GUMLACORSHELLAC. 37 



than the stick lac, sometimes scarcely coloring it at all. It is 

 occasionally mixed with small fragments of the twigs. 



"Shell lac is prepared by melting the stick or seed lac previously 

 deprived of its soluble coloring matter, straining it, and pouring 

 it upon a flat smooth surface to harden. It is in thin fragment.; 

 of various sizes, from half a line to a line thick, often somewhat 

 curved, of a lighter or darker brown color, inclining more oi 

 less to red or yellow, shining, more or less transparent, hard and 

 brittle, inodorous and insipid ; insoluble in water, but easily and 

 almost entirely soluble in alcohol, especially with the aid of 

 heat. 



"A variety of lac is mentioned by writers in the form of cakes, 

 called cake or lump lac (lacca in placentis,) but this is at present 

 rare in commerce. 



" According to John, lac consists of resin, coloring matter, a 

 peculiar principle insoluble in alcohol, ether, or water, called 

 laccin, a little wax, and various saline matters in small propor- 

 tion. The resin, according to Unverderben, consists of several 

 distinct resinous principles, differing in their solubility in alcohol 

 and ether. The laccin is nearly or quite wanting in the shell 

 lac, which also contains scarcely any of the coloring principle. 

 Mr. Flachet found in stick lac 68 per cent, of resin, and 10 of 

 coloring matter; in seed lac 88.5 per cent, of resin and 2.5 of 

 coloring matter ; in shell lac 90.9 per cent, of resin and 0.5 of 

 coloring matter. The other constituents, according to this 

 chemist, are wax and gluten, besides foreign matters. 



"Lac, in its crude state, is slightly astringent, and was formerly 

 used in medicine. At present it is not employed. Shell lac is 

 wholly inert. Stick lac and seed lac are used on account ot 

 the coloring principle which they contain. Shell lac, as well 

 as the other varieties, deprived of their coloring matter, is ap- 

 plied to numerous purposes in the arts. It is the chief constitu- 

 ent of sealing-wax. The best red sealing-wax is made by melting 

 together, with a very gentle heat, 48 parts of shell lac, 19 oi 

 Venice turpentine, and one of balsam of Peru, and mixing with 

 the melted mass 32 parts of finely powdered cinnabar. But 



