932 
taken  shonld  be  sufficiënt  to  show  degeneration  (periplierically  of 
the  place  where  the  cut  was  made)  in  Ag  — impregnated  prepa- 
rations  of  the  nerve  tibies  that  had  been  cut  otï.  Telt, o')  gives 
further  details  about  the  time  of  the  appearance  of  degeneration 
that  can  be  shown  morphologically  in  the  nerves  peripherically  of 
the  place  of  the  section. 
The  plexus  brachialis  of  the  cat  is  generally  formed  by  the 
ventral  bianches  of  the  tirst  thoracic  ner\e  (1  have  sometimes,  how- 
ever,  observed  a tine  branch  from  the  second  thoracic  nerve)  and 
the  last  three  cervical  ner\'es.  As  is  shown  above,  one  segmental 
nerve  cranially  and  oue  caudally  of  those  that  generally  form  the 
plexus  had  thus  been  caused  to  degenerate.  This  was  done  to  ensure 
complete  certainty  that,  even  if  some  branch  might  possibly  come 
from  these  contiguous  nerves  to  the  anterior  exti'emities,  all  the 
spinal  nerves  there  would  have  undergone  degeneration.  After  the 
animal  had  been  killed,  the  results  of  the  operation  were  carefully 
veiitled,  and  they  were  found  to  l)e  good.  The  animal  in  question 
had  110  branch  froni  the  second  thoracal  nerve  to  the  plexus  brachialis. 
After  the  blood  had  been  removed  by  injecting  physiological  solution 
of  common  salt  froin  the  heart,  the  anterior  extrernity  on  the  side 
where  the  animal  had  undergone  the  operation  was  tixed  by  inject- 
ing a twenty  per  cent  solution  of  formaldehyd  from  the  a.  axillaris. 
The  extremity  was  kept  for  some  time  in  formalin.  The  mm.  interossei 
were  impregiiated  according  to  my  moditications ’)  of  Biei,schowsky’s 
method  of  silver  impregnation. 
It  was  clear  from  sections  of  the  impregnated  muscles  that  all 
the  myelinized  nerves,  both  the  motor  ones  and  the  sensory  ones, 
had  undergone  degeneration.  On  the  other  hand  I found  quite  a 
number  of  intact  non-medullated  nerves.  These  intact  nerves  were 
found  in  the  preparations  partly  together  with  bundles  of  degenerated 
spinal  nerves  and  partly  along  vessels.  I was  able  to  follow  a large 
number  of  the  intact  non-medullated  nerves  out  to  their  terminal 
organs.  These  terminal  organs  were  situated  partly  on  ordinary 
cross-striated  muscle  fibres  and  partly  on  muscle  fibres  in  muscle- 
spindles.  I shall  give  a more  detailed  account  of  the  sympathetic 
terminal  organs  in  muscle  spindles  in  a later  and  more  complete 
h Tello,  F.  Dégénération  et  régénération  des  plaques  motrices  après  la  section 
des  nervs.  Travaux  du  laborat.  de  rech.  biolog.  publ.  par  S.  R.  Gajal,  Tomé  V, 
1907. 
*)  Ebik  Agdur:  Ueber  Stückfarbung  mit  Bielschowskys  Silberimpragnations- 
methode.  — Einige  Modifikationen.  Zeitschr.  f.  wiss.  Mikrosk.  u.  f.  mikrosk. 
Techn.,  Bd.  34,  1917. 
