the  sequestrum,  and  the  cause  of  the  necrosis.  GeneraUy  speaking  the
proper  time  for  sfquestrolomy.  i.e..  removal  of  the  sequestrum,  is  two  or  three
months  after  the  original  operation  for  drainage.  The  bone  is  exjxised  by  a
suitable  incision,  the  periosteum  retracted,  sufficient  involucrum  removed
by  gouge  or  chisel,  the  dead  bone  extracted  with  forceps  (Fig.  212),  and  the


l-tc.  ju.— (1)  rrriostcal  tcparator,  (i)  lion-jawed  forcepi.  (j)  curdle,  Ul  >«4U»lniin
lorcept,  (si  Macewen'f  osleolome  (6)  chisel,  (;)  gousc.  (8)  chain  saw,  (g)  bone  cutlinc
forcepf.
cavity  irrigated  with  an  antiseptic  solution  and  packed  with  iodofonn  gauze.
If  the  scqui'strum  has  not  separated,  the  dead  bone  must  be  chiseled  awav.
Dead  b<ine  is  softer  than  normal,  often  whitish  in  apfiearance.  and  does  not
bleed  when  cut.     If  the  cavity  is  small  it  rapidly  fills  with  granulations,  which


CARIES.
339


are  ultimately  replaced  by  bone.  If  il  is  larKe.  liealing  is  very  slow,  hence  the
following  methods  10  assist  repair.  The  cavity  has  been  filled  with  aseptic
sponge,  decalcified  bone  chij)s,  gutta-percha,  plaster-of-Paris,  lead,  blood
clot,  mixture  of  paraflin  and  iodoform,  etc.,  but  owing  to  the  presence  of
infection,  such  materials  act  simply  as  foreign  bodies  and  are  ultimately
discharged.  Recently,  however,  encouraging  results  have  been  obtained
with  Moorhoj's  bonr  wax.  which  consists  of  iodoform  20  parts,  spermaceti  40
parts,  and  oil  of  sesame  40  parts.  The  cavity  is  rendered  dry  and  sterile,  and
the  mixture,  heated  to  50°  C,  jxiured  into  the  cavity  and  allowed  to  solidify.
