48 
LECTURE VIII. 
called the crystalline humour, is of a round or glo- 
bular shape, in order to give the animal the ne- 
cessary pov^er of vision, and to compensate for 
the comparative flatness of the cornea. 
The organ of smelling in fishes is large, and 
the animals have the power of contracting or di- 
lating the passage to it at pleasure. Their smell 
is supposed to be extremely acute. 
It was formerly much doubted whether fishes 
possessed the sense of hearing, having no external 
ear : the accurate researches of modern anatomists 
have however clearly evinced that the organ of 
hearing, tlioiigli difl'ering in some particulars from 
that of other animals, does yet exist ; and is only 
modified according to the different nature of the 
animals. Indeed although the nature of the organ 
of hearing in fishes was not accurately known to the 
older anatomists, yet it was plain that fishes did 
hear; as was evident from a practice common 
in many jiarts of Europe of calling Carp and other 
fishes to their feeding-place by the sound of a 
bell; a signal which the animals readily obey. 
The particular structure of the Ear in fishes may 
be found amply explained in the works of Monro, 
Cuvier, Camper, and other modern anatomists. 
Of voice, properly so called, fishes are en- 
