1021 
andHoEKE‘).  Nageoïte’)  reprodiices  and  (^lescrihes  spinal  nerve-oells, 
in  wliicli  a collateral  leaves  the  axon  qiiite  close  to  tlie  nerve-cell. 
This  collateral  terminates  in  a club-like  swelling,  which  is  sitnated 
inside  the  capsule  of  the  saine  nerve-cell.  N.  is  of  the  0[)inion 
that  these  collaterals  are  dne  to  regenerative  activitj  in  the  cell, 
vvith  which  Cajal’)  alSo  agrees.  Bieeschowsky '')  interprets  these 
forniations  in  another  waj' ; he  inclndes  Ihein  atnong  the  fenestrate 
cells  and  thinks  that  these  processes  have  nothing  to  do  with  i’ege- 
neration.  Ranson®)  has  tried  to  discover  an  explanation  of  this 
phenomenon  by  means  of  experiinenis.  The  resiilts  given  by  these 
experiments  have,  without  exception,  indicated  that  these  [irocesses 
with  club-like  forniations  are  not  a product  of  regenerative  activity 
in  the  cell.  I have  however,  been  unable  to  tind  in  the  literature 
any  indication  of  the  fact  that  7-  and  l'-divisions  oecur  in  the  dorsal 
and  ventral  roots  of  the  spinal  nerves.  As  a working  hypothesis  for 
my  continued  investigations  I took  the  possibility  (which  is,  in 
itself,  not  at  all  probable)  that  the  above-inentioned,  or  similar, 
processes  with  club-like  forniations  might  develop  into  axons  and, 
in  addition,  the  possibility  that  7-  and  F-divisions  might  occur  in 
the  intra-  and  extra-niedullar  course  of  the  ventral  roots  as  well  as 
in  the  dorsal  roots,  which  vvould  explain  the  post-embryonal  increase 
in  the  axons  there  which  is  under  discussion. 
Silver  irnpregnated  dorsal  and  ventral  roots  of  lumbal  and  sacral 
nerves  in  connection  with  their  spinal  ganglia,  and  a small  piece  of 
half  the  spinal  cord  on  the  same  side  froin  animals  of  different  ages 
within  the  same  species,  were  set  up  in  unbroken  series  (10/^  thick). 
These  series  were  well  snited  for  studies  of  the  figures  of  the  growth 
that  might  possibly  occur,  and  for  investigations  made  with  a view 
to  answering  the  third  possibility  that  had  been  advanced,  namely 
whether  one  nerve  cell,  the  axons  of  which  form  the  spinal  nerves, 
sends  off  more  than  one  axon  in  the  same  direction.  In  investigating 
the  preparation  a cross-table  was  used  and  the  microscope  was 
h Boeke,  J.  Studiën  zur  Nervenregeneration  II  Verhandel,  d.  K.  Akad.  v.  Wet. 
te  Amsterdam.  Deel  XIX.  N^* *.  5.  1917. 
*)  Nageotte,  J.  Recherches  experimentales  sur  la  morphologie  des  cellules  et 
des  fibres  des  ganglions  rachidiens  Rev.  Neurol.  Paris.  Vol.  15,  p.  357. 
Gajal  S.  Ramon  y.  Die  Struktur  der  sensiblen  Gangliën  des  Menschen  und 
der  Tiere.  Anat.  Heft.  Zweite  Abt.  Bd.  16.  1907. 
h Bielschowsky,  M.  Ueber  den  Bau  der  Spinalganglien  unter  normalen  und 
pathologischen  Verhaltnissen.  J.  Psych  u.  Neur.  B.  11,  1908.  Leipzig. 
Ranson,  S.  Walter.  The  Structure  of  the  Spinal  ganglia  and  of  the  spinal 
nerves.  J.  Gomp.  Neur.  Vol.  22,  1912. 
