XI. D, 4 Seale: Shells of Mindanao and Sulu 251 



Rotation in working the pearl beds would be a great advan- 

 tage, as in this manner they would be more thoroughly pros- 

 pected and the old and wormy shells would be removed, thus 

 giving a yield of clean, first-class shells every five or six years. 

 But the revenues derived by the Government from this industry 

 will not warrant the expenditure necessary to pay the patrol 

 required to watch ten great beds and prevent poaching. I be- 

 lieve that it would be expedient to divide the entire area into 

 two parts, with the north and south dividing line passing through 

 Jolo, 121° east longitude, and then, alternately, to close one 

 half of the entire area for six years. The dividing line could 

 be watched from Jolo at small expense. This scheme would be 

 to the advantage of both the Government and the pearlers, in as 

 much as many more beds would be found, and after a period of 

 twelve years the grade and, therefore, the price of the Philippine 

 shells would be distinctly better. 



I was unable to locate any particular place where the pearl 

 beds had been excessively injured by natural enemies such as 

 rays, skates, and other fishes. However, on some of the beds, 

 notably at Jolo and Pilas, there were numerous starfishes, and 

 these undoubtedly devour many of the young oysters. 



CULTURAL PEARLS AND PEARL FARMING 



The Japanese are the only people who have made a commercial 

 success of growing cultural pearls. The method is to insert 

 some foreign body into the shell of the living oyster; this body 

 is covered by layers of pearly nacre, and thus forms the cultural 

 pearl. However, the method of growing quantities qf round 

 pearls of as good a luster and shape as those found in nature 

 was perfected only during the past two years by Professor 

 Fujita, of the Imperial University at Tokyo. I submitted some 

 of these pearls to jewelers in Manila, and they were unable to 

 distinguish them from natural pearls. 



DESCRIPTION OF THE INTENDED EXPERIMENT OF PEARL PRODUCTION IN THE 

 PHILIPPINE ISLANDS ' 



Originally the term "culture pearl" was applied by Mr. Miki- 

 moto to a hemispherical blister formed over a foreign body 

 artificially inserted between the shell and mantle of a pearl 

 oyster. 



'We are fortunately able to include under this heading some comments 

 on the production of cultural pearls, which were kindly furnished by 

 Professor Fujita himself. — Editor. 



