THE SKIN. 169 



are made to vibrate. The last one in the chain, the stirrup, 

 is joined to a small membrane in the inner wall of the 

 drum, which is like a little drum-head. On the other side 

 of this little drum-head is the inner ear, which is filled 

 with water. As the stirrup vibrates, it sets the little 

 drum-head vibrating; and that makes the water in the 

 inner ear vibrate, and the little waves strike the ends of 

 the nerve of hearing, and by it the impression is carried 

 in to the brain. 



9, It is not the ear that hears. It is the brain that 

 hears by means of the ear. 



7, An ear-ache is commonly caused by inflammation of 

 the lining of the drum. It swells, and discharges a fluid 

 that fills the cavity, and makes pain by pressure. Some- 

 times, as the inflammation subsides, the fluid is absorbed. 

 Sometimes the drum-membrane bursts, and lets out the 

 fluid ; and the pain stops. A discharge from the ear com- 

 monly comes from an inflamed middle ear through a hole 

 in the drum-head. If the hole is small, it may heal up 

 when the discharge stops. If a large part of the drum- 

 membrane is gone, it will not heal up. 



8, The loss of the drum-head does not destroy the hear- 

 ing, but it impairs it. 



9, Ear-iuax is made by glands in the skin lining the 

 auditory canal. It is not a safe practice to dig it out with 

 hair-pins or other instruments. Ear-wax is necessary to 

 keep the canal and drum-head soft and moist, and it will 

 take care of itself. If it forms hard lumps, and stops the 

 ear, as it sometimes does, it may be removed by syringing 

 with warm water. No one but a physician should put in 

 any instrument. 



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