936 
whether  tliere  is  a motor  doublé  innervation  or  a doublé  innerva- 
tion  by  means  of  a motor  and  a sympathetic  terminal  plate.  This 
point  will  be  discussed  at  greater  length  in  a future  and  more 
detailed  account. 
Snnimary.  i 
All  tbe  spinal  nerves,  whose  ventral  ramifications  form  the  plexus  j 
brachialis,  have  in  some  cats  been  cut  ofF  between  the  spinal  ganglion  i 
and  the  place  where  the  ramus  communioans  albus  goes  otF.  When  j 
from  tive  to  ten  days  had  elapsed  after  the  operation,  the  animals  | 
were  killed.  In  sections  of  Ag.-impregnated  mm.  interossei  from  the 
anterior  extremity  on  the  side  operated  on  I found  that  all  the 
nei've  tibres  that  had  medullary  slieaths  were  degeneiated,  but  that 
thei'e  were  fairly  numerous  intact  nerve  tibres  without  medullary 
sheaths.  On  account  of  the  operations  the  animals  had  undergone  j 
and  the  existing  period  of  degeneration  in  the  spinal  nerves  that  I 
had  been  cut  otf  I have  reason  to  believe  that  these  intact  non  i 
medullated  nerves  are  of  a sympathetic  and  post-ganglionar  nature. 
We  are  thus  faced  by  the  exceedinglj"  inreresting  tact  that  the  cross- 
striated  rnuscle  fibres,  eveii  in  the  muscles  of  the  extremity,  are 
innervated  by  n.  sympathicns  — corresponding  to  what  Boeke  showed 
morphologically  to  be  the  case  for  the  inner  orbital  muscles  (m. 
obliquus  ocnli  superior).  These  sympathetic  nerves  in  the  extremity 
musculature  terminate  in  comparalivel}'  simple  loop  — formations 
partly  (among  other  plaoes)  on  ordinary  eross-striated  rnuscle  fibres 
and  partly  on  mnsele  tibi'es  in  the  rnuscle  spindles.  I have  reason 
to  believe  that  the  great  majority  of  these  sympathetic  terminal 
plates  — both  on  ordinary  rnuscle  tibres  as  well  as  on  those  in  the 
rnuscle  spinalles  — are  siluated  hy po-lemmally  — just  as  Boeke  ' 
described  them  in,  among  other  places,  m.  obliquus  oculi  sup.  ofthe 
cat.  1 have  also,  however,  preparations  which  indicate  that  there  i 
are  also  epilemmally  situated  sympathetic  terminal  plates  in  the 
extremity-musculatiire.  A number  of  the  sympathetic  terminal  plates 
on  ordinary  cross-striated  rnuscle  tibres  are  situated  within  the  region 
of  extension  of  the  motor  plates,  but  the  majority  lie  outside  it. 
Among  the  sympathetic  terminal  plates  that  are  situated  outside  the 
region  of  the  motor  plates  I have  examples  of  some  that  have  a 
rather  large  extension  on  the  rnuscle  fibres  and  that  on  account  of 
this,  approach  the  motor  terminal  plates. 
