NATURAL HISTORY. 



rapidly as possible, tearing the oysters loose with his hands and placing 

 them in the basket. When his breath is almost exhausted he jerks the 

 rope as a signal, and is quickly drawn to the surface, where, sitting on 

 fch e r ai] of the boat, he rests while another is down. The depth at which 

 the oysters occur varies between eight and thirteen fathoms, ten being 

 perhaps the average. The pressure of the water even at this depth is 

 very great, and upon first entering upon the life of a diver, the blood 

 usually gushes from mouth and nostrils when one is drawn from the 

 water. This failing is gradually overcome, and a constant life of this sort 

 soon renders the divers able to stay below for an almost incredible space of 

 time. It also produces another effect, — it ruins the health and brings on 



an early death. 



One of the fishing-boats will hold about sixty thousand shells, and 

 when it is full it stands in for the shore, and discharges its cargo. On the 

 shore are the yards or pens where the oysters are allowed to die and 

 di 'compose. These pens are quadrangular, and have a low earthen wall 

 about them and a floor of beaten earth. Placed here, the oysters soon die, 

 the operation being sometimes hastened by drenching them with fresh 

 water. Soon decomposition begins, and then the whole decaying mass of 

 flesh is carefully examined to see if there be any pearls loose in it, for 

 these loose pearls are more apt to be perfect than those which adhere to 

 the shell. After the flesh is disposed of, the shells are examined, and any 

 pearls adhering to them are broken off with forceps. This of course makes 

 a blemish, but the fractured surface is finished carefully with fine files, and 

 then the pearl can be used in a setting without the flaw showing. Lastly, 

 the whole floor of the pen is carefully examined, to see if any pearls may 

 have fallen from the shells. The stench arising from these pens under the 

 rays of a tropical sun is beyond description. 



1 1, iv. on the north shore of Ceylon, the pearl fishery has been carried 

 on almosl exactly as to-day for two thousand years, and no one knows 

 how much longer. For miles the shore is covered to an average depth of 

 tour or five feet with the dead shells of the pearl-oyster, and still the 

 deposit goes on. 



Pearls are abnormal products. Under normal circumstances the outer 

 surface of the mantle secretes a nacreous shell, which is added to the shell 

 already formed; but when a grain of sand, a parasitic worm, an egg, or 

 some other foreign body gets between the mantle and the shell, it receives 

 the secretion, which is probably stimulated by the irritation, and so in- 

 creases rapidly. 



The value of a pearl, like that of any precious stone, depends on sev- 

 eral elements, — shape, color, size, etc. The finest pearls rarely exceed a 



