86 THE BEAUTIES OF NATURE CHAP. 
another. It has been supposed that they 
enable us to maintain the equilibrium of the 
body, but no satisfactory explanation of: their 
function has yet been given. In the cochlea, 
Corti discovered a remarkable organ consist- 
ing of some four thousand complex arches, 
which increase regularly in length and dimin- 
ish in height. They are connected at one end 
with the fibres of the auditory nerve, and 
Helmholtz has suggested that the waves of 
sound play on them, like the fingers of a per- 
former on the keys of a piano, each separate 
arch corresponding to a different sound. We 
thus obtain a glimpse, though but a glimpse, 
of the manner in which perhaps we hear; but 
when we pass on to the senses of smell and 
taste, all we know is that the extreme nerve 
fibres terminate in certain cells which differ 
in form from those of the general surface ; 
but in what manner the innumerable differ- 
ences of taste or smell are communicated to 
the brain, we are absolutely ignorant. 
If then we know so little about ourselves, 
no wonder that with reference to other ani- 
mals our ignorance is extreme. 
