The bark of C. flava, C. rubra, C. pallida.—South America.

Therapeutic Action.—Cinchona is tonic, antiperiodic, corroborant, stimulant, astringent and antiseptic. It is justly placed at the head of the tonics. The profession generally regard it as one of the most important remedies in the materia medica. Since its first introduction into the list of therapeutic agents, it has lost none of the high reputation which it at first enjoyed. On the contrary, the same popularity and the high confidence then resposed in it as a permanent tonic and anti-periodic are now freely awarded to it. The Peruvian bark—its alkaloid principles—the cinchonia or quinia, or their salts—is more frequently resorted to as corroborants in cases of debility, and more especially in diseases of an intermittent character as antiperiodics, than anyone or all others belonging to this class of remedial agents. The reason is obvious: no other article has so uniformly proved successful. It is the article upon which reliance has to a great extent been placed for two hundred years, during which time it has gained the confidence of physicians and secured a reputation in the treatment of diseases assuming periodicity which no other article now enjoys.

As a therapeutic agent, the cinchona is mostly employed in cases of debility, unattended with local irratation. "In such we find cinchona improves the appetite, promotes the digestive functions, and increases the strength of the pulse. The muscular system acquires more power, and the individual is capable of making greater exertion, both mental and bodily, than before; the tissues acquire more firmness to the touch, and lose their previous flabbiness; moreover, it has been asserted, and with great probability of truth, that the quality of the blood improves."

It often proves valuable in arresting profuse and debilitating night-sweats and other profuse discharges arising from debility, particularly in the convalescent stages of fever. It is also important in the advanced stages of continued fevers as a tonic, when there is great debility, provided no symptoms of celebral inflammation, or inflammation of the digestive or other vital organs be present.

The cinchona, or some of its preparations, is extensively used in the treatment of intermittent fever; and it rarely fails to arrest it, if judiciously administered. Some prescribe it not only during the intermission, but also throughout the whole period of excitement; and some premise with emetics and cathartics, while others usually omit all evacuants.

Although it may be employed in many cases during the pyrexial stage with advantage, yet we deem it most beneficial, as a general rule, during the period of apyrexia, especially if visceral congestion or local inflammation exist. If administered during the stage of excitement, the quantity necessary to moderate it is so great, that it proves irritating and oppressive to the stomach, and might increase the intensity of the fever, instead of diminishing it. The same objections are not obnoxious to the use of the sulphate of quinine, and consequently, if either is used, the salt is preferable.

The American Eclectic Materia Medica and Therapeutics, 1898, was written by John M. Scudder, M.D.