﻿vi 
  

  

  and 
  English, 
  in 
  which 
  he 
  discusses 
  against 
  Mulder 
  the 
  value 
  of 
  the 
  com- 
  

   bined 
  action 
  of 
  sulphuric 
  acid 
  and 
  iodine 
  as 
  a 
  colour-test 
  for 
  cellulose, 
  his 
  

   object 
  being 
  to 
  insist 
  on 
  that 
  substance 
  being 
  regarded 
  as 
  the 
  basis 
  of 
  all 
  

   vegetable 
  membrane. 
  

  

  In 
  1850 
  he 
  experimented 
  with 
  Hoffman 
  on 
  the 
  function 
  of 
  vessels, 
  but 
  

   with 
  contradictory 
  results. 
  

  

  He 
  pointed 
  out 
  in 
  1851 
  that 
  the 
  formation 
  of 
  chlorophyl 
  is 
  in 
  intimate 
  

   relation 
  with 
  protoplasm, 
  portions 
  of 
  which 
  it 
  tinges 
  in 
  making 
  its 
  first 
  

   appearance. 
  

  

  In 
  1852 
  he 
  published 
  a 
  short 
  paper 
  on 
  the 
  grape-mildew. 
  

  

  In 
  1855 
  his 
  researches 
  on 
  the 
  structure 
  of 
  " 
  liber 
  " 
  brought 
  out 
  some 
  

   entirely 
  new 
  facts. 
  He 
  had 
  already 
  been 
  the 
  first 
  (in 
  1836) 
  to 
  examine 
  

   bast- 
  cells 
  with 
  care. 
  He 
  pointed 
  out 
  that 
  bast-cells 
  were 
  far 
  from 
  being 
  

   so 
  exclusive 
  a 
  constituent 
  of 
  the 
  liber 
  as 
  had 
  been 
  supposed, 
  and 
  that 
  they 
  

   were 
  often 
  accompanied, 
  or 
  even 
  entirely 
  replaced, 
  by 
  the 
  " 
  Gritterzellen." 
  

   His 
  study 
  of 
  the 
  causes 
  of 
  the 
  opening 
  and 
  closing 
  of 
  stomata 
  in 
  1856 
  

   was 
  the 
  first 
  systematic 
  examination 
  which 
  the 
  question 
  had 
  received. 
  

   It 
  cleared 
  up 
  the 
  apparent 
  contradiction 
  of 
  the 
  results 
  obtained 
  by 
  Sir 
  

   Joseph 
  Banks 
  on 
  the 
  one 
  hand, 
  and 
  Moldenhawer 
  on 
  the 
  other. 
  

  

  In 
  1857 
  Yon 
  Mohl 
  discovered 
  the 
  extremely 
  curious 
  fact 
  that 
  the 
  

   substance 
  known 
  as 
  " 
  gum 
  tragacanth 
  " 
  is 
  produced 
  by 
  the 
  altera- 
  

   tion 
  of 
  the 
  cells 
  of 
  the 
  pith 
  and 
  medullary 
  rays 
  of 
  various 
  species 
  of 
  

   Astragalus. 
  

  

  Passing 
  over 
  contributions 
  of 
  minor 
  importance, 
  Yon 
  Mohl 
  published 
  

   in 
  1870 
  a 
  short 
  discussion 
  of 
  the 
  passages 
  in 
  the 
  writings 
  of 
  Linnaeus 
  

   which 
  have 
  been 
  held 
  to 
  indicate 
  a 
  foreshadowing 
  in 
  his 
  mind 
  of 
  the 
  theory 
  

   of 
  descent. 
  

  

  The 
  last 
  paper 
  which 
  appeared 
  in 
  Yon 
  Mold's 
  lifetime 
  was 
  on 
  an 
  

   extremely 
  suggestive 
  subject, 
  the 
  morphology 
  of 
  the 
  foliar 
  organs 
  of 
  the 
  

   umbrella-pine 
  of 
  Japan 
  (Sciadopitys). 
  The 
  microscopic 
  structure 
  of 
  these 
  

   organs 
  led 
  him 
  to 
  compare 
  them 
  to 
  two 
  consolidated 
  leaves 
  with 
  the 
  

   organic 
  underside 
  turned 
  uppermost. 
  They 
  therefore 
  suggested 
  an 
  ana- 
  

   logy 
  with 
  the 
  squama? 
  fructiferce 
  of 
  Coniferae 
  generally, 
  upon 
  the 
  true 
  

   nature 
  of 
  which 
  they 
  have 
  therefore 
  been 
  held 
  to 
  throw 
  an 
  important 
  

   light. 
  

  

  In 
  1850 
  Yon 
  Mohl 
  published 
  a 
  small 
  work 
  with 
  the 
  title 
  " 
  Die 
  vege- 
  

   tabilische 
  Zelle," 
  which 
  weaves 
  the 
  results 
  of 
  a 
  great 
  deal 
  of 
  what 
  he 
  had 
  

   written 
  in 
  scattered 
  memoirs 
  into 
  a 
  continuous 
  whole. 
  It 
  was 
  translated 
  

   into 
  English 
  by 
  Prof. 
  Henfrey 
  in 
  1852. 
  

  

  t 
  Yon 
  Mohl 
  felt 
  the 
  greatest 
  interest 
  in 
  improving 
  the 
  means 
  of 
  histo- 
  

   logical 
  and 
  anatomical 
  research, 
  and 
  wrote 
  several 
  papers 
  on 
  the 
  con- 
  

   struction 
  and 
  use 
  of 
  optical 
  instruments, 
  and 
  in 
  1846 
  published 
  a 
  book 
  

   on 
  micrography. 
  

  

  Dr. 
  Robert 
  Edmokd 
  G-eant 
  was 
  the 
  seventh 
  son 
  of 
  Alexander 
  Grant, 
  

   Esq., 
  Writer 
  to 
  the 
  Signet. 
  He 
  was 
  born 
  in 
  his 
  father's 
  house 
  in 
  Argyle 
  

  

  