﻿518 
  KEPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  The 
  chemical 
  analj'sis 
  of 
  VaUlsnerm 
  .shows 
  that 
  the 
  metaholism 
  of 
  

   plants 
  denied 
  a 
  substratum 
  is 
  ver}' 
  different 
  from 
  that 
  of 
  plants 
  allowed 
  

   to 
  root 
  in 
  the 
  soil. 
  The 
  former 
  show 
  a 
  marked 
  excess 
  of 
  calcium 
  and 
  

   magnesium, 
  while 
  the 
  latter 
  contain 
  a 
  larger 
  proportion 
  of 
  protein, 
  

   potassium, 
  and 
  phosphorus. 
  This 
  change 
  of 
  metabolism 
  manifests 
  

   itself 
  outwardl}^ 
  by 
  a 
  greatl}' 
  retarded 
  growth, 
  and 
  microscopic 
  exam- 
  

   ination 
  reveals 
  that 
  an 
  abnormal 
  amount 
  of 
  starch 
  has 
  accumulated 
  in 
  

   the 
  tissues. 
  This 
  accumulation 
  of 
  starch 
  is 
  so 
  great 
  that 
  the 
  dr}^ 
  weight 
  

   of 
  a 
  given 
  fresh 
  volume 
  is 
  considerably 
  more 
  than 
  is 
  obtained 
  from 
  an 
  

   equal 
  fresh 
  volume 
  of 
  plants 
  grown 
  rooted 
  in 
  the 
  soil. 
  

  

  The 
  last 
  experiment, 
  No. 
  17, 
  with 
  Ranunculus^ 
  shows 
  that 
  light 
  is 
  

   the 
  factor 
  which 
  prevents 
  the 
  formation 
  of 
  lateral 
  roots 
  and 
  which 
  also 
  

   retards 
  the 
  growth 
  of 
  the 
  main 
  root. 
  However, 
  the 
  more 
  elaborate 
  

   root 
  system 
  which 
  develops 
  in 
  the 
  dark 
  does 
  not 
  aid 
  the 
  plant 
  to 
  make 
  

   a 
  proportionately 
  greater 
  growth 
  when 
  the 
  roots 
  are 
  not 
  allowed 
  to 
  

   enter 
  the 
  soil. 
  

  

  From 
  the 
  aquarium 
  experiments 
  it 
  is 
  evident 
  that 
  these 
  attached 
  

   aquatics 
  are 
  dependent 
  upon 
  the 
  soil 
  for 
  optimum 
  grow^th. 
  Not 
  one 
  

   of 
  the 
  species 
  investigated, 
  except 
  possibly 
  Chara,^ 
  can 
  survive 
  the 
  

   growing 
  season 
  unless 
  rooted 
  in 
  the 
  soil, 
  and 
  even 
  Chara 
  does 
  not 
  

   make 
  an 
  optimum 
  growth 
  under 
  any 
  other 
  conditions. 
  

  

  While 
  the 
  aquarium 
  experiments 
  establish 
  the 
  fact 
  as 
  stated, 
  they 
  

   do 
  not 
  furnish 
  adequate 
  explanation 
  of 
  the 
  fact. 
  It 
  may 
  first 
  be 
  asked: 
  

   Does 
  the 
  soil 
  furnish 
  plants 
  rooted 
  in 
  it 
  with 
  substances 
  that 
  are 
  not 
  

   available 
  for 
  plants 
  suspended 
  in 
  the 
  water 
  over 
  it? 
  

  

  Concerning 
  this 
  question 
  w^e 
  may 
  consider, 
  first, 
  that 
  soils 
  have 
  the 
  

   property 
  of 
  withdrawing 
  salts 
  from 
  solution. 
  Way 
  (1850) 
  discovered 
  

   that 
  liquid 
  manure 
  filters 
  through 
  soil 
  to 
  a 
  clear 
  solution 
  containing 
  both 
  

   organic 
  and 
  inorganic 
  matter 
  in 
  diminished 
  quantity. 
  Liebig 
  (1858, 
  

   p. 
  100) 
  and 
  others 
  took 
  up 
  the 
  matter 
  until 
  this 
  absorptive 
  capacity 
  of 
  

   soils 
  is 
  well 
  established. 
  For 
  a 
  time 
  authors 
  were 
  divided 
  as 
  to 
  whether 
  

   this 
  fixation, 
  or 
  rather 
  retention, 
  of 
  salts 
  by 
  the 
  soil 
  is 
  a 
  physical 
  or 
  

   chemical 
  process, 
  but 
  the 
  general 
  agreement 
  now 
  is 
  that 
  both 
  phys- 
  

   ical 
  and 
  chemical 
  processes 
  operate. 
  (Kubel-Tiemann-Gartner, 
  1889.) 
  

   Ff 
  efl'er 
  (1000, 
  p. 
  166), 
  summarizing 
  from 
  the 
  various 
  researches, 
  states 
  

   that 
  most 
  soils 
  absorb 
  the 
  oxides, 
  salts 
  of 
  the 
  alkalies, 
  and 
  alkaline 
  

   earths 
  of 
  potassium, 
  ammonium, 
  magnesium, 
  sodium, 
  and 
  calcium 
  in 
  

   relative 
  quantities 
  in 
  the 
  order 
  mentioned. 
  It 
  must 
  be 
  remembered, 
  

   however, 
  that 
  this 
  retention 
  of 
  dissolved 
  substances 
  by 
  the 
  soil 
  is 
  

   neither 
  absolute 
  nor 
  permanent. 
  

  

  In 
  the 
  case 
  of 
  the 
  lake 
  there 
  are 
  x>robably 
  operating 
  two 
  opposing 
  

  

  « 
  Davis 
  (1901) 
  states 
  that 
  culture 
  experiments 
  made 
  by 
  him 
  demonstrated 
  the 
  fact 
  

   that 
  Chnra 
  takes 
  its 
  lime 
  from 
  the 
  water 
  and 
  not 
  from 
  the 
  soil. 
  However 
  this 
  may- 
  

   be, 
  it 
  is 
  certainly 
  true 
  that 
  Chara 
  makes 
  its 
  best 
  and 
  most 
  vigorous 
  gro\\th 
  when 
  

   rooted 
  in 
  a 
  good 
  soil. 
  

  

  