In  consequence  of  this  muscular  condition,  certain  complex  movements
are  performed  in  a  peculiar  and  characteristic  manner.  One  of  these  is
walking.  The  patient  rises  up  slowly  from  the  chair  with  head  and  shoulders
bent  forward.  His  steps  are  short,  and  the  first  may  be  taken  slowly  and
with  difficulty,  but  they  become  quicker  and  quicker,  until  the  patient  seems
to  be  about  to  run  ("  festination  "),  and  often,  from  the  inclination  of  the
body,  to  be  on  the  point  of  falling  forward  ("propulsion").  It  has  been
thought  that  this  tendency  to  run  is  due  simply  to  the  forward  inclination  of
the  body ;  the  patient,  as  Trousseau  expressed  it,  has  to  run  after  his  centre
of  gravity,  but  that  this  is  not  the  whole  explanation  is  shown  by  the  fact  that
some  patients,  suddenly  jerked  backward,  may  exhibit  a  tendency  to  walk
backward,  which  they  are  unable  to  avoid  ("  retropulsion  "),  and  this  although
they  stoop  forward^  It  is  indeed  not  uncommon  for  patients  to  be  able  to
walk  backward  better  than  forward.  In  one  case  an  irresistible  tendency  to
run  backward  existed  only  on  first  rising  in  the  morning.  Usually  the
patients'  equilibrium  is  easily  disturbed,  and  even  when  they  walk  fairly  well,
they  have  considerable  difficulty  in  turning  suddenly.  One  patient,  in  turn-
ing, often  took  a  few  unintended  steps  to  one  side.
The  slowness  of  muscular  action  is  usually  conspicuous  in  all  movements,
but  it  rarely  affects  the  muscles  of  the  eyes.  If  the  patient  is  to  look  in  a
given  direction,  the  eyes  are  instantly  turned,  while  the  head  slowly  follows
them.*  Speech  has  usually  a  well-marked  characteristic :  the  voice  is
monotonous,  being  no  more  varied  by  emotional  expression  than  is  the  face.
