The  blood  in  malarial  disease  is  deficient  in  albumen,  fibrin,  and
red  corpuscles,  which  explains  the  co-existing  anemic  condition,
palpitation  of  the  heart,  and  cedematous  condition  of  the  skin.  In
this  disease  the  liver  and  spleen  are  always  enlarged,  the  enlarge-
ment of  the  spleen  being  brought  about  by  the  damming  up  of  the
blood  in  the  portal  vein  and  its  tributaries.  Again,  the  blood  is
defectively  developed,  owing  to  the  deranged  state  of  the  stomao£ir
bowels,  and  blood-making  organs.
THE    BLOOD.  85

The  coagulation  of  blood  depends  on  the  presence  of  fibrin.
Fibrin,  though  present  in  such  very  small  quantity  (only  3  parts
in  1000  of  blood),  exhibits  its  great  importance.  When  blood  is
gradually  withdrawn  from  the  blood-vessel,  it  is  this  fibrin  which
causes  its  coagulation.  Fibrin,  however,  does  not  exist  in  blood  as
such.  There  are  two  substances — the  globulin  of  the  corpuscles  and
fibrinogen  in  the  plasma — which  unite  to  form  the  fibrin  of  the  coag-
ulum.  A  portion  of  thefibrinous  elements  of  blood  disappears  in  pass-
ing through  the  capillary  circulation,  showing  that  venous  blood
contains  less  of  these  elements  than  arterial.  In  the  liver  and  kid-
neys it  entirely  disappears,  so  that  none  is  found  in  the  renal  and
hepatic  veins.  This  demonstrates  clearly  that  it  is  produced  else-
where, and  is  always  of  recent  formation,  its  quantity  remaining  un-
changed. When  a  congenital  deficiency  of  fibrinous  elements  exists
in  the  blood,  no  clot  can  form  in  a  ligated  vessel ;  so  that  if  a  liga-
ture be  applied  and  afterwards  removed,  bleeding  begins  again.
Another  ligature  is  likewise  followed  by  a  secondary  haemorrhage.
