THE EAR. 507 



THE ANATOMY OF THE EAR. 



The sense of hearing has, of course, from time imme- 

 morial been attributed to the ear, and some explanations as 

 to the manner in which 'hearing occurred were advanced 

 with fair accuracy by very early writers. It was, however, 

 reserved for the last decade to very materially advance our 

 knowledge. It was impossible to understand the percep- 

 tion of musical sounds until Corti, in 1846, worked out 

 carefully the anatomy of the cochlea, and especially the 

 membranous cochlea. The rods of Corti bear this observer's 

 name. The finer anatomy of the vestibule and the ampullae 

 was understood when the work of Max Schultze on these 

 structures was published in 1850. In 1842 the physiologist 

 Florens, and in 1869 Goltz advanced the idea that the semi- 

 circular canals were not directly concerned with hearing, 

 but were organs of equilibrium. It was, however, reserved 

 for Helmholtz to study with the greatest care the individual 

 parts of the ear, and to him we are indebted largely for the 

 present conception we have of the function of that organ, 

 as well as for the theory of harmony in terms of which the 

 various phenomena of musical sounds are ext>lained. 



THE EXTERNAL EAR. 



The external ear is composed of the outer shell of the 

 ear called the concha, and the opening leading to the tym- 

 panic membrane designated as the auditory meatus. 



1. Concha. The concha consists mainly of elastic 

 cartilage and serves to collect the sound like a funnel and 

 direct it into the auditory meatus. As such a collector of 

 sound it is, however, very deficient in human beings. The 

 external ear may be entirely removed without apparently 

 interfering with the acuteness of hearing. In the lower ani- 

 mals its efficiency as a collector is unquestioned. In these 

 animals it is relatively much greater, is more definitely 

 funnel-shaped, and is movable in such a way that it may be 

 placed in the most advantageous position in gathering the 

 sound. In the human ear it has lost most of these proper- 



