238 THE EEASO WHY. 



" Doth not the ear try words ? and the mouth taste his meat." JOB xn, 



987. Why is wax secreted at the entrance of the ear? 



Because, by the peculiar resinous property which it possesses, it 

 improves the sound-conducting power of the auditory canal through 

 which it prevails. 



Fig. 63. THE STRUCTURE OP THE EAR. 



A A. G lands which secrete wax in the walls of the tube of the ear. 



B. The membrane of the tympanum, or drum of the ear, formed in the shaj o 

 of a funnel. 



C C. Bones which act as a sort of sounding-board to the ear, giving strength to 

 the vibrations. 



D. The Eustachian tube, which opens into the root of the mouth, and which 

 serves to p reserve an equilibrium in the density of the air occupying the tubes 

 of the ear. 



E and F The labrynth of the ear, consisting of folds of membraneous tubes, 

 filled with fluid, which serves to undulate with the vibrations of the tympanum, 

 and thu s gives clearness and precision to the sounds. 



The auditory nerves are distributed in the tubes above described (the vestibule 

 and the cochlea E F), and the nerves receive their impressions from the undu- 

 ations of the fluid. 



983. W hy do we sometimes hear singing noises in the ear ? 

 Because the ear is liable to inflammation from various causes, and 



