THE OYSTER. 23 



covered by layer after layer of pearl. It has been 

 shown that, in some cases at least, the nucleus of a pearl 

 is the dead body of a microscopic parasite of the 

 mollusc. The brilliant lustre, as well as that of mother- 

 of-pearl, which is nothing but polished shell, is due to 

 the interference of light caused by the laminated struc- 

 ture. 



It is said that the Chinese manufacture pearls, or 

 rather make the pearl oyster do the work for them, by 

 inserting strings of small shot between the shell and 

 the mantle. Did you ever see one of the sacred clam 

 shells which the Chinese Buddhists believe to have a 

 miraculous origin? They are often found in collec- 

 tions. The inside of the shell has a beautiful pearl 

 lustre, and along it is a row of little fat images of 

 Buddha, squatting with his legs crossed under him, 

 and his elbows on his knees : they are formed of pearl 

 precisely like that which lines the rest of the shell, a 

 little raised above its surface and outlined in faint relief, 

 but they are part of the shell, with no break nor joint. 

 In the process of manufacturing them, the shell of 

 the living animal is wedged open, and thin images, 

 punched out of a sheet . of bell-metal, are inserted. 

 The animal is then returned to the water, and is left 

 there until enough new shell has been formed to 

 cover them with a varnish of pearl thick enough to 

 fasten them, and to hide the metal, while permitting 

 the raised outline to be seen. 



Several years ago it occurred to me that a series of 

 microscopic specimens of stages in the growth of the 



