﻿Studies 
  of 
  Photo-synthesis 
  in 
  Fresh-water 
  AlgcB. 
  203 
  

  

  nitrogen, 
  have 
  convinced 
  us 
  that 
  the 
  experimental 
  results 
  of 
  these 
  observers 
  

   were 
  correct, 
  but 
  their 
  deductions 
  profoundly 
  erroneous. 
  The 
  seedlings 
  we 
  

   obtained 
  were 
  dwarfs, 
  although 
  they 
  flowered 
  and 
  seeded, 
  and 
  they 
  assimi- 
  

   lated 
  scarcely 
  any 
  nitrogen. 
  This 
  does 
  not 
  by 
  any 
  means 
  settle 
  the 
  problem 
  ; 
  

   it 
  only 
  proves 
  that, 
  so 
  far 
  as 
  the 
  higher 
  plants 
  are 
  concerned, 
  this 
  is 
  an 
  

   abortive 
  method 
  of 
  experimentation. 
  If 
  the 
  conditions 
  of 
  enviroment 
  are 
  

   such 
  as 
  to 
  make 
  any 
  feeble 
  growth 
  pathological, 
  and 
  if 
  the 
  dry 
  weight 
  of 
  the 
  

   plant 
  scarcely 
  exceeds 
  that 
  of 
  the 
  seed 
  from 
  which 
  it 
  grew, 
  it 
  is 
  scarcely 
  to 
  

   be 
  expected 
  that 
  there 
  should 
  be 
  an 
  increase 
  in 
  nitrogen. 
  On 
  the 
  other 
  

   hand, 
  had 
  the 
  seeds 
  grown 
  into 
  anything 
  like 
  normal 
  plants, 
  it 
  would 
  have 
  

   been 
  an 
  unthinkable 
  monstrosity 
  in 
  nature 
  that 
  carbon, 
  hydrogen, 
  and 
  oxygen 
  

   should 
  go 
  up 
  without 
  any 
  accompanying 
  increase 
  in 
  the 
  nitrogen. 
  

  

  It 
  has 
  been 
  shown 
  by 
  Jamieson 
  (1), 
  in 
  several 
  species 
  of 
  higher 
  plants, 
  that 
  

   when 
  a 
  minimal 
  amount 
  of 
  nitrogen 
  is 
  supplied, 
  these 
  grow, 
  increase 
  in 
  

   weight, 
  and 
  form 
  far 
  more 
  combined 
  nitrogen 
  both 
  in 
  soil 
  and 
  plant 
  than 
  has 
  

   been 
  supplied 
  in 
  original 
  soil 
  and 
  added 
  media. 
  These 
  experiments 
  of 
  

   Jamieson's 
  were 
  carried 
  out 
  with 
  the 
  utmost 
  care, 
  attention 
  being 
  paid 
  to 
  

   every 
  possible 
  source 
  of 
  gain 
  or 
  loss 
  of 
  nitrogen. 
  Moreover, 
  they 
  are 
  

   supported 
  by 
  several 
  other 
  series 
  of 
  observations, 
  such 
  as 
  gain 
  of 
  nitrogen 
  in 
  

   aquatic 
  plants 
  with 
  no 
  soil 
  roots, 
  growth 
  of 
  large 
  trees 
  rooted 
  in 
  clefts 
  in 
  

   basaltic 
  and 
  granitic 
  rocks, 
  where 
  the 
  total 
  nitrogen 
  in 
  the 
  soil 
  could 
  not 
  

   afford 
  sufficient 
  for 
  one 
  annual 
  crop 
  of 
  leaves, 
  analysis 
  for 
  nitrogen 
  of 
  plants 
  

   found 
  growing 
  in 
  hard 
  mortar 
  in 
  walls 
  where 
  the 
  amount 
  of 
  nitrogen 
  avail- 
  

   able, 
  except 
  from 
  the 
  atmosphere, 
  was 
  practically 
  negligible. 
  

  

  A 
  careful 
  perusal 
  of 
  the 
  wealth 
  of 
  facts 
  published 
  by 
  Jamieson 
  in 
  the 
  

   ' 
  Annual 
  Eeports 
  of 
  the 
  Aberdeen 
  Agricultural 
  Eesearch 
  Association,' 
  against 
  

   which 
  there 
  are 
  only 
  to 
  be 
  set 
  these 
  negative 
  results 
  of 
  Boussingault 
  and 
  

   Lawes, 
  is 
  convincing 
  to 
  us 
  as 
  to 
  the 
  positive 
  solution 
  of 
  the 
  problem 
  in 
  favour 
  

   of 
  the 
  assimilation 
  of 
  nitrogen 
  from 
  the 
  air 
  by 
  the 
  green 
  cell. 
  These 
  results 
  

   have 
  been 
  confirmed 
  by 
  Mameli 
  and 
  Pollacci(2) 
  at 
  Pavia; 
  they 
  are 
  rein- 
  

   forced 
  by 
  the 
  experiments 
  in 
  this 
  paper 
  upon 
  Fresh-water 
  Algas, 
  and 
  also 
  by 
  

   others 
  shortly 
  to 
  appear 
  made 
  upon 
  Marine 
  Algae. 
  

  

  Our 
  own 
  approach 
  to 
  this 
  problem 
  has 
  been 
  from 
  a 
  different 
  point 
  of 
  view 
  

   from 
  those 
  who 
  have 
  preceded 
  us 
  ; 
  they 
  have 
  been 
  engaged 
  in 
  its 
  considera- 
  

   tion 
  in 
  relation 
  to 
  the 
  bio-chemistry 
  of 
  the 
  plant, 
  or 
  its 
  importance 
  in 
  

   nutrition 
  in 
  agricultural 
  chemistry 
  ; 
  we 
  have 
  been 
  investigating 
  the 
  matter 
  

   from 
  the 
  point 
  of 
  view 
  of 
  the 
  primaeval 
  origin 
  of 
  living 
  organisms, 
  before 
  

   there 
  was 
  yet 
  anything 
  so 
  complicated 
  as 
  a 
  green 
  cell 
  upon 
  the 
  earth, 
  and 
  

   when 
  organic 
  compounds 
  were 
  first 
  being 
  synthesjsed 
  from 
  inorganic 
  sources. 
  

  

  The 
  minutest 
  micrococcus 
  visible 
  under 
  the 
  microscope 
  contains 
  organic 
  

  

  K 
  2 
  

  

  