Quinia, or any salt of this alkaloid, produces all the effects of yellow cinchona bark, except that it is not astringent; it may be given in all cases where bark is indicated - generally with some advantage over bark itself, on account of the smallness of the dose required, and its little liability to disturb the stomach; the only exceptions Would be, cases of great debility of the system, with excessive weakness of the circulation and increased secretions; in these the pharmaceutic preparations of cinchona barks appear at times to be preferable.

Cinchonia is generally supposed to have a similar action to quinia, differing only in degree, being regarded as much weaker: that it possesses antiperiodic powers is undoubted, whether equal to quinia, or not, requires still to be determined. The author has had abundant evidence to prove that peculiar effects often result from cinchonia salts, which are not produced by the same amount of the corresponding salts of quinia.

Quinidine appears to act in the same way as quinia, but whether equal in power has not yet been determined.

Cinchonidine probably acts in the same manner as cinchonine, but a further investigation of its powers is required.