FISHES. 
119 
qf the water, and he consequently sinks. On the 
contrary, when the action of the abdominal muscles 
is removed, the air-bladder acquires its natural size, 
the body is rendered more bulky, it begins to 
ascend, and with the assistance of the fins is carried 
to the surface of the water. If this bladder bursts 
within the fish he can never rise again, but must 
be content to spend the remainder of his life at the 
bottom. The fishermen know this, and take ad- 
vantage of the circumstance to preserve the cod 
alive. When they take a number of those fish, 
they run a needle into the sound, or air-bladder, 
and thus disengage the air; after which the cod 
lie very quietly at the bottom of their well-boats. 
None of the tribe of flat-fish are provided with this 
organ ; they are, therefore, obliged to remain con- 
stantly at the bottom, unless they are provided 
with very large pectoral fins, which answer the 
purpose of wings : thus the rays, by the motion of 
these fins, elevate themselves in the water precisely 
in the same manner that birds rise in the air. 
There is no doubt but fishes possess the sense of 
smelling, since the organ designed for that purpose 
is large, and capable of being contracted or dilated 
at pleasure. This sense is easily put to the proof ; 
for, if a fresh worm be thrown into the water, a fish 
will immediately distinguish and pursue it ; but if 
the same worm has remained there till it has lost 
its smell, the fish will not come near it : they may, 
however, be again attracted, if the worm be taken 
