The  first  is  incomparably  the  most  important,  since  by  it  the  treatment  has
to  be  determined.  Unfortunately,  it  is  often,  of  all  the  diagnostic  prob-
lems presented  to  the  physician,  at  once  the  most  difficult  and  the  most
urgent.
The  first  question  in  diagnosis  is,  whether  an  attack  of  apoplexy  is  of
cerebral  origin.  The  chief  points  in  the  differential  diagnosis  have  been
considered  in  the  account  of  this  condition.  If  cerebral  symptoms,  such  as
unilateral  numbness  or  weakness,  have  preceded  the  loss  of  consciousness,  or
are  to  be  traced  in  it,  as  by  one-sided  relaxation  of  limb  or  deviation  of  the
head,  the  cerebral  nature  of  the  attack  is  clear.  If  these  are  absent  the
question  must  be  determined  by  the  considerations  mentioned  at  p.  534.
An  actually  sudden  onset  limits  the  diagnosis  to  the  distinction  from  syncope,
and  this  should  be  easy.  If  the  onset  was  gradual,  or,  as  is  often  the  case,
its  character  cannot  be  ascertained,  the  distinction  has  to  be  made  from
poisoning  (especially  by  chloral,  opium  and  alcohol),  and  from  uraemia,  by
the  indications  already  described  in  the  section  on  apoplexy.
