274 INTRODUCTION TO CONCHOLOGY. 



case, they have been undoubtedly rejected from the stomach 

 of the animal,, and have fallen into the cavity of the shell ; 

 whilst such as are fixed, most probably owe their origin to 

 some internal roughness. 



The observation of this curious fact most probably sug- 

 gested the first idea of forcing the Avicida to produce pearls. 

 It was known in the first centuries of the Christian era, and 

 acted on by the ancient people who inhabited the coasts of 

 the Red Sea, as we are informed by the philosopher Apollo- 

 nius. " The Indians," said he, '' dived into the sea after 

 they had rendered it calm, and perhaps clearer, by the 

 pouring in of oil ; they then induced the Mussels, by means 

 of some attractive baits, to expand their shells, and having 

 pricked them with a sharp-pointed instrument, the liquor 

 which exuded from the wound was received into a perforated 

 iron, where it hardened gradually, and formed pearls of the 

 finest water.'''' 



Modern naturalists are undecided with regard to the 

 accuracy of this narration ; yet there are various reasons 

 to conclude, that the people who lived on the shores of the 

 Red Sea were acquainted with an artificial mode of pro- 

 duciDg pearls ; and this opinion is additionally confirmed 

 by the method now in use among the modern Chinese, who 



