52 PEARLS [CH. 



The difficulties under whicli the pearl oyster lives 

 have been briefly touched upon. Finally, man him- 

 self, by his heedless removal of millions of breeding 

 oysters, is not the least of the enemies of the pearl 

 oyster, and a failure of the pearl-fishery must often 

 be attributed to his influence. 



CHAPTER Y 



PEARLS 



There is no little difficulty in making out from 

 the literature and from "common knoAvledge" what 

 is actually meant by the term "pearl." Some dic- 

 tionaries are most ambiguous on this point. For 

 example, in the same paragraph we are told that 

 a pearl is "a silvery white smooth and iridescent 

 gem, extracted from the pearl oyster"; "something- 

 round and clear, like a dewdrop"; "anything very 

 precious." No doubt the term pearl is applied to 

 many beautiful objects in poetry and literature, but 

 so far as we are concerned, the name will have to be 

 used in a more restricted sense. 



A pearl consists of a number of layers of organic 

 and inorganic matter, arranged more or less regularly 

 round some common centre (termed the nucleus) and 



