VII. CHEMISTRY AND PHARMACY.
63. State in which Morphia exists in Opium.—In the 80th article of our Quarterly Summary for January, we stated that Mr. Robinet had announced the discovery of a new acid in opium, with which the morphia was combined; while the meconic acid was alleged to be united with soda. To the former salt, he gave the name of codeate of morphia. Mr. Robiquet, however, has shown, that the pretended codeate, is a muriate of morphia, formed by double decomposition between the muriate of soda, employed by Mr. Robinet in his analysis, and meconate of morphia. The same decomposition shows the source of the meconate of soda. We observe that Mr. Robinet admits his mistake.—Archives Générales de Medicine.
64. Peculiar principles of Narcotic Plants.—"Dr. Brandes of Sabzerflen, having been prevented by extreme illness, induced by investigating the peculiar principles of narcotic plants, from completing his inquiries, has announced the results of his labours in general terms. He states, that he has found a peculiar narcotic principle in all the narcotic plants; as belladonna, hyosciamus, conium, stramonium, chelidonium, digitalis, &c. The narcotic principles are readily soluble in alcohol, ether, acids, and water, and of a highly offensive odour. This odour is so great in the principle of conium, that it is almost impossible for an individual of an irritable habit, to remain in the room, where there is an etherial solution, containing only a few grains of it. The smell of such a solution is equal to the smell, arising from twenty or thirty pounds of the plants. It is also remarkable, that as this principle is neutralized by acid, the disagreeable odour disappears, or is greatly diminished; which so far agrees with the circumstance, that the plants themselves give little of their peculiar smell, because the narcotic principle is not in a free state. Dr. Brandes has promised to communicate the manner of obtaining the principles."—Lond. Med. Repository, Feb. 1826.
65. Relative quantities of Cinchonia and Quinia in the most esteemed Varieties of Peruvian Bark.—Mr. Bally asserts, that practitioners, from observation, have classed the Peruvian barks in the following order;—first, the gray loxa bark, (Cinchona Officinalis;) then the red bark (Cinchona Magnifolia of Ruiz and Pavon, or Oblongifolia of Mutis;) and lastly the yellow bark, or calisaya, (Cinchona Cordifolia of Mutis, or pubescens of Valli.) The Cinchona Officinalis furnishes much cinchonia, and little quinia; the Cinchona Magnifolia affords about equal quantities of the two salifiable principles, while the Cordifolia contain much quinia.
Mr. Bally, assuming it as proved, that cinchonia is the more powerful salifiable base of the two in a medical point of view, considers, therefore, that, in regard to the above barks, chemical analysis justifies the order of their relative value, which had been previously deduced from their medical employment.—Archives Generales de Medecine.
66. Sulphate of Quinia, extracted from the Cinchona Bark, exhausted by Decoction.—Mr. Julia-Fontenelle, from the sparing solubility of quinia and cinchonia, suspected that decoctions and aqueous extracts of Peruvian bark contained but little of those vegetable alkalies; whence it would follow, that the residuum, generally rejected as having no febrifuge power, would still contain the greater part of them. This suspicion has been in a great measure verified. The aqueous extract was found to contain but little cinchonia and quinia; while the residuum of decoctions, giving the mean results, furnished two-thirds of the sulphate of quinia, yielded by the same weight of cinchona not acted on by water.
As decoctions and aqueous extracts of bark are febrifuge, though containing inconsiderable quantities of quinia, and cinchonia, Mr. Julia-Fontenelle is led to believe, that these salifiable bases are not the only febrifuge principles in Peruvian bark, but that the extractive matter also possesses that property.
His results present a striking difference between alcoholic and aqueous extracts of bark; for while the former contain nearly the whole of the salifiable principles, the latter contain very little.—Revue Medicale.
67. Analysis of Rhubarb.—It is some time since Mr. Nani, an Italian chemist, announced the discovery of a crystallizable vegetable alkali in rhubarb. Mr. Caventou has repeated the experiments of Mr. N. and finds them, in many respects, inaccurate. Upon analysing the alcoholic extract of rhubarb, by the aid of alcohol and ether, employed separately and combined, Mr. C. obtained a fatty matter, containing a little odoriferous volatile oil, and a yellow colouring principle, capable of crystallization, and of being sublimed without decomposition, which may be called rhubarbin. He also detected in the alcoholic extract, a brown substance, insoluble in water when pure, but rendered soluble by combination with rhubarbin; when it forms a compound, constituting the eaphopicrite of some chemists, and the rhubarbin of Psaff.—Archives Generales.
Mr. George W. Carpenter, of this city, prepares the medicinal principle of rhubarb in combination with sulphuric acid, under the name of sulphate of rhubarb, by the following process: