190 UTILIZATION OF MINUTE LIFE. 



time, and has become decomposed at its surface ; 

 the same is likewise seen on the feathers of humming 

 birds, parrots, etc., and in certain chemical pre- 

 parations.* It is too complicated a subject to be 

 discussed here. 



Up to the present time no attempt has been 

 made to cultivate, to propagate artificially, or to 

 acclimatize in other seas, the pearl oyster of Ceylon. 

 To give an idea to what extent the pearl fishery is 

 prosecuted at the present time, I will quote a pas- 

 sage from the " Colombo Observer/' (1858), which 

 is as follows : 



" A letter of the 20th March states ' We have 

 had ten days' fishing, and there is about 15,000 

 already in the chest. There will be ten days' more 

 fishing. Oysters sold to-day as high as twenty-five 

 rupees per thousand." 



The shell of Avicula margantifera is imported 

 to Liverpool from the East Indies, Panama, and 

 Manilla, at the average rate of 490 tons per annum. 

 Pearls are frequently imported from the East Indies, 

 but there is no account kept of the quantity. 



It is not unusual to find small pearls in the common 

 edible mussel (Mytilus edulis), but they are seldom 

 large enough to be of any value. It might, perhaps, 



* I have discovered that most substances possess this property, 

 when they are viewed in a proper direction in the sunshine. Polished 

 iron, ebony, and other descriptions of hard wood, possess it to a 

 remarkable degree. 



