Loss  of  power  usually  commences  in  the  legs,  and  steadily  increases,  with
loss  of  all  reflex  action,  but  with  no  affection  of  sensibility.  Muscular  wast-
ing occurs  irregularly,  some  groups  of  muscles  being  chiefly  involved.  The
upper  limbs  are  affected  after  the  lower,  but  in  a  similar  manner.  The  mus-
cles usually  present  the  degenerative  reaction,  loss  of  faradaic  irritability
with  increased  and  altered  voltaic  irritability,  but  in  some  cases,  in  conse-
quence of  the  unequal  affection  of  the  nerve  fibres,  there  is  the  mixed  form


274  SPINAL   CORD.
