National Geographic : 1938 Jan
Photograph by W. Robert Moore PEARLS SEEN AT BRITAIN'S CORONATION AND OUR PRESIDENT'S BIRTHDAY BALLS CAME FROM THE ROCKY ISE COAST The girl divers who tend the oysters rest on the boats between plunges, their baskets floating alongside. Behind them are the rafts towhich are attached cages con taining the oysters that they nurse for many years. By careful tending and breeding, the Japanese have developed a vigorous oyster stock. Atthe age ofthree years an oyster is opened, and a tiny bead, which has been wrapped in living tissue from another oyster, is inserted. This graftedoyster isplaced inacage (toprotect itfrom star fishes, etc.) and lowered into the sea. For seven years the oyster continues making secretions around the irritating particle. Then itisopened, and the chance isone in twenty that the graft has become a lustrous pearl. The process has been developed by Kokichi Mikimoto, who now owns and operates 11"farms." He began ex periments in 1893, completed the invention and obtained perfectly spherical pearls in 1921.