Verslagen  der  Afdeeling  Natuurk.  Dl,  XXVII.  A",  1918  19 
EXPLANATION  OF  FIGURES. 
Figures  1,  2,  4,  5,  6,  9.  10,  11,  22,  23,  24  and  25  are  drawn  after  magnifying  wilh 
Leitz  immers,  h-:  and  ncul.  4 and  using  Reichert’s  drawing  apparatus. 
Figures  3,  7,  8,  12  and  26  are  drawn  after  magnifying  with  Zeiss  apochr.  immers.; 
2 mm.  Apart.  1.3  and  Comp.  ocul.  N".  6,  with  the  help  of  Abbe's  drawing  apparatus'. 
Figures  13,  14,  15,  16,  17,  18,  19,  20  and  21  are  drawn  after  magnifying  with  Zeiss 
Apochr.  imm.,  2 mm.  Apart.  1.3  and  Comp.  ocul.  N".  12,  with  the  help  of  Lf.it/.’s 
drawing  appara(us. 
Fig.  1.  Repr.  -la.  Gangl.  spin.  (Fix.  Flemming  staining  Jhtx  and  Eos,  } of  a 17days' 
old  dog.  (t.  Ganglion  cell  wilh  division  of  the  nucleolus  just  starled,  b.  Nucleus  dividing 
amitotically.  This  small  distinct  collum-formalion  between  the  nuclei  is  very  rare. 
Fig.  2.  Repr.  %.  Gangl.  spin.  (Fix.  and  staining  the  same  as  the  preceding)  from  the 
same  section  series  as  in  fig.  1.  a.  Ganglion  cell  dividing  amitotically.  b.  Ganglion  cell 
in  which  the  nucleus  has  two  nucleoli. 
Fig.  3.  Repr.  Gangl.  spin.  (Silver-impregnated  according  to  the  Bielschowsky- 
method  with  my  own  modifications)  of  a six  days’  old  dog.  a.  Ganglion  cell  dividing 
amitotically.  b.  Ganglion  cell  with  the  beginning  of  amitotic  division  of  the  nucleus. 
Fig.  4.  Repr.  -k.  Gangl.  spin.  (Impr.  as  in  fig.  3)  of  a sixly  days’  old  dog.  t;.  Colony 
of  apolar  cells.  Between  the  three  cells  in  the  middle  there  are  bridges  of  protoplasm. 
Fig.  5.  Repr.  -/;i.  Gangl.  spin.  (Fix.  and  staining  as  in  fig.  1)  of  a 17  days’  old  dog 
The  ganglion  cell  on  the  left  imitates  a milosis.  The  milosis  in  realily  belongs  to  a 
capsular  cell. 
Fig.  6.  Repr.  V;i.  Gangl.  spin.  (Fix.  and  stain.  as  in  fig.  1)  of  a 17  days’  old  dog. 
The  mitoses  in  the  capsular  cells  or  in  cells  subcapsularly  situated.  which  have  a tendency 
to  become  ganglion  cells  (?). 
Fig.  7.  Repr.  V--  Gangl.  spin.  (Fix.  and  stain.  as  in  fig.  1)  of  a 17  days'  old  dog. 
Mitosis  in  the  capsular  cell. 
Fig.  8.  Repr.  Gangl.  spin.  (Fix.  and  stain.  as  in  fig.  1)  of  a 17  days’  old  dog. 
Mitosis  in  a very  young  ganglion  cell. 
Fig.  9.  Repr.  Vi.  Spinal  cord.  (Fix.  and  stain.  as  in  fig.  1)  of  a 24  days’  old  Mus 
musculus  var.  albus.  a.  Mitosis.  b.  Amitosis  in  a young  nerve  cell. 
Fig.  10.  Repr.  Va.  Spinal  cord  (Fix  and  stain.  as  in  fig.  1)  of  a 24  days’  old  Mus 
mtésculus  var.  albus.  Syncytium  or  plasmodium  of  young  nerve  cells. 
Fig.  11.  Repr.  Vi.  Spinal  cord  (Fix.  and  stain.  as  in  fig.  1)  of  a 24  days’  old  Mus 
musculus  var.  albus.  Mitosis  in  the  nerve  cells. 
Fig.  12.  Repr.  %.  Spinal  ganglion  (Impragn.  as  in  fig.  3)  of  a 17  days’  old  dog. 
Bipolar  ganglion  cell. 
Fig.  13.  Repr. -/3.  Spinal  cord  (Fix.  and  stain.  as  in  fig.  1 ) of  a full-grown  M.  musc.  v.  alb. 
An  example  of  fairly  frequently  occurring  indentations  on  nuclei  of  nerve  cells:  in 
my  opinion  these  indentations  have  very  probably  no  connection  with  amitotic  division. 
Fig.  14.  Repr.  Va.  Spinal  cord  (Fix.  and  stain.  as  in  fig.  1)  of  a ten  days’  old  Aïus 
musculus  V.  albus.  An  example  of  a stage  in  amitotic (?J  division  in  which  the  nuclei 
are  quite  separated  but  the  protoplasmic  body  is  not  quile  divided. 
Fig.  15.  Repr.  Va.  Spinal  cord  (Fix.  and  stain.  as  fig.  1^  of  a ten  days’  old  Mus 
musc.  var.  albus.  Cell  plasmodium  or  syncytium,  situated  just  ventrally  of  the  canalis 
centralis. 
Fig.  16.  Repr.  Va.  Spinal  cord  (Fix.  and  stain.  as  in  fig.  1)  of  a ten  days’  old  Mus 
musculus  V.  albus.  An  example  of  a cell  at  an  early  stage  of  amitotic  division. 
Fig.  17.  Repr.  Va.  Spinal  cord  (as  in  the  preceding  figure).  An  example  of  direct 
division  of  the  nucleoli  and  a somewhat  later  stage  than  in  the  proceding  figure  of  direct 
division  of  the  cell  in  its  entirety. 
Fig.  18.  Repr.  Va.  Same  material  as  in  the  preceding  figure.  Young  ganglion  cells 
(neuroblast)  engaged  in  direct  division. 
Fig.  19.  Repr.  Va.  Same  material  as  in  the  preceding  figure.  A cell  engaged  in  direct 
division. 
Fig.  20.  Repr.  Vi.  Spinal  cord  (Fix.  and  stain.  as  in  fig.  1)  of  a 24  days’  old  M. 
musc.  V.  alb.  A young  nerve-cell  in  a far  advanced  stage  of  direct  division. 
Fig.  21.  Repr.  Va.  Same  material  as  in  fig.  16.  Young  nerve  cells  from  the  base  of 
the  dorsal  horn  in  a very  far  advanced  direct  division  into  four. 
Figs.  22,  23  and  24  are  probable  and  figs.  25  and  26  certain  figures  of  growth  in 
the  roots  of  the  seventh  lumbar  nerve  in  a 17  days’  old  dog.  The  material  is  silver- 
impregnated  according  to  my  modifications  of  the  BiELSCHOWSKY-method. 
