1024 
As  tliis  atteiiipt  to  explaiii  (lie  iiicrease  aetiiallj  existing  in  tlie 
numbei-  of  nerve  fibres  in  the  dorsal  and  ventral  roots  of  the  spinal 
nerves  as  a resnlt  of  a division  of  the  axons  was  nnsnecessful,  I 
liad  to  proceed  to  investigate  other  possibililies.  The  following  possi- 
bility  lias  now  to  be  closelj  considered. 
Is  it  possible  that  a nerve-cell  may  send  o f more  than  one  axon  in 
the  snme  direction? 
In  ordei’  to  be  able  to  answer  tliis  qnestion,  I have  carried  out 
investigations  in  two  directions.  I tirst  investigated  carefully  the 
preparatioiis  left  over  froin  the  preceding  series  in  whieh,  ofcourse, 
whole  spinal  ganglia  and  parts  of  the  ventral  horn  were  set  up  in 
nnbrokeii  series,  and  seeoiidly  I connied  all  the  cells  in  a ventral 
horn  of  a 10  days’  old  and  of  a 360  days’  old  ddus  musculus  var.  albus 
— bet  ween  the  exits  for  two  spinal  nerves  from  coi’responding 
segments  — and  also  all  the  cells  in  a spinal  ganglion  similarly 
situated  in  the  two  aninials.  The  values  obtained  for  the  numbers 
of  cells  have  been  conipared  with  the  nurnber  of  axons  in  the 
corresponding  ventral  and  dorsal  roots.  One  cannot,  of  course,  expect 
to  obtain  in  these  two  ways  an  answer  to  the  aforesaid  qnestion 
that  would  be  a priori  absolntely  certain,  but  it  seems  to  nie  that 
they  take  us  as  far  as  we  can  geneially  go  with  inorphological 
methods  of  investigation.  A careful  investigation  (of  the  above-men- 
tioned  nnbroken  series)  of  the  nerve-cells  in  the  ventral  horns  and 
in  the  spinal  ganglion  did  not  produce  a single  figure  to  support 
the  supposition  of  more  than  one  axon  being  sent  ofF  in  the  same 
direction  from  the  nerve-cell.  It  is  certainly  true  that  in  the  spinal 
ganglion  there  were  nerve-cells  whieh  have  processes  beside  the 
axon,  but  in  no  single  case  could  these  be  followed  up  to  a J’-division. 
Spinal  ganglion-cells  of  this  sort  are  described  by  Ranson  and 
others.  I am  of  the  opinion  that  this  part  of  the  investigation  produced 
a negative  resnlt. 
With  regard  to  the  calculations  as  to  the  nurnber  of  cells,  they 
showed  that  the  numbei'  in  the  older  specimen  was  certainly  greater 
than  in  the  younger  one,  but  the  difference  is  not  so  large  compared 
with  the  difference  in  the  nurnber  of  axons  in  the  same  specimens. 
The  nurnber  of  axons  seems  thus  to  increase  in  a relatively  higher 
degree  than  the  uumbei'  of  ganglion-cells  during  the  post-embryonal 
(leriod.  This  fact  seems,  of  course,  to  allow  the  possibility  that  the 
same  nerve-cell  might  send  more  than  one  axon  into,  for  instance, 
the  dorsal  and  xentral  roots.  There  is,  however,  another  and  more 
b L.  c. 
