adenine- 
  

   uracil 
  dinucleotide 
  from 
  raw 
  peat." 
  

  

  An 
  experiment 
  was 
  then 
  made 
  in 
  June, 
  1917, 
  to 
  test 
  the 
  effect 
  on 
  the 
  

   growth 
  of 
  Zemna 
  minor 
  of 
  each 
  of 
  these 
  fractions 
  from 
  raw 
  peat, 
  in 
  

   comparison 
  with 
  that 
  of 
  Azotobacter 
  ckroococcum 
  and 
  of 
  bacterised 
  peat. 
  A 
  set 
  

   of 
  thirty 
  dishes 
  was 
  arranged 
  in 
  six 
  series 
  of 
  five 
  dishes 
  each, 
  and 
  all 
  

   contained 
  150 
  c.c. 
  of 
  Detmer's 
  solution 
  with 
  the 
  following 
  additions 
  : 
  — 
  

   Series 
  I, 
  numbered 
  from 
  1 
  to 
  5, 
  no 
  addition 
  ; 
  Series 
  II, 
  numbered 
  from 
  6 
  to 
  

   10, 
  the 
  crude 
  nucleic 
  acid 
  derivatives 
  from 
  1 
  grin, 
  of 
  raw 
  peat 
  in 
  every 
  

   500 
  c.c. 
  ; 
  Series 
  III, 
  numbered 
  from 
  11 
  to 
  15, 
  the 
  adenine-uracil 
  dinucleotide 
  

   from 
  1 
  grm. 
  of 
  raw 
  peat 
  per 
  500 
  c.c. 
  ; 
  Series 
  IV, 
  numbered 
  from 
  16 
  to 
  20, 
  

   - 
  5 
  grm. 
  of 
  the 
  autoclaved 
  growth 
  of 
  Azotobacter 
  chroococcum 
  per 
  500 
  c.c. 
  ; 
  

   Series 
  V, 
  numbered 
  from 
  21 
  to 
  25, 
  the 
  crude 
  nucleic 
  acid 
  derivatives 
  from 
  

   1 
  grm. 
  of 
  raw 
  peat 
  plus 
  - 
  5 
  gram 
  of 
  the 
  growth 
  of 
  Azotobacter 
  chroococcum 
  

   per 
  500 
  c.c, 
  i.e., 
  the 
  addition 
  made 
  in 
  Series 
  II 
  plus 
  that 
  made 
  in 
  Series 
  IV 
  • 
  

   and 
  Series 
  VI, 
  numbered 
  from 
  25 
  to 
  30, 
  the 
  water 
  extract 
  of 
  1 
  grm. 
  of 
  

   bacterised 
  peat 
  per 
  500 
  c.c. 
  

  

  When 
  the 
  various 
  extracts 
  were 
  required 
  for 
  use, 
  the 
  requisite 
  quantities 
  of 
  

   the 
  respective 
  liquids 
  were 
  measured 
  out 
  from 
  the 
  stock 
  bottles, 
  transferred 
  

   to 
  evaporating 
  basins, 
  and 
  warmed 
  on 
  the 
  water-bath 
  to 
  a 
  temperature 
  of 
  

   80° 
  C. 
  to 
  expel 
  the 
  chloroform. 
  When 
  cold 
  they 
  were 
  added 
  to 
  the 
  concen- 
  

   trated 
  Detmer's 
  solution 
  and 
  made 
  up 
  to 
  the 
  required 
  volume 
  with 
  con- 
  

   ductivity 
  water. 
  

  

  Ten 
  plants 
  of 
  Lemna 
  minor 
  were 
  counted 
  out 
  into 
  each 
  dish, 
  300 
  similar 
  

   plants 
  being 
  counted 
  out 
  at 
  the 
  same 
  time 
  for 
  an 
  estimation 
  of 
  their 
  dry 
  

   weight. 
  The 
  dishes 
  were 
  covered 
  with 
  paper 
  to 
  the 
  level 
  of 
  the 
  liquid, 
  as 
  

   described 
  above, 
  to 
  cut 
  out 
  the 
  light 
  from 
  the 
  bottom 
  and 
  sides, 
  and 
  placed 
  in 
  

  

  