Necroscopy. — Autopsic  examination  uniformly  reveals  to  us  all  the
appearances  of  high  inflammation  of  the  intestinal  mucous  surface,
chiefly  of  the  colon  and  rectum;  patches  of  this  tissue  are  deeply  in-
jected, infiltrated  with  blood  and  softened ;  and  if  the  case  have  been
of  any  duration,  ulcers  are  formed  of  various  size  and  shape,  exten-
sively diffused.  The  canal  is  sometimes  found  constricted.  Gangrene
and  sphacelus,  separating  considerable  lengths  of  the  tube,  are  known
to  have  taken  place.
Causes. — Dysentery  occurs  sporadically,  and  as  an  epidemic;  in  the
latter  form,  its  ravages  have  at  times  been  dreadful  indeed.  Of  late
years  it  has  been  the  most  frequent  and  extensive  of  all  the  epidemics
of  our  own  country,  extending  summer  after  summer  from  Maine  to
Texas,  and  from  the  great  lakes  to  the  Atlantic  coast.  Cullen,  as  I
have  remarked,  asserts  it  to  be  uniformly  and  essentially  contagious,
and  the  doctrine  has  received  very  able  and  extensive  support  from
others.  And  even  among  those  who  refuse  to  consider  dysentery  as  in
itself,  uniformly  or  essentially  contagious,  there  are  few  who  doubt  that
it  may  assume  this  character  or  quality,  under  particular  circumstances
— as  in  camps,  jails,  hospitals  and  other  crowded  and  ill-ventilated
places,  and  when  the  attendant  fever  takes  the  typhoid  type.
