Ulceration  of  the  lining  membrane  is  an  affection  less  frequently
met  with.  It  is  rarely,  if  ever,  idiopathic,  but  seems  rather  to  be  de-
pendent upon  some  other  local  malady  or  some  specific  constitutional
vice.  Scorbutic  and  scrofulous  diatheses,  and  those  affected  with  a
venereal  taint,  are  more  liable  to  ulceration  of  this  membrane  than
persons  of  sound  constitution.  Consequently,  it  is  seldom  cured  by
local  remedies  alone.  It  is  almost  always  complicated  with  fungus  of
the  membrane  and  caries  of  the  walls  of  the  sinus,  and  may,  if
neglected,  take  on  a  cancerous  form  and  become  incurable.
The  next  form  of  disease  is  caries  of  the  antral  parietes.  This,  though
always  complicated  with  other  forms  of  diseased  action,  seems,  never-
theless, to  be  worthy  of  separate  consideration.  Like  ulceration  of  the
lining  membrane,  it  is  the  result  of  some  other  affection.  It  may  result
from  accumulation  of  the  secretions  of  the  sinus,  from  ulceration,  or
from  tumors.
The  occurrence  of  fungus  and  of  various  kinds  of  tumor  is  less  fre-
quent than  any  of  the  preceding  affections ;  yet  this  cavity  is  not  exempt
from  them,  and  they  constitute  the  most  dangerous  form  of  disease  to
which  the  superior  maxilla  is  subject.  Although  it  is  ])robable  that,*
in  their  incipient  stage,  they  might  in  nearly  every  instance  be  radi-
cally removed,  it  is  seldom  they  are  cured  after  they  have  attained  a
very  large  size,  and  have  implicated,  to  considerable  extent,  the  sur-
rounding tissues.  They  have,  however,  been  successfully  extirpated
even  after  they  had  required  great  volume,  and  implicated  to  such  an
extent  the  surrounding  parts,  as  to  render  necessary  the  removal  of
the  whole  of  the  superior  maxillary  bone.  They  usually  grow  with
great  rapidity,  and,  if  not  completely  removed,  are  soon  reproduced.
