Medicinal Properties of the Cinchona Barks. The therapeutic effects of the cinchona barks are doubtless due to the alkaloids they contain; but spite of their variability of composition in this respect, which has been shown to be very great, they are very extensively employed in medical practice in the forms of powder, decoction, tincture, and extract.
Dr de Vrij, the eminent quinologist, is of opinion that the therapeutic effects of bark are chiefly due in part to the alkaloids, and in part to the cincho-tannic acid they contain; and as red Indian bark is rich in both these constituents, he considers it the best suited for medical practice. See Quinetum.
Garrod says:—“Given in small doses, bark causes an increase of appetite, especially in weak patients, and at the same time improves the condition of the muscular system; hence the improvement of the blood and general health. It may, therefore, be well designated a tonic.
Its power in bracing up the system is also seen in the check given to the colliquative sweating occurring in extreme debility. The pulse is not quickened by the use even of large doses of quinine, although it is frequently made stronger, nor does bark itself, in the majority of cases, increase the heart’s action.
Bark also produces a peculiar influence upon the nervous system, which is exhibited in the extraordinary power it possesses of arresting the progress of certain diseases characterised by a periodical recurrence of their symptoms, as ague, the different forms of neuralgia, and certain inflammatory affections; how this effect is produced is at present unknown. Bark acts likewise as an astringent, and this property, combined with the tonic and antiperiodic powers, is often of much therapeutic value.”
For the method of estimating the alkaloids in cinchona bark, see Quinometry, Quinine, Quinidine, Quinoidine, Quinicone, Quinamine, Cinchonine; also the different pharmaceutical preparations of Cinchona bark.
CINCHONIDINE. Syn. Cinchonidia. C20H24N20. This cinchona alkaloid is isomeric with cinchonine. It occurs in large, shining striated, rhombic prisms, which are anhydrous. It dissolves in ·76 parts of ether and 20 of spirit of wine. The solutions are fluorescent, but do not answer to the chlorine and ammonia tests.
“The great powers and activity of this alkaloid have only of late been appreciated. As a protoplasm-poison, and probably in every other physiological action, it comes next to quinine and quinidine, and decidedly above cinchonine.”[248]
[248] Dr C. D. Phillips.
If it is chemically pure, cinchonidine belongs to the non-fluorescent alkaloids.