iii.  Arteriovenous  Aneurism.
That  form  which  results  from  the  rupture  of  an  aneurism  of  the  ascend-
ing portii)n  of  the  arch  of  the  aorta  into  the  descending  vena  cava  is  of
special  clinical  interest.  It  is,  however,  extremely  rare.  The  symptoms
usually  occur  abruptly  and  consist  of  marked  dilatation  of  the  veins  of
the  upper  part  of  the  body,  with  cyanosis  and  (edema.  A  continuous
murmur  with  systolic  intensification  and  a  systolic  thrill  may  be  recognized.
iv.  Periarteritis  Nodosa ;  Congenital  Aneurism.
The  medium-sized  arteries,  especially  those  of  the  muscles,  and  the
heart,  spleen,  liver,  kidneys,  intestines,  and  the  skin  are  the  seat  of  whitish
nodular  masses,  varying  in  size  from  a  small  shot  to  a  large  pea,  and  great
numbers  of  small  aneurismal  dilatations.  The  disease  has  occurred  in
both  sexes.  It  manifests  itself  most  commonly  in  early  and  middle  adult
life.  It  has  been  ascribed  to  syphilis  and  to  septic  conditions.  It  is  ex-
tremely rare.  The  prominent  symptoms  are  weakness,  ansemia,  and
rapidity  of  the  pulse.  There  is  at  first  fever,  which  presently  falls  without
a  corresponding  decline  in  the  pulse-frequency.  When  the  muscular
branches  are  involved,  pain,  weakness,  and  atrophy  occur.  When  the
arteries  of  the  gastro-intestinal  canal  are  the  seat  of  the  lesions,  epigastric
pain,  thirst,  anorexia,  nausea  and  vomiting,  and  diarrhoea  or  constipation
are  prominent  symptoms.  Hemorrhage  from  the  bowels  has  l)ecn  observed.
Scanty  urine,  of  low  specific  gravity,  albumin,  and  casts  occur.  Urea  is  di-
minished. Anaemia  is  marked.  I^eucocytosis  is  common.  The  course  of  the
4lisease  is  progressive,  and  death  occurs  at  the  end  of  the  second  or  third
month.  Recovery  is  exceptional.  The  diagnosis  is  usually  post  mortem.
