The illustration on the opposite page shows the interior structure of the ear. The concha and =Meatus=, or canal, comprise the external ear, which is separated from the middle ear by the =Drum Membrane=. Wax is secreted by glands located in the lining of the meatus, and should be detached by the motion of the jaws during talking and eating. If it adheres to the drum membrane it causes partial deafness. The internal ear, or labyrinth, a cavity in the bone, back of the middle ear, consists of three parts: the =Cochlea=, the =Semicircular Canals=, and a middle portion, the =Vestibule=. The middle ear is connected with the throat by the =Eustachian Tube=. Sound vibrations, which strike the drum membrane, are conveyed by means of a chain of three small bones through the middle ear to the nervous apparatus of the internal ear. The Eustachian tube and middle ear are lined throughout with mucous membrane, and any severe inflammation of the throat may extend to and involve the tube and the middle ear, causing deafness.] =MODERATE OR SLIGHT EARACHE.=--A slight or moderate earache, which may, however, be very persistent, not sufficient to incapacitate the patient or prevent sleep, is often caused by some obstruction in the Eustachian tube, either by swelling or mucous discharge. This condition gives rise to the train of effects noted in the section on deafness. The air in the middle ear is absorbed to some extent, and therefore the pressure within the ear is less than that outside the drum, so that the latter is pressed inward with the result that pain, and perhaps noises and deafness ensue, and, if the condition is not relieved, inflammation of the middle ear as described above. =Treatment.=--Treatment is directed toward cleaning the back of the nose and reducing swelling at the openings of the Eustachian tubes in this locality, and inflating the tubes with air. A spray of Seiler's solution[3] is thrown from an atomizer through the nostrils, with the head tipped backward, until it is felt in the back of the throat, and after the water has drained away the process is repeated a number of times. This treatment is pursued twice daily, and one hour after the fluid in the nose is well cleared away the Eustachian tubes may be inflated by the patient. To accomplish this the lips are closed tightly, and the nostrils also, by holding the nose; then an effort is made to blow the cheeks out till air is forced into the tubes and is felt entering both ears. This act is attended with danger of carrying up fluid into the tubes and greatly aggravating the condition, unless the water from the spray has had time to drain away.