HEARING. 



the eyeball, and they keep it moist. What remains is 

 drained off by canals which run from the inner corner 

 of each eyelid to the inside of the nose, from which the 

 liquid flows into the pharynx, and is swallowed. In 

 weeping, the tears are secreted faster than these canals 



FIG. 58. Semi-diagrammatic section through the right ear. M, concha. G. ex- 

 ternal auditory meatus. 7", tympanic or drum membrane. P, Tympanum. Ex- 

 tending from T to o is seen the chain of tympanic bones. /?, Eustachian tube. 

 K, B, S, bony labyrinth: V, vestibule; B, semicircular canal; S, cochlea, b, I, /', 

 membranous semicircular canal and vestibule. A, auditory nerve dividing into 

 branches for vestibule, semicircular canal, and cochlea. 



can carry them off, so they flow over the lower eyelids 

 and trickle down the face. 



12. Hearing. The ear consists of three portions, known 

 as the external ear, the middle ear or tympanum (drum), and 

 the internal ear or labyrinth. The labyrinth is so named 



are they spread over the eye ? Where are they usually carried from 

 the eye? Why do they trickle down the face in weeping? 



12. What are the three main portions of the ear? Why is the 



