HAYNBS : NOTES ON PEARL FORMATION. 



223 



taken from the mantle of a living oyster and formed into a little 

 sac within which a bead of mother-of-pearl is inserted, the sac 

 tied up and inserted into an incision made in a second oyster, 

 the ligature being then removed, the wound treated with an anti- 

 septic and an astringent, and the oyster returned to the sea. They 

 are operated on when 3 years old, and opened for the result at 

 7 years, the maximum age being about 10 years. This artificial, 

 grafted sac is in imitation of the cyst which experts declare 

 is naturally made round the micleus of all fine pearls. Obviously 

 the artificial sac must be an inferior production to that formed by 

 nature, and this would account for the irregularity of the con- 

 centric layers of pearly matter compared with the remarkable 

 regularity shown in Fig. 7. 



Section ( x 11) of a ver3' perfect pearl, reproduced by the 

 kind permission of its possessor, Mr. J. G. Bradbury. 



There is no particular reason why an operation successful in 

 making 7 grain pearls in the Japanese small 3-inch pearl oyster 

 should not be adopted on the large Australian pearl oyster running 

 up to 15 inches in diameter and producing pearls exceeding even 

 100 grains ; but Mr. Mikimoto must improve his methods greatly 

 before he can produce anything in the shape of a perfectly round 

 pearl of say 40 grains, for which as much as £5,000 has frequently 

 been paid. The deviation from the true spherical shape in the 

 5 grain (Fig. 6) would be of very serious detriment in a 40 grain pearl, 

 which to fetch any fancy price must roll perfectly straight without 

 wobbling a hair's breadth. (Cf. Text figure.) 



