PEARL FISAERY AT CEYLON'. 409 



extravafations may be caufed by heterogeneous bodies 

 inch as land, coming in with the food, which the ani- 

 mal, to prevent difagreeable friction, covers with its 

 glutinous matter, and which as it is fucceffively fecreted 

 forms many regular lamellae, in the manner of the 

 coats of an onion, or like different it rata of bezoars, 

 only much thinner ; this is probable, for if we cut 

 through the centre of a pearl, we often find a foreign 

 particle, which ought to be confldered as the nucleus, 

 or primary caufe of its formation.' The loofe pearls, 

 may originally have been produced within the body, 

 and on their encreafe may have ieparated and fallen 

 into the cavity of the fhell. Thofe compact ones, 

 fixed to the fhells feem to be produced by limilar ex- 

 travaiation, occafioned by the friction of fome rough- 

 nefs on the infide of the fhell. Thefe and the pearl- 

 like nodes have a different afpect from the pearls, and 

 are of a darker and bluer colour. In one of the former 

 I found a pretty large, true oval pearl, of a very clear 

 water ; while the node itlelf was of a dark blueifh co- 

 lour. The yellow or gold coloured pearl, is the mod 

 efteemed by the natives ; fome have a bright, red, luf- 

 trc ; others are grey or blackiih, without any fhining 

 appearance, and of no value. Sometimes when the grey 

 lamella of a pearl is taken off, under it is found a 

 beautiful genuine one, but itoftener happens that af- 

 ter having Ieparated the firft coat you find a worthlels 

 impure pearl. I tried feveral of them, taking one la- 

 mella off after another, and found clear and impure 

 by turns, and in an impure pearl 1 met with one of a 

 clear water, though in the centre of ail I found a fo- 

 reign particle. The largeft and moft perfect pearl 

 which I law during inv ilav at Condatrhty. was about 

 the fize of afmall piftol bullet, though I have been 

 told fince my departure, many others of the fame 

 fize have been found. The fpotted and irregular 

 ones are fold cheap, and are chiefly ufed by the na- 

 tive phyficians as an ingredient in their medicines. 



Vol. V.. C c We 



