﻿V 
  

  

  final 
  account 
  of 
  the 
  matter. 
  In 
  the 
  same 
  year 
  he 
  published 
  his 
  investi- 
  

   gations 
  on 
  the 
  cuticle 
  of 
  plants, 
  which 
  he 
  demonstrated 
  to 
  be 
  organi- 
  

   cally 
  derived 
  from 
  the 
  epidermic 
  cells. 
  He 
  further 
  supported 
  this 
  view- 
  

   in 
  papers 
  published 
  in 
  1847 
  and 
  1849. 
  

  

  Von 
  Molil's 
  researches 
  in 
  1843 
  ('Ueber 
  denMilchsaft 
  und 
  seine 
  Bewe- 
  

   gung 
  ') 
  demolished 
  Schultz's 
  analogy 
  of 
  latex 
  to 
  blood. 
  They 
  were 
  pub- 
  

   lished 
  in 
  the 
  ' 
  Botanische 
  Zeitung,' 
  which 
  was 
  started 
  in 
  this 
  year. 
  

  

  In 
  1844 
  Yon 
  Mohl 
  maintained, 
  against 
  the 
  theory 
  of 
  Dupetit-Thouars, 
  

   the 
  dependence 
  of 
  the 
  growth 
  of 
  Dicotyledons 
  on 
  the 
  physiological 
  activity 
  

   of 
  leaves. 
  The 
  same 
  year 
  he 
  published 
  his 
  remarks 
  on 
  the 
  structure 
  

   of 
  the 
  vegetable 
  cell, 
  which 
  for 
  a 
  long 
  time 
  immensely 
  influenced 
  the 
  

   course 
  of 
  vegetable 
  histology. 
  He 
  regarded 
  the 
  cell-wall 
  as 
  generally 
  

   composed 
  of 
  a 
  primary 
  external 
  imperforate 
  membrane, 
  and 
  a 
  secondary 
  

   one 
  usually 
  perforated 
  with 
  apertures. 
  This 
  he 
  supposed 
  to 
  be 
  lined 
  

   by 
  a 
  third 
  membrane, 
  " 
  Primordialschlauch," 
  the 
  primordial 
  utricle 
  of 
  

   English 
  writers. 
  " 
  This 
  membrane 
  forms 
  a 
  perfectly 
  closed, 
  cell-like, 
  thin- 
  

   walled 
  vesicle, 
  which 
  in 
  the 
  fresh 
  plant 
  is 
  closely 
  applied 
  to 
  the 
  inner 
  

   wall 
  of 
  the 
  cell, 
  and 
  therefore 
  escapes 
  observation 
  ; 
  while 
  in 
  specimens 
  

   which 
  have 
  been 
  preserved 
  in 
  spirit 
  it 
  is 
  contracted, 
  and 
  more 
  or 
  less 
  

   detached 
  from 
  the 
  wall 
  of 
  the 
  cell." 
  

  

  In 
  1845 
  Yon 
  Mohl 
  published 
  a 
  memoir 
  on 
  the 
  Flora 
  of 
  Wurtemberg. 
  

   It 
  is 
  interesting 
  to 
  find 
  a 
  great 
  physiological 
  botanist 
  engaged 
  in 
  work 
  of 
  

   this 
  kind, 
  which 
  it 
  is 
  rather 
  the 
  fashion 
  at 
  present 
  to 
  depreciate. 
  Yon 
  

   Mohl 
  enters 
  at 
  some 
  length 
  into 
  the 
  causes 
  which 
  influence 
  the 
  local 
  dis- 
  

   tribution 
  of 
  plants 
  ; 
  and 
  it 
  is 
  in 
  regard 
  to 
  points 
  of 
  this 
  kind 
  that 
  he 
  

   attaches 
  scientific 
  importance 
  to 
  local 
  floras. 
  An 
  examination 
  of 
  a 
  mon- 
  

   strous 
  state 
  of 
  Poa 
  alpina 
  led 
  him 
  to 
  the 
  now 
  generally 
  received 
  opinion 
  

   that 
  the 
  lower 
  floral 
  glume 
  of 
  grasses 
  is 
  not 
  a 
  perigonial 
  leaf 
  but 
  a 
  bract. 
  

   To 
  the 
  same 
  year 
  belongs 
  a 
  paper 
  on 
  the 
  penetration 
  of 
  cuticle 
  into 
  

   stomata. 
  

  

  Yon 
  Mohl's 
  paper, 
  " 
  Ueber 
  die 
  Saftbewegungen 
  im 
  Inneren 
  der 
  Zellen," 
  

   published 
  in 
  1846 
  (Bot. 
  Zeit. 
  p. 
  73), 
  has 
  been 
  the 
  starting-point 
  of 
  all 
  

   modern 
  views 
  about 
  the 
  vegetable 
  cell. 
  He 
  first 
  described 
  accurately 
  the 
  

   " 
  opaque 
  viscid 
  fluid 
  of 
  a 
  white 
  colour, 
  having 
  granules 
  intermingled 
  with 
  

   it, 
  which 
  fluid 
  I. 
  call 
  protoplasm.' 
  1 
  '' 
  He 
  observed 
  the 
  vacuolization 
  of 
  the 
  pro- 
  

   toplasm 
  until 
  it 
  forms 
  a 
  mere 
  network. 
  He 
  described 
  the 
  motion 
  which 
  

   takes 
  place 
  in 
  the 
  filament 
  of 
  the 
  network, 
  " 
  or 
  perhaps 
  now 
  first 
  becomes 
  

   visible," 
  and 
  he 
  measured 
  its 
  rate. 
  Schleiden 
  gave 
  the 
  theory 
  its 
  finishing 
  

   touch 
  in 
  the 
  third 
  edition 
  of 
  his 
  ' 
  Principles 
  ' 
  (1849), 
  by 
  identifying 
  Mohl's 
  

   primordial 
  utricle 
  and 
  circulating 
  fluid. 
  

  

  In 
  1847 
  Yon 
  Mohl 
  confirmed 
  the 
  researches 
  of 
  Amici 
  (for 
  whom 
  he 
  

   had 
  a 
  high 
  regard) 
  on 
  the 
  impregnation 
  of 
  Orchideae, 
  which, 
  in 
  his 
  judg- 
  

   ment, 
  made 
  an 
  end 
  of 
  Schleiden's 
  theory 
  as 
  to 
  the 
  origin 
  of 
  the 
  embryo 
  

   in 
  Phanerogams, 
  although 
  the 
  controversy 
  was 
  carried 
  on 
  for 
  some 
  time 
  

   longer 
  by 
  Hofmeister, 
  Tulasne, 
  Schacht, 
  and 
  Eadlkofer. 
  He 
  also 
  pub- 
  

   lished 
  an 
  elaborate 
  memoir, 
  which 
  has 
  been 
  translated 
  into 
  both 
  French 
  

  

  