Fish 



383 



ments. They make the best of buttons, neat and dura- 

 ble and beautiful, a great improvement over the buttons 

 of wood and metal formerly in use. The annual 

 product of pearl buttons from this source is now worth 

 many millions of dollars. It is all derived from wild 



FIG. 230. Valve of a mussel shell, with "blanks" cut from it, 

 in process of manufacture into pearl buttons. 



mussels; the method in use is exploitation, not hus- 

 bandry. 



Fish- -The great staple food product of the water is 

 fish. In our day frogs are used but locally and fresh 

 water crustaceans and other animals, hardly at all; 

 but fishes are used everywhere. They have been a 

 staple food from the beginning of human history, and 

 probably will be to the end. Hence it is that inland 



