PEARLS 209 



even during this age of insatiable and adventurous 

 search man does not secure a tithe of the ocean s tribute, 

 for, since a pearl is a source of discomfort to its host, the 

 unceasing effort of the animal is towards expulsion. The 

 greatest and possibly the most magnificent are cast out 

 as rubbish on the ocean floor, or are retained within the 

 valves when the animal dies of old age. 



So-called pearls have been found in elephants' tusks 

 and semi-adherent to the bones of fish, and concretions 

 — hard, smooth, and round, and of the flat hue of 

 skimmed milk — in coco-nuts and in the cavities of bam- 

 boos; but in the production of the real gem neither 

 oyster nor mussel nor pinna need fear the rivalry of 

 anything on the earth's surface. The pearl belongs to 

 the sea. 



Completely spherical pearls can be formed only loose 

 in the mantle or soft parts of the body of the animal ; 

 but intrusions incite a deposit of nacre in the form of a 

 projection on the interior, which projection, often a 

 mere bubble, but sometimes semi-detached, may take 

 the shape and dimensions of the foreign substance. 

 Or an inoffensive mollusc may be goaded by the piercing 

 of its shell from the exterior to create that for which 

 men venture into the depths of the sea. If a pearl- 

 secreting oyster be inherently robust, its defence against 

 assault from without may consist of the strengthening 

 of the interior at the point of attack by deposits of 

 nacre. Thus, a slight protuberance arises which 

 becomes the base of a blister or button or the starting- 

 point of a pear-shaped gem. Many a lovely gem is, 

 therefore, nothing more than the imperishable record of 

 aggression on the part of a flabby sponge on a resource- 

 ful oyster. Occasionally valuable pearls are found 

 within huge blisters. Such pearls originate, no doubt, 

 in the ordinary way, but, becoming an intolerable 



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