According to Whitla, cinchonidine re sembles both quinine and cinchonine in action, but is less powerful than the first, being abont equal to the latter. Like cinchonine, it depresses the heart more than quinine.
Clinical experience has proved the cinchonidine salts to be reliable tonics and antiperiodics. They are said to be eliminated by the kidneys unchanged; also to produce less disagreeable symp toms, both gastric and cerebral, than quinine; but Rafferty, who administered more than three hundred ounces, affirms that it is apt to cause nausea and vomit ing. (Wood.) Quinelum.—This, as before men tioned, is known also as "cinchona febri fuge." It is an amorphous, dirty-white powder consisting of mixed alkaloids ob tained from the red-cinchona grove at the government plantations, Darjeeling, India; the alkaloids are in the same pro portion as found in the bark. The sul phate is a more presentable salt, and re sembles quinine sulphate. As the sub stance known as quinetum consists cbiefly of cinchonidine salts (from 50 to 70 per cent.), these latter probably will offer an efficient substitute. Neverthe less, it has almost replaced quinine in India, and is said to be more readily absorbed into the system than the crys talline alkaloids.
It is a well-known fact that the com bined alkaloids of the cinchona-bark are much more effective as a tonic than any one of them taken singly. They are to be preferred in combination also, in many instances, as an antiperiodic, particularly when the periodicity of the attack has been in some degree mitigated. It is for this reason that the East Indian Govern ment now provides its officials with "cin chona febrifuge,"—which is merely a combination of cinchona alkaloids—in preference to quinine. While cases are encountered where quinine is practically indispensable for a time, there are few which will not readily yield, and more satisfactorily, to a combination of cin chona alkaloids. Esencia de calasaya and cinchona febrifuge are practically iden tical, save that the former is a fluid medicament, the latter a powder. The esencia, moreover, is an ideal general tonic, and is particularly useful in atonic dyspepsia. In the alcohol habit it satis
factorily neutralizes the craving for spir its, and will be found of great service in treating this disease. Wingrave, Lond. (Med. Age, Sept. 25, '93).
Quinidine is believed to have the same action and medical properties as other cinchona salts, and to be equally as effi cacious as quinine without giving rise to the disagreeable nervous effects occa sionally observed when the latter is given in large doses. Efare says the dose should be double that of quinine, but it would seem preferable not to greatly surpass the dose of quinine.
Quinoidine, or Chinoidine.—There is little to say regarding this substance further than that it partakes of the na ture and characteristics of other cin chona preparations. As before remarked, it is a by-product, chiefly a mixture of such alkaloids as are not readily ex tracted, left after the major portion of the same have been crystallized out. It may be resolved into ordinary quinine, cinchonine, and quinidine alk-aloids, but is not generally held a profitable measure. Solutions in either boric or sulphuric acid are employed as cheap febrifuges, but their taste is very nauseous. Quinoi dine is neither as certain in composition or uniform in effects as quinetum.
Quinovic, kinovic, or chinovic acid is little employed, as it offers no advan tages over other cinchona derivatives: it poses rather as a chemical curiosity than as a medicament.
Cupreine is nearly allied to quinine, and generally on extraction from cuprea bark found conjoined with the latter: a combination that for a time obtained the title of homoquinine, it being supposed to be a specific alkaloidal entity. Both sulphate and muriate salts are manufact ured, but neither the two latter nor the alkaloid—though purported to be equally as efficacious therapeutically as the qui nine and its salts—have as yet secured a permanent position in the materia med ica.
For further consideration of the thera peutics of the cinchonas and their de rivatives, the reader is referred to QUI