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  PROCEEDINGS 
  OE 
  

  

  THE 
  ROYAL 
  SOCIETY. 
  

  

  Section 
  B. 
  — 
  Biological 
  Sciences. 
  

  

  On 
  the 
  Occurrence 
  of 
  Multinucleate 
  Cells 
  in 
  Vegetative 
  Tissues. 
  

  

  By 
  Rudolf 
  Beer, 
  B.Sc, 
  F.L.S., 
  and 
  Agnes 
  Arber, 
  D.Sc, 
  F.L.S., 
  Fellow 
  of 
  

   Newnham 
  College, 
  Cambridge. 
  

  

  (Communicated 
  by 
  Prof. 
  J. 
  Bretland 
  Farmer, 
  F.R.S. 
  — 
  Received 
  May 
  23, 
  1918.) 
  

  

  (Plate 
  1.) 
  

  

  Historical 
  Introduction. 
  

  

  The 
  typical 
  animal 
  or 
  vegetable 
  cell 
  is 
  now 
  universally 
  held 
  to 
  consist 
  of 
  a 
  

   protoplasmic 
  body, 
  either 
  naked 
  or 
  enclosed 
  in 
  a 
  cell 
  membrane 
  and 
  con- 
  

   taining, 
  as 
  its 
  most 
  essential 
  constituent, 
  a 
  single 
  nucleus. 
  This 
  view 
  as 
  to 
  

   the 
  uninucleate 
  character 
  of 
  the 
  vegetable 
  cell 
  was 
  first 
  definitely 
  formulated 
  

   by 
  Nageli 
  in 
  1844. 
  A 
  few 
  well-defined 
  exceptions 
  to 
  this 
  rule, 
  such 
  as 
  pollen 
  

   grains, 
  embryo 
  sacs, 
  etc., 
  were 
  recognised 
  by 
  Nageli 
  himself, 
  and 
  during 
  the 
  

   three-quarters 
  of 
  a 
  century 
  which 
  has 
  elapsed 
  since 
  the 
  publication 
  of 
  his 
  

   work, 
  several 
  other 
  instances 
  of 
  multinucleate 
  cells 
  have 
  been 
  observed 
  by 
  

   Schmitz, 
  Treub, 
  Johow, 
  Strasburger, 
  Grant, 
  and 
  others. 
  These 
  cases, 
  in 
  which 
  

   a 
  plurality 
  of 
  nuclei 
  was 
  seen 
  to 
  occur 
  in 
  the 
  cell, 
  were 
  however 
  regarded 
  

   as 
  isolated 
  exceptions 
  to 
  an 
  otherwise 
  universal 
  rule, 
  and 
  of 
  no 
  general 
  

   significance. 
  

  

  In 
  1914 
  Dr. 
  McLean* 
  observed 
  cells 
  with 
  more 
  that 
  one 
  nucleus 
  in 
  the 
  

   tissues 
  of 
  certain 
  water 
  plants, 
  while 
  in 
  1915 
  Miss 
  Prankerdf 
  published 
  an 
  

   account 
  of 
  her 
  researches 
  on 
  multinucleate 
  cells. 
  She 
  recorded 
  the 
  occur- 
  

   rence 
  of 
  multinucleate 
  cells 
  in 
  36 
  species 
  of 
  plants 
  " 
  widely 
  separated 
  in 
  

  

  * 
  McLean, 
  E. 
  C, 
  " 
  Amitosis 
  in 
  the 
  Parenchyma 
  of 
  Water-Plants," 
  ' 
  Proc. 
  Camb. 
  

   Phil. 
  Soc., 
  ! 
  vol. 
  17, 
  pp. 
  380-382 
  (1914), 
  1 
  text-fig. 
  

  

  t 
  Prankerd, 
  T. 
  L., 
  "Notes 
  on 
  the 
  Occurrence 
  of 
  Multinucleate 
  Cells," 
  'Ann. 
  Bot.,' 
  

   vol. 
  29, 
  pp. 
  599-604 
  (1915), 
  8 
  text-figs. 
  

  

  VOL. 
  XCI. 
  — 
  B. 
  B 
  

  

  