Notice of some recent additions to Chemistry. 75 



M. Bizio of Venice has lately, in a communication to the French 

 Academy, (L'Institut, 466,) given a description of the shells which 

 supply the Tyrian purple, a dye of great celebrity among the ancients, 

 and has sent specimens of these shells to the same society, along with 

 a quantity of the fluid procured from the shells. The Tyrian purple 

 is contained in the Murex Brandaris ; the Amethyst purple in the 

 Murex Trunculus; two shells which are very abundant on the shores 

 of the Mediterranean. The liquid is contained in a large bag which is 

 situated at the upper part of the animal, and may be extracted with 

 great facility. All that is necessary is to break the shell with a 

 hammer, and express the liquid from the bag by means of a spatula. 

 The Roman dyers break the shells in their oil mills. The liquid, which 

 is white and milky in the bag, oxidizes in contact with the air and 

 light, and passes through all the shades of green to a more or less deep 

 red. M. Bizio suggests that the dye should be tried at the Gobelin 

 establishment in Paris. The same remark might bo taken advantage 

 of in Glasgow, where the communications with the Mediterranean are 

 sufficiently frequent 



Lithofellic acid was obtained from a calculus by Gobel of Dorpat, 

 and has since been examined by Will, Ettling, and Wohler. 

 Houmann inferred that it was a constituent of bezoars or calculi 

 obtained from animals probably of the deer tribe, although this fact 

 has not been perfectly ascertained. Fourcroy and Vauquelin exam- 

 ined bezoars, and describe them as being soluble in alcohol, and 

 separating in crystals as the solution cools. They concluded that the 

 crystals consisted partly of bile, and partly of resin. These chemists 

 may be said, therefore, to have first noticed this new acid, for Goebel 

 did not any more than they analyse it Ettling and Will first 

 determined this essential point of distinction. While examining the 

 calculi in the Hunterian museum of the University of Glasgow 

 lately, four specimens of lithofellic calculi were detected. Half of 

 ono of these containing a date stone as a nucleus, is about \^ inch 

 long, r3^ inch broad, and weighs 71 grains. Half of another measures 

 \f^ inch long, ly\y inch broad, weighs 169 grains, and contains a 

 nucleus of hair and vegetable fibres. They are formed of alternate 

 brown and yellow layers ; they dissolve in alcohol and pyroxylic spirit, 

 leaving a yellow flocky matter. From a fragment of one of them we 

 extracted lithofellic acid by the following process, in the University 

 laboratory: the fragment was boiled with spirits, the solution evapor- 

 ated, and digested with caustic soda, which dissolved the whole of it 

 The alkaline solution was precipitated by muriatic acid, when a white 

 resinous precipitate fell possessing great ductility and adhesiveness. 

 The precipitate was well washed and dissolved in alcohol. By repeated 



