HEARING. 607 
have a fundamental (self-tone, proper tone) tone of their own, 
to which they respond more readily than to others. 
If such held for the membrana tympani, it is evident that 
certain tones would be heard better than others, and that when 
the fundamental one was produced the result might be a sen- 
sation unpleasant from itsintensity. This is partially obviated 
by the damping effect of the auditory ossicles, which also pre- 
vent after-vibrations. 
Some suppose that what we denominate shrill or harsh 
sounds are, in part at least, owing to the auditory meatus hav- 
ing a corresponding fundamental note of its own. 
The Auditory Ossicles— Though these small bones are con- 
nected by perfect joints, permitting a certain amount of play 
upon one another, experiment has shown that they vibrate in 
response to the movements of the drum-head en masse ; though 
Fie. 447.—Section of auditory organ of horse (after Chauveau). A, auditory canal; B, mem- 
brana tympani; C, malleus; D, incus; F, stapes; G, mastoid cells; H, fenestra ovalis ; 
I, vestibule ; J, K, Z, outline of semicircular canals; M, cochlea; N, commencement of 
scala tympani. 
