482.]  A  caries  in  some  part  of  the  t^h,  whether  aris^
iDg  upon  their  internal  surface  or  upon  their  external,
proceeding  so  far  as  to  reach  the  nerves  in  the  cavity  of
the  teeth  y  is  pretty  manifestly  the  cause  of  toothach,  and
jof  the  first  attacks  of  it ;  but  when  the  cavity  of  the  teeth
has  been  opened,  so  that  the  external  air  or  other  matters
can  reach  that  cavity,  these  are  often  the  exciting  causey
ei  toothach,  aiui  serve  ta  prove  in  general,  that  acrid
matters  applied  to  the  nerves  occasion  the  disease.
483.]  What  isthe  nature  of  the  matter  produced  in  the
caries  of  the  teeth,  I  do  not  understand,  nor  have  I  found
any  proper  corrector  of  it ;  but  1  presume  it  to  be  of  the
putnd  kind,  as  it  often  taints  the  breath  with  a  fetid  odour.
,  484.]  In  the  cure  of  tlus  disease,  a  long  experience  has
shown,  that  the  extraction  of  the  carious  tooth  proves  the
0io$t  eflectual,  and  very  often  the  only  effectual ,  remedy
of  the  disease.  .  But  as  m  some  cases  this  extraction  is  not
proper,  and  as  in  many  cases  it  is  obstinately  avoided,
other  means  of  curing,  the  disease,  or  at  least  of  relieving
the  pain  have  been  sought  for  and  much  practised.
