9 o FROM AN EASY CHAIR 



neck, and lays down layer after layer of pearl substance 

 around the intrusive parasite, the dead remains of which 

 can be detected with the microscope in sections of the 

 pearl forming there a central kernel or nucleus. These 

 parasitic worms were first detected in the small pearls 

 formed by the common edible sea-mussel. 



Though they are very small, sea-mussel pearls are 

 collected for the market at Conway, in North Wales, 

 and also on the coast of France. The parasitic worm 

 is the young of a worm which, when adult, lives in the 

 intestine of carnivorous fishes. It appears that it has 

 to pass from and with the mussel into shellfish-eating 

 sea fishes, where, although the mussel is digested, the 

 parasite is not, but grows in size and alters its shape 

 considerably. Then after a time the worm is swallowed, 

 with the fish in which it has fixed itself, by sharks, dog- 

 fish, and such fish-eating fishes. In these at last it 

 becomes adult and of some size, an inch or so long, 

 varying according to the particular kind, and produces 

 many thousands of eggs, which hatch out as minute 

 creatures swimming in the sea-water, and fortunate if 

 they fall upon a bed of mussels. They enter the 

 mussel's shell and make their way into its soft substance. 

 A certain number (very few) get encased in the skin 

 and covered up by pearl-layers, which is the mussel's 

 way of killing them and putting them out of mischief. 

 The others which have entered other regions of the 

 mussel's body thrive, and have a chance of being swal- 

 lowed by a mussel-eating fish, and then a further chance 

 of that fish being eaten by a shark. If this happens 

 the lucky worm like the Italian who gets a winning 

 number in three successive drawings of a lottery- 

 gains the big prize. He becomes adult and produces 

 innumerable young, who in their turn enter upon the 

 chanceful career of a mussel parasite. 



Thus we see that a pearl is not only a disease or 

 abnormal growth caused by a parasite, out is actually 



