1 62 LECTURE XI T . 



One of the organs most necessary "to fish in 

 swimming is the bladder of air in their stomach, 

 by means of which they can make their bodies 

 more or less heavy. Thus, when the air- 

 bladder swells and extends, they become lighter, 

 and can swim to the surface of the water, and 

 when it contracts and the air is compressed, 

 the body is heavier than the water, and con- 

 sequently sinks down. You see how admirably 

 everything is adapted for the element in which 

 it moves. 



And here I may mention that when the Dogger- 

 bank fishermen capture a cod, they immediately 

 puncture a hole under the dorsal, or breast-fin, 

 with an instrument something like a shoemaker's 

 awl, and thus let the air out of the bladder. 

 The fish is then transferred to a well under 

 the fishing-boat, where it remains, with many 

 others, incapable of motion, till her cargo is 

 completed, when the vessel sails for England. 

 On arriving in the Thames, it remains a short 

 time in brinish water, and then is taken to the 

 fresh water of Billingsgate, where the fish are 

 sold as they are wanted. By looking at a 

 Doggerbank cod in Mr. Hayllar's well-stocked 



