nal ear--comprising the fleshy portion of the ear,
or auricle, and the opening, or canal, about an inch long--is
separated from that portion of the ear within (or middle ear) by the
drum membrane. The middle ear, while protected from the outer air by
the drum, is really a part of the upper air passages, and participates
in disorders affecting them. It is the important part of the ear as it
is the seat of most ear troubles, and disease of the middle ear not
only endangers the hearing, but threatens life through proximity to
the brain.

In the middle ear we have an air space connected with the throat by
the Eustachian tube, a tube about an inch long running downward and
forward to join the upper air passage at the junction of the back of
the nose and upper part of the throat. If one should run the finger
along the roof of the mouth and then hook it up behind and above the
soft palate one could feel the openings of these tubes (one for each
ear) on either side of the top of the throat or back of the nose,
according to the view we take of it.

Then the middle ear is also connected with a cavity in the bone back
of the ear (mastoid cavity or cells), and the outer and lower wall is
formed by the drum membrane. Vibrations started by sound waves which
strike the ear are connected by means of a chain of three little bones
from the drum through the middle ear to the nervous apparatus in the
internal ear. The head of one of these little bones may be seen by an
expert, looking into the ear, pressing against the inside of the drum
membrane. Stiffening or immovability of the joints between these
little bones, from catarrh of the middle ear, is most important in
producing permanent deafness. The middle ear space is lined with
mucous membrane continuous with that of the throat through the
Eustachian tube. This serves to drain mucus from the middle ear, and
also to equalize the air pressure on the eardrum so that the pressure
within the middle ear shall be the same as that without.

When there is catarrh or inflammation of the throat or nose it is apt
to extend up the Eustachian tubes and involve the middle ear. In this
way the tubes become choked and obstructed with the oversecretion or
by swelling. The air in the middle ear then becomes absorbed in part,
and a species of vacuum is produced with increased pressure from
without on the eardrum. The drum membrane will be pressed in, and
through the little bones pressure will be made ag