The  infantile  variety  has  been  known  to  follow  exposure  to  cold  or
dampness,  overfatigue  of  the  muscles,  some  forms  of  blood-poisoning
(such  as  eruptive  fevers,  diphtheria,  lead-poisoning,  etc.),  dentition,  and
traumatism.  Some  cases  develop  from  imi)erfectly  understood  causes.
It  generally  occurs  before  the  second  year, — seldom  later  than  the  seventh
3'ear.     It  is  most  common  among  boys.
The  adult  variety  seems  to  be  excited  chiefly  by  exposure  to  cold  or
dampness  and  overexertion.  Lead-poisoning  is  said  to  sometimes  excite
it.     Debilitv,  convalescence   from   fevers,  malaria,  pneumonia,  etc.,  are


INFLAMMATION   OF   CELLS   OF   ANTERIOR   HORNS.  369

mentioned  by  authors  as  among  its  fixctors  of  causation.  It  ma^'  develop
between  the  ages  of  twenty  and  fifty  years.  One  of  my  patients  (Figs.
99  and  100)  was  so  affected  (after  severe  exertion  and  excessive  in-
dulgence in  alcohol)  from  sleeping  on  the  ground  during  a  summer
shower.  The  paralysis  in  this  case  attacked  the  muscles  which  were
fliietly  employed  by  him  in  his  occupation.
Symptoms. — The  three  forms  of  this  disease  will  be  described
separately,  as  the}'  should  be  distinguished  at  the  bedside.
Acute  Form.  {Infantile  Spinal  Paralysis — Acute  Spinal  Paralysis  of
Adults.) — The  onset  of  this  form  is  usually  marked  by  a  sudden  elevation  of


Fig.  9P.— Poliomyelitis  Anterior  Ac  n  \,  oc  lki;i:.(.  in  the  Adult  from  Sleeping  on
Wet  Ground.  (From  a  photograph  in  the  possession  of  the  Author. )  Note  the  extensive
atrophy  of  deltoid  region,  forearm,  and  hand.
temperature.  The  febrile  symptoms  may  be  either  continued  or  remittent
in  type.  The  fever  may  last  from  twenty-four  hours  to  several  days.  It
is  not  uncommon  to  observe  pains  in  the  limbs,  muscular  twitchings,
tremors,  convulsions,  delirium,  and  occasionally  a  sense  of  numbness  in
connection  with  the  stage  of  fever.
