﻿I 
  

  

  170 
  BOTANICAL 
  GAZETTE. 
  [Julj' 
  

  

  this 
  reagent 
  is 
  especially 
  adapted 
  to 
  fixing 
  and 
  hardening 
  

   the 
  more 
  delicate 
  algae 
  without 
  structural 
  change. 
  The 
  

   plants 
  to 
  be 
  treated 
  are 
  placed 
  in 
  a 
  drop 
  of 
  water 
  on 
  a 
  slide, 
  

   and, 
  if 
  they 
  are 
  comparatively 
  large, 
  a 
  drop 
  of 
  the 
  one 
  per 
  

   cent, 
  solution 
  of 
  osmic 
  acid 
  is 
  added 
  and 
  the 
  whole 
  is 
  allowed 
  

   to 
  stand 
  for 
  perhaps 
  half 
  an 
  hour. 
  The 
  fluid 
  must, 
  however, 
  

   be 
  drained 
  away 
  from 
  the 
  plants 
  before 
  they 
  begin 
  to 
  show 
  

   the 
  browning 
  or 
  blackening 
  which 
  results 
  from 
  the 
  prolonged 
  

   action 
  of 
  the 
  acid. 
  In 
  the 
  case 
  of 
  very 
  small 
  or 
  unicellular 
  

   plants, 
  It 
  is 
  sufficient 
  to 
  invert 
  the 
  drop 
  of 
  water 
  containing 
  

   them 
  over 
  the 
  mouth 
  of 
  the 
  reagent 
  bottle, 
  since 
  the 
  fumes 
  

   of 
  the 
  acid 
  wall 
  produce 
  the 
  desired 
  effect 
  in 
  a 
  short 
  time. 
  

  

  Even 
  after 
  being 
  thus 
  hardened, 
  algje 
  can 
  not 
  safely 
  be 
  

   treated 
  with 
  glycerine 
  of 
  greater 
  strength 
  than 
  that 
  resulting 
  

   from 
  a 
  mixture 
  of 
  one 
  part 
  with 
  eight 
  or 
  ten 
  parts 
  of 
  water. 
  

   Ihey 
  should 
  be 
  allowed 
  to 
  stand, 
  protected 
  from 
  dust, 
  in 
  a 
  

   small 
  quanity 
  of 
  this 
  mixture, 
  which 
  gradually 
  decreases 
  in 
  

   volume 
  and 
  increases 
  in 
  density 
  until 
  it 
  nearly 
  reaches 
  that 
  

   Of 
  pure 
  glycerine, 
  by 
  the 
  spontaneous 
  evaporation 
  of 
  its 
  wa- 
  

   tei.^ 
  Ihe 
  concentration 
  is 
  so 
  slow 
  that 
  not 
  the 
  slightest 
  

   snrinkmg 
  ordinarily 
  occurs 
  in 
  plants 
  first 
  fixed 
  with 
  osmic 
  

  

  acid. 
  A 
  couple 
  of 
  days 
  is 
  usually 
  required 
  for 
  its 
  accom- 
  

   plishment, 
  -r 
  ^ 
  

  

  o^ 
  i"^*^^]" 
  ^'"'^'"^"g 
  aweiy 
  the 
  excess 
  of 
  glycerine, 
  one 
  may 
  

   rpn/' 
  ^;?,P.°f 
  glycerine 
  jelly, 
  warmed 
  /ust 
  sufficiently 
  to 
  

   renclei 
  it 
  fiuid, 
  and 
  then 
  cover 
  at 
  once.' 
  Air 
  bubbles 
  are 
  

  

  vvnr^^f 
  ^^cr?''^^'^ 
  '^ 
  ^°^1^ 
  ^^''^^ 
  «nd 
  cover 
  glass 
  are 
  gently 
  

   di..^ 
  V 
  ^^^ 
  carefully 
  prepared 
  bv 
  this 
  method 
  preserve 
  

   details 
  of 
  structure 
  and 
  the 
  natural 
  appearance 
  of 
  the 
  plants 
  

  

  7rlhl\-'^ 
  completeness 
  and 
  show 
  no 
  change 
  after 
  a 
  consid- 
  

  

  ei 
  aWe 
  time, 
  as 
  the 
  writer 
  can 
  testify. 
  

  

  i^esides 
  applying 
  this 
  process 
  to" 
  the 
  preservation 
  of 
  fresh- 
  

   ■ei 
  algae, 
  for 
  which 
  it 
  was 
  especially 
  recommended 
  by 
  Dr. 
  

  

  water 
  

  

  Klpin 
  T 
  k 
  ""-'-" 
  ^<- 
  vvas 
  especially 
  recommencien 
  in 
  ^^^ 
  

  

  other\Lu\^ 
  ""^ 
  opportunity 
  to 
  test 
  its 
  applicability 
  to 
  

   Wood's 
  HI? 
  ^^^i"'- 
  ^' 
  '^'^ 
  "^^^'"^ 
  biological 
  laboratory 
  at 
  

   dems 
  in?nf 
  ' 
  ■'''•' 
  ^" 
  ^^^g"«^ 
  l^^^t, 
  it 
  wa"s 
  used 
  by 
  the 
  stu- 
  

   and 
  wi^h 
  W,'''^ 
  '"^ 
  Pr^P'^ring 
  all 
  their 
  slides 
  of 
  marine 
  alg^e, 
  

   were 
  mnnT? 
  '"J"^^''- 
  Members 
  of 
  all 
  the 
  chief 
  grouF 
  

   careful 
  s^^5 
  1^, 
  '''''^ 
  ^""^^^"^ 
  results. 
  Some 
  of 
  my 
  most 
  

   W 
  rj' 
  1";:^ 
  '^P^'^ 
  that 
  all, 
  or 
  most 
  of 
  their 
  preparations 
  

   cert'inTv 
  vl 
  7^^^"^^^ 
  i" 
  every 
  respect, 
  and 
  they 
  were 
  

   '; 
  'h""J? 
  ' 
  ^^'^^^" 
  ^^^«h, 
  the 
  best 
  I 
  have 
  ever 
  een. 
  The 
  alga 
  

  

  altered 
  ' 
  '''''' 
  ''' 
  ^ 
  ^^''' 
  exceptional 
  species, 
  not 
  at 
  all 
  

  

  