1043 
but  the  iieuro-tibrils  appear  exceedingly  distiiict.  One  may  tliiis 
postidate  tliat  if  processes  of  the  cells  in  ibis  colony  had  really 
exiöted,  tliey  wonld  also  have  clearly  appeared  in  llie  sections.  That 
these  cells  are  likewise  at  an  early  stage  in  their  development  is 
indicated,  in  addilion,  by  the  tact  that  there  are  evident  bridges  of 
protoplasm  between  some  of  them.  In  this  seiles  of  sections  there 
are,  however,  colonies  of  cells  wliich,  as  far  as  one  can  jndge,  are  at 
later  stages  in  their  development  — in  these  the  different  cells  have 
processes,  there  are  no  bridges  of  protoplasm  between  them,  and 
the  fntnre  capsules  of  the  separate  cells  exhibit  the  first  tracés  of 
their  development.  Iir  the  cells  of  some  of  the  coloides  found  in  the 
3,5  year  old  dog  I have  been  able  to  show  processes  — there  were 
also  signs  sliowing  that  these  colonies  were  at  a later  stage  of 
development  than  the  one  shown  in  fig.  4.  In  the  five  year  old  dog, 
as  has  been  mentioned  above,  I fonnd  only  a single  colony  of  cells 
and  no  apolar  cells.  The  resnlts  of  connting  the  ganglion  cells  and 
their  axons  indicaie,  however,  that  thei'e  really  are  apolar  cells  liere 
as  well ').  The  pnrely  morphological  observations  in  the  3.5  and 
5 year  old  dogs  do  not,  of  course,  qnite  exclnde  the  possibility  of 
there  being  colonies  of  cells  here  as  well  at  a vei'y  early  stage  of 
development,  bnt  with  regard  to  this  they  indicate  that  in  older 
animals  these  formations  are  relatively  very  rare.  It  is  to  be  noted 
that  such  eminent  investigators  as  Key  and  Retziüs^),  Schwalbe’) 
and  of  recent  years  Ranson  are  decidedly  against  the  opinion 
that  apolar  cells  are  to  be  found  in  the  spinal  ganglia  on  the  other 
hatid.  KölÜker®),  Müller'’)  and  others  hold  the  opinion  that  such 
cells  really  exist.  It  wonld  lead  me  too  fai'  from  my  real  subject 
were  I to  discuss  in  detail  the  literatnre  concerning  apolar  cells  in 
the  spinal  ganglia.  I must  content  myself  with  the  references  already 
given,  and  in  connection  with  this  point  I wish  to  state  that  there 
are  also  investigators  wlio  have  observed  processes  from  cells  in 
colonies  similar  to  those  described  above;  such  are  Arnot'^)  and 
Stienon *  *')  etc. 
’)  These  and  other  explanatory  details  will  be  given  more  fully  in  a forthcomiag 
and  more  complete  work. 
2)  Key  and  Retzius.  Studiën  in  d.  Anat.  d.  Nervensyst.  u.  Bindegewebe,  Bd.  2, 
1876. 
ScHWALBE,  Ai'ch.  f Mikr.  Anat.  Bd  4;  1868. 
*)  Ranson,  L.  c. 
Kölliker,  Handbuch  der  Gewebelehre,  5 Aufl.,  1867,  quoted  from  Muller  E. 
®)  Muller,  E.,  1 c. 
7)  Arndt,  Archiv  f.  Mikr.  Anat.,  Bd.  10,  1873. 
Stienon,  Annales  de  l’université  libre  de  Bruxelles,  1880,  quoted  from  Muller  E 
