1029 
iHiinbei'  of  ganglion  cells  exoeeds  tlie  nnniber  of  axons  and  tliat  tliis 
excess  must  have  some  significanoe. 
From  the  silver-impregnated  series  we  obtaiii  an  indicalion  oftlie 
purpose  of  this  excess  in  tlie  iiiimber  of  cells.  We  find  that,  however 
intensivelj’  the  spinal  ganglia  are  impregnated  — especially  in  jonng 
anirnals  — theie  are,  all  the  same,  a number  of  cells  that  cainiot 
be  impregnated,  in  spite  of  the  fact  that  the  adjacent  cells  show  the 
most  splendid  neuro-tibril  sti’uctures.  It  is,  however,  not  alwajs  the 
srnallest  cells  that  cannot  be  impregnated,  bnt  a number  of  average- 
sized  ones  as  well,  while  others  of  the  srnallest  and  the  average- 
sized  ones  show  exceedingly  tine  impregnation.  The  question  why 
this  or  that  cell  is  not  impregnated  naturally  arises.  This  is  by  no 
means  the  tirst  time  that  attention  has  been  drawti  to  the  different 
powers  for  intensive  impregnation  shown  by  the  spinal  gangiion-cells. 
Even  in  his  work  on  “Zeil  substanz,  Kern  und  Zellteilung”  and  in 
the  presentation  volume  to  Heni.e,  Flemming  points  out  that  cells 
are  stained  to  different  degrees  of  intensity  by  the  same  colouring 
matter,  and  is  of  the  opinidn  that  this  is  due  to  greater  or  less 
density  in  the  colourable  tibres  of  which  the  protoplasni  is  eonstituted. 
Flesch,  Gitiss,  Koti.akevsky,  Koneff  and  Müller  ’)  and  others  have 
dealt  with  this  subject  more  oi  less  thoroughly.  Flesch  and  his 
pupils,  and  Mullek  among  others,  have  studied  the  capacity  for 
staining  possessed  by  the  ganglion  cells.  Koneff  states  that  the 
different  capacities  for  staining  are  not  connected  with  certain  species 
or  cells  with  special  morphological  characteristics.  The  cells  are  large 
and  small,  of  different  shapes,  and  some  of  them  are  distingnished 
by  their  chromatic  nucleus.  For  the  two  kinds  of  cells  — the 
strongly  and  the  weakly  stained  — this  author  suggests  the  names 
of  chromophila  and  chromophoba  ganglion  cells.  The  author  supposes 
that  some  of  these  different  cells  are  in  different  functional  stages 
and  others  are  developed  to  different  degrees.  Mtifii-ER  distinguishes 
a type  of  spinal  ganglion  cells  that  have,  among  other  characteristics, 
strongly  eosinophile  protoplasm  and  nuclei  rich  in  chromatin ; these 
cells  he  takes  to  be  developing  forms.  It  is  thus  not  only  in  silver 
impregnation,  but  also  with  ordinary  nuclei  and  protoplasmic 
impregnations  that  this  different  ititensity  in  the  impregnation  appears. 
With  regard  to  these  conditions  in  the  BiELSCHOwsKY-preparation,  thej' 
indicate  to  some  extent,  as  has  been  mentioned,  cells  with  elective 
neurotibril  impregnations  and  to  some  extent  cells  in  which  no  neurofibril 
b Muller,  Erik:  Studiën  über  die  Spinalganglien.  Biolog.  förening.  förhandl. 
Bd.  I.  1888 — 89.  Stockholm.  Other  statements  in  the  literature  that  touch  on  this 
subject  are  referred  to  here. 
