These  constitute  the  pe-
duncular tract.  Some  of
these  fibers  were  shown
in  the  diagram  illustrating


the  paths  in  the  spinal
cord  (Fig.  14) ;  the  whole
system  is  shown  m  Fig.  16.
Second,  there  are  fibers,  as


FIG.  1  8.  A  transverse  section  across  the

two  hemispheres  in  a  plane  passing  verti-

cally  through  the  cheek  bones  parallel

to  a  line  connecting  4hc  two  ears

This  section  shows  the  fibers  which  establish

communication  between  the  two  hemispheres,      shown    in    Fig.    \J,    which

When  the  fiber,  in  this  figure  are  supple-  connect  the  different  points
mented  by  those  represented  in  the  two
preceding  figures,  it  will  be  seen  that  every
point  on  the  cortex  of  the  cerebrum  is  in
communication  with  all  other  parts  of  the
nervous  system.  (After  Edinger)


of  the  cortex  of  one  hemi-
sphere with  other  points
in  the  same  hemisphere.
These  fibers  are  techni-
cally known  as  association  fibers.  The  third  bundle  of  fibers
extends  from  one  hemisphere  of  the  cerebrum  to  the  other
hemisphere.  The  fibers  of  this  group  are  known  as  the
commissural  fibers,  and  go  to  make  up  the  corpus  callosum,
or  bridge  of  fibers,  conspicuous  in  any  median  section  of
the  cerebrum  and  shown  in  Fig.  18.  This  bridge  was  also
shown  in  Fig.  16.
