“From the above statement respecting the solubility of quinidine in ether, it appears that the 10 gr. of the salt examined may contain 1 gr. of quinidine, and still a complete solution with ether and ammonia may follow; but in this case the quinidine will shortly begin to crystallise in a layer of ether. The least trace of quinidine may be yet more definitely detected by employing, instead of the ordinary ether, some ether previously saturated with quinidine, by which means all of the quinidine contained in the quinine examined must remain undissolved. It is particularly requisite, in performing this last experiment, to observe, (immediately) after the shaking, whether all has dissolved; for, owing to the great tendency of quinidine to crystallisation, it may become again separated in a crystalline form, and be a source of error.”
“If more than 1-10th of quinidine or (any) cinchonine be present, there will be found an insoluble precipitate at the limits of the two layers of fluid. If this be quinidine, it will be dissolved on the addition of proportionately more ether, while cinchonine will remain unaffected.”
Note. To Dr Ure’s test Dr de Vrij prefers, for several reasons, Dr Kerner’s test, ‘Zeitschrift
für Analytische Chemie,’ von Fresenius, 1st Jahrg, 1862; ‘Ueber Die Prufung des Käuflichen Schwefelsauren Chinins auf fremde Alkaloides,’ von Dr G. Keraer.
QUINOVIC ACID. C28H33O4. This is insoluble in water, also in chloroform, and difficultly soluble in alcohol. It can be obtained from the boiling alcoholic solution, by cooling, in small crystals. In the leaves, bark, and wood of the cinchona tree this acid is contained, together with quinovin, and it is this mixture which has been recently applied in therapeutics, as a powerful tonic in cases of dysentery, &c. The mixture can easily be obtained from the leaves, bark, or wood of cinchona, and even from bark which has been exhausted by ebullition with water or diluted acids, by cold maceration with weak milk of lime, by which it is dissolved, as it combines easily with bases. It is only the quinovate of lime which has till now been used in medicine.—Dose, 2 to 8 gr. every two hours.
QUINOVIN. C30H48O8. Syn. Cinchovin, Quinovia.
QUINOVIN. A very bitter amorphous glucoside contained in the genus Cinchona, Nauslea, and probably in many other allied genera. It is insoluble in water, very soluble in rectified spirit and in chloroform, with which last liquid it forms, in concentrated solutions, a jelly. If a current of hydrochloric gas is passed into its alcoholic solution the liquid becomes hot and the quinovin is split up into a peculiar kind of sugar.
QUIN′QUINA. Dr de Vrij states that the substance known under this name is a mixture of hydrochlorate of cinchonidine and of cinchonine. See Cinchona.
QUIN′SY. See Throat affections.
QUINTES′SENCE. Syn. Quinta essentia, L. A term invented by the alchemists to