31. _Preparation of Morphia_.—Some curious experiments have been described to the Académie de Médecine, by M. Robinet, relative to the preparation of morphia. Having operated on the residue of opium by muriatic acid, and precipitated the morphia from the muriatic solution by lime, he wished to ascertain whether the mother liquor contained any morphia that had escaped precipitation. He, therefore, passed a current of carbonic acid gas through the solution, to precipitate the lime in excess: this precipitate being washed, dried, and acted upon by alcohol, was found mixed with a very large proportion of morphia, which could [p217] be thus separated. The washings of the precipitate being examined, were found free from morphia.
M. Henry observed, at the same time, that, from experiments made at La Pharmacie Centrale, it appeared that much more morphia was obtained in those processes in which lime had been used to precipitate the morphia, than in those in which magnesia had been used.—_Bull. Univ._ C. xi. 225.
32. _Easy Method of obtaining Meconic Acid_, by Dr. Hare.—If to an aqueous infusion of opium we add subacetate of lead, a copious precipitation of meconiate of lead ensues: this being collected by a filter, and exposed to sulphuretted hydrogen, meconic acid is liberated: the solution is of a reddish amber colour, and furnishes, by evaporation, crystals of the same hue. A very small quantity produces a very striking effect in reddening solution of peroxide of iron. Instead of sulphuretted hydrogen, sulphuric acid may be used to liberate the meconic acid: the presence of the former in excess does not seem to interfere with the power of reddening ferruginous solutions, but any excess of sulphuric acid may be removed by whitening, which is not acted upon sensibly by meconic acid; Yet, the acid procured in this way did not crystallize so handsomely, or with so much facility, as that obtained by sulphuretted hydrogen.
33. _On a New Vegetable Acid_.—This acid is crystallizable, but the forms have not as yet been determined: it is less soluble in cold water than tartaric acid; its aqueous solution precipitates lime water in white floculi, just like tartaric acid, but the precipitate, if dissolved in muriatic acid, re-appears on adding ammonia, whilst that produced by tartaric acid does not produce this effect. The new acid has a greater affinity for lime than muriatic or nitric acids, for it precipitates the muriate and nitrate of this earth in the manner of oxalic acid, but it differs from the latter in not precipitating a solution of sulphate of lime. With potash it forms an acid salt, slightly soluble in cold water: it precipitates acetate of lead, and the precipitate holds much water in combination: the tartrate of lead, on the contrary, is anhydrous. Notwithstanding these circumstances, the equivalent number of this acid is within a few thousandths of that of tartaric acid: when distilled, it is decomposed, and produces an acid yellow liquid like tartaric acid, leaving a light charcoal burning without residuum. M. Gay Lussac is engaged in developing the chemical history of this substance.—_Bull. Univ._ A. vii. 327.