During  the  time  the  tampon  remains  in  the  nose  the  patient  should
assume  a  sitting  posture  to  avoid  the  possil)le  escape  of  some  of

1  Escat:  Dental  Register,   1907,  p.   306.
•  Dc  Terra:  Correspondenzblatt  fiir  Zahnarztc,   1908,  p.   244.
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542  LOCAL  ANESTHESIA

the  liquid  into  the  posterior  nares/^  Escat  has  studied  with  the
utmost  care  the  effects  of  nasal  anesthesia  on  the  teeth,  and  sum-
marizes the  results  of  his  observations  as  follows :

1.  In  thirty-six  cases  a  complete  anesthesia  was  obtained  of
the  central  incisor  and  of  the  canine  on  the  side  corresponding
to  that  of  the  nasal  fossa  subjected  to  the  action  of  the  anesthetic;
also  an  incomplete  anesthesia  of  the  first  bicuspid  adjoining  the
anesthetized  cuspid,  and  of  the  lateral  incisor  on  the  opposite  side.
2.  In  eight  cases  the  anesthetized  area  included,  in  addition  to
the  incisors  and  canine  on  the  corresponding  side  of  the  anes-
thetized nasal  fossa,  the  incisors  and  canine  on  the  opposite  side.
3.  In  one  case  the  anesthesia  of  the  incisors  and  canine  on  the
opposite  side  of  the  anesthetized  nasal  fossa  was  complete,  while
that  of  the  incisors  and  canine  on  the  corresponding  side  was  in-
complete.
In  order  to  explain  this  form  of  anesthesia,  Escat  offers  the
following  plausible  explanation:

1.  The  infiltration  of  the  floor  of  the  nose,  the  penetration
through  the  mucous  lining  and  the  thin  lamina  of  bone,  and  the
absorption  by  the  lymphatics  carry  the  anesthetic  solution  to  the
nerves  supplying  the  teeth.
