CHAPTER 19 



Miscellaneous Industrial Products 



Maurice E. Stansby 



Several industrial products are prepared from fish which have not been 

 discussed in other chapters. These include those prepared from shell, 

 scales, skin, and bones. While these products are individually of relatively 

 minor importance, in the aggregate their value is considerable. 



Products from Scale and Shell 



A number of uses are made of the scales and shells of fish. The shell is 

 used to prepare ornamental items and buttons. The scales can be used for 

 preparing a meal for poultry feeding or as a source of pearl essence. 



Pearl Essence. Pearl essence is a solution of guanine crystals which is 

 used as a spray or dip for numerous items to give them an irridescent 

 sheen reminiscent of pearls. Such diverse articles as beads, shoes, pencils, 

 fishing rods, artificial flowers, ash trays, vanity cases, book covers, and 

 finishes for textiles employ pearl essence treatment. The largest use is for 

 the preparation of artificial pearl beads. 



Pearl essence is usually composited as an eleven per cent suspension in 

 a solvent or lacquer of guanine crystals obtained from fish (usually her- 

 ring) scales. 



Pearl essence preparation from fish scales has been an art since the 

 fifteenth century^, and the chemical basis for the effect has been known 

 since the late nineteenth century^. In the United States herring from the 

 New England sardine fishery furnish the scales for operation of several 



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