(a)  Motility. — The  manner  in  which  the  tongue  is  protruded  upon
request  is  often  suggestive:  Under  ordinary  circumstances  the  movement
is  commonplace  and  familiar.  In  very  ill  patients  the  tongue  is  protruded
slowly  and  incompletely.  In  the  advanced  stages  of  enteric  fever  the
patient  protrudes  his  tongue  hesitatingly  and  does  not  immediately  with-
draw it  unless  requested.  In  chorea  the  tongue  is  thrust  out  with  a  pecu-
liar jerk  and  immediately  withdrawn.  In  well-marked  cases  it  is  impos-
sible for  the  patient  to  keep  it  out  for  any  length  of  time.  Spasm  of  the
muscles  of  mastication  renders  it  impossible  to  protrude  the  tongue.  The
spasm  may  be  tonic  or  clonic;  in  rare  instances  it  occurs  as  an  independent
affection.  It  is  usually  part  of  general  convulsive  disease.  In  the  tonic
form  the  jaws  are  held  forcibly  together — lockjaw.  The  masseter  and
temporal  muscles  are  tense  and  hard  and  the  spasm  is  frequently  attended
with  pain.  It  is  an  early  and  prominent  symptom  in  tetanus  and  occurs
also  in  tetany.  There  is  tonic  spasm  of  the  jaw  muscles  in  trismus  neona-
torum and  strychnia  poisoning  and  sometimes  in  hysteria  and  epilepsy.
