PEARLS AND IMITATION PEARLS 115 



stands as a separate layer on top. When the con- 

 tainer is gently rocked, the lustrous crystals pass 

 from the water into the ether layer, leaving all dirt, 

 organic matter, and the like in the water. Any fatty 

 or waxy substances dissolve in the ether, but these 

 may be removed by allowing the crystals to settle out, 

 decanting the oily ether, and replacing it with clean 

 anhydrous ether. The lustrous crystals are now clean 

 and brilliant, and can be kept indefinitely in the 

 ether or can be easily transferred to ethyl or amyl 

 acetate. Nitrocellulose or cellulose acetate may be 

 dissolved in these solvents, thus forming a pearl 

 lacquer, which is applied directly to the bead. 



While essence d'Orient may be prepared in unlim- 

 ited quantities from fish scales, yet it could probably 

 be prepared at a lesser cost from synthetic guanine. 



Pearl essence is used in the manufacture of many 

 ornaments other than imitation pearls. Buckles, hat- 

 pins, stick-pins, watch-fobs, and many other objects 

 are often ornamented with this, the most beautiful 

 lacquer. It adds a novel luster to transparent cel- 

 luloid and bakelite articles. If it were a little cheaper 

 it would find many uses in household decoration. 



Glass beads are also covered with the swim-blad- 

 der membrane from certain fishe's, thus producing 

 the so-called Roman pearls. The swim-bladders of 

 fish are composed chiefly of collagen containing a 

 brilliant natural deposit of guanine crystals. Their 

 principal use is in the preparation of isinglass, but 

 the air bladder of the European smelt (Argentina 

 sphyrcena) is used in the covering of beads in the 

 manufacture of Roman pearls. 



