[465]. Sulphate of Quina. As this preparation is considered the most active form of the salifiable principle of bark, I have subjoined the most approved formula for its preparation. Boil for half an hour two pounds of the appropriate bark in powder, in sixteen pints of distilled water, acidulated with two fluid-ounces of sulphuric acid; strain the decoction through a linen cloth, and submit the residue to a second ebullition in a similar quantity of acidulated water; mix the decoctions, and add by small portions at a time, powdered lime, constantly stirring it to facilitate its action on the acid decoction. (Half a pound is near the quantity requisite.) When the decoction has become slightly alkaline it assumes a dark brown colour, and deposits a reddish brown flocculent precipitate, which is to be separated by passing it through a linen cloth. The precipitate, is to be washed with a little cold distilled water and dried. When dry it is to be digested in rectified spirit, with a moderate heat for some hours; the liquid is then to be decanted, and fresh portions of spirit added till it no longer acquires a bitter taste. Unite the spirituous tinctures, and distil in a water-bath till three fourths of the spirit employed has distilled over. After this operation there remains in the vessel a brown viscid substance covered by a bitter, very alkaline and milky fluid. The two products are to be separated and treated as follows. To the alkaline liquid add a sufficient quantity of sulphuric acid to saturate it; reduce it by evaporation to half the quantity; add a small portion of charcoal, and after some minutes ebullition, filter it whilst hot, and crystals of Sulphate of Quina will form. The brown mass is to be boiled in a small quantity of water, slightly acidulated with sulphuric acid, which will convert a large portion of it into Sulphate of Quina. The crystals are to be dried by bibulous paper. Two pounds of bark will, it is said, yield 5 to 6 drachms of the sulphate; of which eight grains are considered equivalent to an ounce of bark. It has been prepared in this country by several manufacturing chemists, especially by Mr. Pope of Oxford Street, whose zeal and industry in Pharmaceutic experiments entitle him to great commendation. The superior price of the bark, however, from the duty in this country, as well as that of alcohol, must prevent us from entering into competition with the French in its manufacture, and it has accordingly been found more œconomical to import, than to prepare it.
[466]. Journal de Physiologie. No. 1, p. 90.
[467]. Upon this point however a difference of opinion has existed; M. Halle entertained considerable fears on the subject, which were supported by M. M. Larrey, Emery, Duponchel, and others, who communicated to the Société Médicale d’Emulation, facts which excited their apprehensions. The question, however, has been set at rest both in this country and on the Continent. They are perfectly harmless.
[468]. Cinchonia has been detected in other vegetables besides the Bark, as in the root of Cusparia, and in the berries of Capsicum, while in the bark of Cascarilla, a substance bearing a much nearer relation in medicinal effect to the Bark, its presence has not yet been discovered. It is said that experiments have been lately made by M. M. Robiquet and Petroz on the Bark of the Carapa, which has been successfully used in several parts of America in the cure of agues, and that they have found in that bark a salifiable basis analogous to Quina.
[469]. In Brande’s Journal for January 1830, it is announced that Serturner has discovered other vegeto-alkalies in the Bark, besides the Cinchonia and Quinia.—One in particular he has ascertained, which he calls Chinioidia, existing in combination with a resinous sub-acid substance. This exists in the red and yellow bark with the Cinchonia and Quinia. It has more alkaline power and capacity of saturation, as well as greater medical power than any other vegeto-alkali in the Cinchona, but it resembles them in its insolubility in water, its colour and taste. According to Serturner, the febrifuge power of the Chinioidia is as superior to that of the Cinchonia and Quinia as these are to the Bark.—In his hands it succeeded in many cases where the Sulphate of Quinia had failed. Ed.
[470]. It was under this form that the celebrated empiric Talbor used to administer it in the paroxysms of Intermittents, and so successful was his practice, that Louis XIV. was induced to purchase at a large price the secret of his specific; and Charles the Second very unjustly protected him against the power of the College, and appointed him one of his physicians.
[471]. Mr. Thompson has suggested the probability of this circumstance having arisen from the admixture of a species of bark, lately introduced into Europe from Martinique, resembling the Cinchona Floribunda, and which, by an analysis of M. Cadet, was found to contain iron. (London Disp. Edit. 3. p. 247.)
[472]. This plant is found in abundance in Piedmont, principally in the marshes, where of course it is most needed. Nature is very kind in this respect, for the particular situation which engenders endemic diseases, is generally congenial to the growth of the plants that operate as antidotes to them.
[473]. Dr. Davy, in a letter to me upon this subject, says, “there are two kinds of oil of cinnamon procured in Ceylon, one of greater, the other of less specific gravity than water. In distillation they come over together. On what the difference depends I do not know, nor am I aware that the subject has yet been investigated.”
[474]. From experiments made with Veratria, it appears that its effects on the human system are analogous to those of the Colchicum itself. In chronic rheumatism comparative trials to a great extent were instituted by Dr. Bardsley, and with very similar results. The Veratria was generally administered in doses of from 1/4 gr. to ½ gr. three times a day. Ed.