﻿ii 
  

  

  of 
  Von 
  Mold's 
  is 
  not 
  the 
  solid 
  foundation 
  of 
  our 
  present 
  knowledge. 
  The 
  

   Catalogue 
  of 
  Scientific 
  Papers 
  of 
  the 
  Eoyal 
  Society 
  enumerates 
  78 
  of 
  

   his 
  papers 
  — 
  not 
  including 
  "various 
  dissertations, 
  some 
  of 
  which, 
  along 
  with 
  

   a 
  selection 
  of 
  the 
  more 
  important 
  of 
  his 
  papers, 
  were 
  in 
  1845 
  collected 
  and 
  

   published 
  in 
  a 
  quarto 
  volume, 
  under 
  the 
  title 
  of 
  " 
  Vermischte 
  Schriften." 
  

   The 
  list 
  of 
  his 
  publications 
  which 
  accompanies 
  the 
  memoir 
  in 
  the 
  

   ' 
  Eotanische 
  Zeitung 
  ' 
  gives 
  the 
  titles 
  of 
  no 
  less 
  than 
  90. 
  Nor 
  were 
  his 
  

   own 
  labours 
  the 
  only 
  way 
  in 
  which 
  he 
  contributed 
  to 
  the 
  advancement 
  of 
  

   our 
  knowledge 
  of 
  the 
  minute 
  anatomy 
  of 
  plants. 
  In 
  1843 
  he 
  commenced, 
  

   in 
  conjunction 
  with 
  Schlechtendal, 
  the 
  'Botanische 
  Zeitung,' 
  a 
  small 
  

   quarto 
  weekly 
  periodical 
  of 
  eight 
  pages, 
  occasionally 
  illustrated 
  with 
  

   plates, 
  which 
  he 
  continued 
  to 
  edit 
  till 
  the 
  time 
  of 
  his 
  death. 
  The 
  

   volumes 
  of 
  this 
  journal 
  chronicle, 
  year 
  by 
  year, 
  the 
  gradual 
  development 
  

   of 
  the 
  microscopic 
  study 
  of 
  plants, 
  a 
  field 
  in 
  which 
  (doubtless 
  in 
  no 
  small 
  

   degree 
  owing 
  to 
  the 
  example 
  of 
  Yon 
  Mohl) 
  German 
  science 
  has 
  reaped 
  a 
  

   more 
  abundant 
  harvest 
  than 
  that 
  of 
  other 
  nations. 
  No 
  one 
  can 
  fail 
  to 
  

   be 
  struck 
  with 
  the 
  thorough 
  character 
  of 
  Yon 
  Mohl's 
  scientific 
  work. 
  His 
  

   energies 
  were 
  always 
  ready 
  to 
  turn 
  themselves 
  to 
  any 
  part 
  of 
  his 
  subject 
  

   where 
  facts 
  seemed 
  to 
  need 
  investigation, 
  or 
  the 
  results 
  of 
  others 
  to 
  

   challenge 
  reexamination 
  or 
  criticism. 
  His 
  papers 
  are, 
  in 
  their 
  way, 
  

   models 
  of 
  " 
  contributions 
  to 
  knowledge." 
  Except 
  when 
  they 
  are 
  controver- 
  

   sial, 
  they 
  always 
  commence 
  with 
  a 
  careful 
  history 
  and 
  estimate 
  of 
  the 
  work 
  

   of 
  previous 
  investigators 
  of 
  the 
  particular 
  subject 
  under 
  consideration. 
  

  

  Yon 
  Mohl's 
  first 
  publication 
  in 
  1827 
  was 
  a 
  prize 
  thesis 
  on 
  the 
  structure 
  

   of 
  climbing 
  plants, 
  in 
  which 
  he 
  endeavoured 
  to 
  show 
  that 
  the 
  stems 
  have 
  

   a 
  dull 
  kind 
  of 
  irritability, 
  so 
  that 
  they 
  bend 
  towards 
  any 
  object 
  which 
  

   they 
  touch. 
  This 
  explanation 
  has 
  given 
  place 
  to 
  a 
  better 
  knowledge 
  of 
  

   the 
  phenomena 
  ; 
  but 
  Mr. 
  Darwin, 
  to 
  whom 
  that 
  service 
  to 
  science 
  is 
  

   largely 
  due, 
  bears 
  witness 
  to 
  the 
  prima 
  facie 
  probability 
  of 
  Yon 
  Mohl's 
  

   view 
  (Journ. 
  Linn. 
  Soc, 
  Bot. 
  vol. 
  ix. 
  p. 
  10). 
  His 
  inaugural 
  dissertation 
  in 
  

   1828 
  (already 
  alluded 
  to) 
  gave 
  the 
  first 
  account 
  of 
  the 
  true 
  structure 
  of 
  

   the 
  dots 
  or 
  " 
  pores 
  " 
  frequently 
  met 
  with 
  in 
  the 
  walls 
  of 
  cells 
  (' 
  Ueber 
  

   die 
  Poren 
  des 
  Pflanzenzellgewebes 
  '). 
  He 
  showed 
  that 
  they 
  were 
  thinner 
  

   portions 
  of 
  the 
  cell-membrane. 
  

  

  In 
  1831 
  Yon 
  Mohl, 
  as 
  already 
  mentioned, 
  contributed 
  to 
  the 
  ' 
  Historia 
  

   Naturalis 
  Palmarum 
  ' 
  of 
  Yon 
  Martius 
  an 
  elaborate 
  account 
  in 
  Latin 
  of 
  

   the 
  structure 
  of 
  the 
  stems 
  and 
  roots 
  of 
  palms, 
  under 
  the 
  title 
  " 
  De 
  Struc- 
  

   tura 
  Palmarum." 
  This 
  was 
  republished 
  in 
  German 
  in 
  his 
  ' 
  Vermischte 
  

   Schriften' 
  in 
  1845, 
  and 
  was 
  translated 
  for 
  the 
  Eay 
  Society 
  in 
  1849 
  by 
  

   Prof. 
  Henfrey. 
  Von 
  Mohl 
  gave 
  the 
  final 
  blow 
  to 
  the 
  theory 
  of 
  the 
  internal 
  

   growth 
  of 
  monocotyledonous 
  stems 
  first 
  propounded 
  by 
  Eesfontaines, 
  and 
  

   upon 
  which 
  I)e 
  Candolle 
  had 
  founded 
  the 
  division 
  of 
  vascular 
  plants 
  into 
  

   Exogens 
  and 
  Endogens. 
  In 
  this 
  memoir 
  he 
  appears 
  to 
  have 
  first 
  

   described 
  the 
  origin 
  of 
  ducts 
  from 
  rows 
  of 
  closed 
  cells, 
  a 
  point 
  which 
  le 
  

   further 
  developed 
  in 
  the 
  following 
  year 
  in 
  a 
  paper, 
  " 
  Ueber 
  den 
  Bau 
  der 
  

   porosen 
  Gefa'sse. 
  

  

  