1 ü4y 
Amitotic  division. 
Most  investigators  believe,  witli  Ff^emming,  tliat  initotic  cell  divisioJi 
is  tlie  only  way  iii  wliich  a iiew  growth  in  a healtliy  body  naii 
take  place.  And  it  is  genei-ally  adinitted  that  amitotic  cell  division 
occurs  only  in  pathological  tissues  and,  apart  froin  this,  only  in 
cells  tbat  liave  a very  short  life.  As  bas  been  pointed  out  above, 
the  nerve  cells  are  generally  adraitted  to  have  a life  equal  in  length 
to  that  of  the  individual;  it  is  therefore  obvious  that  any  idea  of 
an-increase  in  these  by  amitotic  division  must  be  out  of  the  question. 
And  I must  myself  confess  that  the  idea  of  the  pcrmanence  and 
high  positioji  of  the  neurones  among  the  cells  in  general  has  become 
so  deeply  rooted  through  studying  handbooks  of  medicine  as  well  as 
the  majority  of  special  treatises  on  this  subject  that  it  is  really 
difficnlt  to  get  accustomed  to  the  idea  that  there  may  be  another 
possibility  for  the  increase  in  the  nerve-cells  than  rnitotic  division. 
If,  however,  one  comes  quite  freely,  as  I did,  to  the  piobleni  of 
explaining  the  actually  existing  increase  in  the  nerve-fibres  during 
the  whole  post-embryonic  developmenl,  and  linds  that  this  explanation 
has  to  be  sought  in  an  increase  in  the  number  of  the  neurones  and 
not  in  a cleavage  of  the  axons  — and  this  at  the  same  time  as  one 
tinds  signs  of  how  a large  number  of  the  nerve  cells  ai-e  degene- 
rating  and  dying  away,  then  of  course  the  new  formation  of  ganglion 
cells,  even  after  mitoses  no  longer  occur  in  these  regions,  must  be 
considerable.  There  are  also  in  the  central  nervous  system,  as  will 
be  described  in  more  detail  belovv,  appearances  that  seem  to  indicate 
that  amitotic  division  of  young  cells  really  takes  place  there.  Obser- 
vations  pointing  in  this  direction  have  already  been  made  and 
described  in  literature,  although  this  information  seems  to  have 
attracted  but  little  attention. 
Rohde ‘)  described  in  1896  how  ganglion  cells  in  invertebrates 
increase  by  amitotic  division.  R.  distinguishes  four  different  types 
of  such  a division  in  these  animals.  As  invertebrates  have  not  been 
the  object  of  rny  investigations  in  this  matter,  I cannot  criticize 
R’s  statements,  although  some  of  them  seem  somewhat  strange. 
Paladino^)  (1914)  describes  amitotic  division  of  cells  in  the  central 
nervous  system  of  vertebrates.  P.  States  that  the  neurones  degenerate 
and  perish,  and  in  connection  with  this  there  is  a new  development  of 
nerve  elements.  There  are  good  reasons  for  believing  that  this 
')  Rohde,  1.  c. 
*)  Paladino,  1.  c. 
