546 



THE POPULAR SCIENCE MONTHLY 



The Concrete Live-box above Water at Low Tide. 



inoculating the edible mussel, Mytilus, by placing it with parasitically 

 infected mollusks and thus artificially induced the formation of pearls. 

 Herdman, in 1903, found in the pearl-oysters of Ceylon that a tape- 

 worm larval cyst may become a pearl nucleus, or that in some cases the 

 secretions may he deposited around sand grains, bits of mud or a fish 

 or some other small animal, in pockets of the mantle epidermis, or again 

 about calco-spherules near the muscle insertions. The surface finally 

 becomes polished, or takes the " orient," and thus reflects the opaline 

 and nacreous tints so highly prized. 



The production of culture pearls dates back to the fourteenth cen- 

 tury in China and it is probable that the Arabs had a similar industry. 

 The Chinese open the shell of the river-mussel, push back the mantle 

 and introduce metal images of Buddah which are covered with nacre 

 in the course of six months. Linne drilled a hole through the shell 

 and inserted a pellet of limestone on the end of a silver wire so that 

 the nucleus might be kept free from the shell during the secretion of 

 nacre. In more recent times the secretion of culture pearls has been 

 induced in pearl-oysters by similar methods in various countries. 

 Bouton, in 1897, at Boscoff, France, bored small holes through the 

 shell of the abalone and inserted forms made of mother-of-pearl. After 



