﻿512 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  The 
  bottle 
  having 
  been 
  immersed 
  in 
  the 
  aquarium, 
  the 
  root 
  is 
  inclosed 
  by 
  the 
  

   two 
  halves 
  of 
  the 
  stopper 
  and 
  the 
  preparation 
  set 
  up 
  as 
  figured. 
  Air 
  must 
  be 
  

   excluded 
  from 
  the 
  bottle 
  and 
  indicating 
  tube. 
  The 
  water 
  level 
  in 
  the 
  tube 
  and 
  that 
  

   in 
  the 
  aquarium 
  must 
  coincide 
  when 
  the 
  experiment 
  begins. 
  If 
  the 
  preparation 
  is 
  

   successful 
  a 
  change 
  of 
  temperature 
  in 
  the 
  aquarium 
  water 
  will 
  cause 
  a 
  correspond- 
  

   ing 
  change 
  in 
  the 
  level 
  of 
  water 
  in 
  the 
  tube. 
  After 
  this 
  test 
  is 
  made 
  and 
  a 
  uniform 
  

   temperature 
  established, 
  the 
  experiment 
  maj' 
  begin. 
  When 
  the 
  experiment 
  is 
  con- 
  

   cluded 
  the 
  water 
  level 
  in 
  the 
  aquarium 
  must 
  be 
  the 
  original 
  level 
  and 
  the 
  origi- 
  

   nal 
  temperature 
  must 
  be 
  secured. 
  If 
  under 
  these 
  conditions 
  the 
  level 
  of 
  the 
  water 
  

   in 
  the 
  tube 
  is 
  below 
  the 
  level 
  of 
  the 
  water 
  in 
  the 
  aquarium, 
  the 
  root 
  must 
  have 
  

   absorbed 
  a 
  volume 
  of 
  water 
  equal 
  to 
  the 
  volume 
  of 
  the 
  tube 
  contents 
  for 
  the 
  dis- 
  

   tance 
  between 
  the 
  last 
  level 
  and 
  the 
  level 
  of 
  the 
  water 
  in 
  the 
  aquarium. 
  

  

  The 
  stem 
  axis 
  of 
  the 
  plant 
  used 
  was 
  20 
  cm. 
  in 
  length 
  and 
  had 
  5 
  nodes 
  with 
  leaves. 
  

   The 
  cutting 
  bore 
  one 
  straight, 
  unbranched, 
  intact 
  root 
  14 
  cm. 
  in 
  length 
  and 
  clothed 
  

  

  .■Apparatus 
  for 
  measuring 
  root 
  absorption. 
  

  

  with 
  hairs. 
  The 
  water 
  in 
  the 
  tube 
  dropped 
  15 
  cm., 
  equal 
  to 
  a 
  vohnne 
  of 
  5 
  c. 
  c, 
  and 
  

   hence 
  the 
  root 
  absorbed 
  from 
  the 
  bottle 
  this 
  amount 
  of 
  water 
  in 
  twenty-four 
  hours. 
  

   This 
  test 
  was 
  repeated 
  the 
  following 
  day, 
  the 
  tube 
  receiving 
  the 
  5 
  c. 
  c. 
  necessary 
  to 
  

   make 
  the 
  levels 
  coincide 
  again, 
  and 
  the 
  same 
  result 
  was 
  obtained. 
  It 
  thus 
  appears 
  

   that 
  a 
  plant 
  of 
  this 
  description 
  at 
  a 
  temperature 
  of 
  20.5° 
  C. 
  absorbs 
  about 
  5 
  c. 
  c. 
  in 
  

   twenty-four 
  hours. 
  

  

  That 
  the 
  roots 
  do 
  absorb 
  water 
  is 
  therefore 
  considered 
  to 
  be 
  estab- 
  

   lished 
  by 
  two 
  direct 
  methods. 
  One 
  step 
  further 
  would 
  be 
  to 
  measure 
  

   the 
  water 
  excreted 
  by 
  the 
  stem 
  and 
  leaves. 
  Numerous 
  efforts 
  were 
  

   made 
  to 
  accomplish 
  this, 
  but 
  no 
  satisfactor}^ 
  apparatus 
  could 
  be 
  devised 
  

   that 
  would 
  secure 
  reliable 
  results. 
  

  

  