84.  Gouled  vs.  U.  S.,  255  U.  S.  298;  65  L.  Ed.  311;  41  Sup.  Ct.  261.
85.  Amos  V8.  U.  S.,  255  U.  S.  313;  65  L.  Ed.  316;  41  Sup.  a.  266.
88.  Weeks  vs.  U.  S.,  supra,  at  page  398.
132  FEDERAL   JURISDICTION   AND  PROCEDURE.
is  a  principal.  The  common  law  rule  governing  the  par-
ticipants in  the  commission  of  misdemeanors  has,  there-
fore, been  extended  by  Congress  to  all  those  who  are  in
anywise  concerned  in  the  commission  of  a  felony.
125.  In  Oriminal  Trials  in  the  Federal  Courts  Juries  Are
Not  Judges  of  the  Law.
After  the  evidence  is  all  in,  it  becomes  necessary  to
determine  what  the  applicable  law  is.  In  Maryland  and
in  some  other  States,  the  jury  in  criminal  cases  are  the
judges  both  of  the  law  and  of  the  facts.  In  the  Federal
Courts  this  is  not  so.  In  both  civil  and  criminal  cases
the  judge  instructs  the  jury  as  to  what  the  law  is.  It  is
his  duty  so  to  do.  It  is  their  duty  to  accept  the  law  as
he  declares  it  to  be.  This  duty  is  however,  a  moral  one
only.  It  may  be  that  the  facts  in  the  case  are  practically
undisputed.  They  may  make  out  a  clear  case  of  guilt.
The  judge,  however,  cannot  instruct  the  jury  to  find  a
verdict  of  guilty.  He  cannot  set  aside  a  verdict  of  not
guilty  if  they  return  it.  A  person  who  has  been  once  put
in  jeopardy  cannot  for  the  same  offense  be  again  tried,
unless  the  first  verdict  is  set  aside  at  his  instance.
