Page:Encyclopædia Britannica, Ninth Edition, v. 20.djvu/203

QUININE 185 chloride of ammonium, and most acids. It is not soluble in fixed oils or in ether, although the pure alkaloid is soluble in both. It becomes phosphorescent on trituration. When prescribed it is generally rendered more soluble in water by the addition of dilute sulphuric acid or of citric acid, one drop of the former or fths of a grain of the latter being used for each grain of the sulphate of quinine. When a solution of quinine is exposed to sunlight it assumes a yellowish or brown colour due to the formation of " quinirctin," a body which is isomeric with quinine but has not an alkaline reaction, is not precipitated by tannin, and has an aromatic as well as a bitter taste. Quinine is precipitated from its solution by alkalies and their carbonates. It is very soluble in solution of ammonia, and also slightly soluble in lime water. The acid solution of sulphate of quinine is fluorescent, especially when dilute ; it is levogyrate ; and when a solution of chlorine is first added and then ammonia an emerald green colour, due to the formation of thalleoquin, is developed. This test answers with a solution contain- ing only 1 part of quinine in 5000, or in a solution containing not more than ^TJ-^^ part if bromine be used instead of chlorine. The fluorescence is visible in an acid solution containing one part in 200,000 of water. Quinine forms with sulphuric acid and iodine a com- pound known as herapathite, 4C 20 H 24 N 2 O 2 .3SO 4 H 2 .6I + 3H O, which possesses optical properties similar to those of tourmaline; it is soluble in 1000 parts of boiling water; and its sparing solubility in cold alcohol has been utilized for estimating quinine quantitatively. The other alkaloids are distinguished from quinine thus: quinidine resembles quinine, but is dextrogyrate, and the iodide is very in- soluble in water ; the solution of cinchonidine, which is levogyrate, does not give the thalleoquin test, nor fluor- escence ; cinchonine resembles cinchonidine in these respects, but is dextrogyrate. Commercial sulphate of quinine frequently contains from 1 to 10 per cent, of the sulphate of cinchonidine owing to the use of barks containing it. The sulphate of cinchonidine is more soluble than that of quinine ; and, when 1 part of quinine sulphate suspected to contain it is nearly dissolved in 24 parts of boiling water, the sulphate > of quinine crystallizes out on cooling, and the cinchonidine j is found in the clear mother liquor, from which it can be precipitated by a solution of tartrate of potassium and sodium. Samples of quinine in which cinchonidine is present usually contain, according to Hesse, a smaller per- centage of water than the pure sulphate, the cinchonidine salt exercising a reducing influence on the quinine salt in this respect. Traces of quinidine are also sometimes, though rarely, found in commercial quinine, but, since quinidine is even more valuable as a medicine than quinine, its presence does not detract in a medicinal point of view from the value of the latter. Owing to its voluminous character, as much as 18 per cent, of water may remain present in apparently dry samples of sulphate of quinine. If it loses more than 14'6 per cent, of water when dried at 100 C. it contains an excessive amount of moisture. Owing to its variability in this respect the hydrochlorate of quinine has been recommended as a more constant salt ; it also possesses advantages from a therapeutical point of view. Sulphate of quinine manufactured from cuprea bark (Remijia pedunculatcC) is liable to contain from '10 to '90 per cent, of sulphate of homoquinine, which almost coincides in solubility with sulphate of quinine. Homo- quinine has been shown by Paul and Cownley to be decomposed on treatment with caustic soda into quinine and a new alkaloid, cupreine, in the proportion of 2 to 3. They have also shown that cupreine is soluble in a solu- tion of caustic soda (differing in this respect from quinine), and that therefore it is easy to prepare sulphate of quinine perfectly free from either homoquinine or cupreine. So far as the medicinal properties of cupreine and homo- quinine are at present known they appear to be of no practical importance. 1 In consequence of the high price of the alkaloid an attempt was made a few years since by the Government of India to manufacture from cinchona bark a cheap febrifuge which should represent the alkaloids contained in the bark and form a substitute for quinine. This enterprise met with such success that in 1884 as much as 8714 Bb of the febrifuge were prepared; and during the previous year 9144 Bb were distributed, of which 4880 ft were supplied to the Government institutions at a cost of little more than a rupee per ounce. This mixture is known as cinchona febrifuge, and is prepared chiefly from C. succirubra, which succeeds better in India than the other species in cultivation, and grows at a lower elevation, being consequently procurable in large quantities at a comparatively low price. A mixture of the cinchona alkaloids, consisting principally of cinchoni- dine sulphate, with smaller quantities of the sulphates of- quinine and cinchonine, is sold under the name of " quine- tum" at a cheaper rate than quinine. In 1870 the Indian Government purchased no less than 81,600 ounces of sulphate of quinine, besides 8832 ounces of the sulphates of cinchonine, cinchonidine, and quinidine ; but at the present date it is able to meet the require- ments of its establishments almost entirely by the cinchona febrifuge prepared at the Government plantations in India. Although quinine is manufactured in the United States, a large quantity has been imported from Europe since the high duty levied on its manufacture has been removed. There is considerable difficulty in obtaining trustworthy statistics as to the extent of the manufacture of quinine. The largest sale that has taken place in America appears to have been in 1883, when 1|- tons were put up to auction, and in the same year 16,000 ounces were sold in London and a similar quantity at Berlin. Physiological Action. Quinine arrests the movements of the white corpuscles of the blood, rendering them round and darkly granulate, and, by preventing them from making their exit from the blood-vessels, diminishes or arrests the formation of pus in inflammation and causes contrac- tion of the spleen when that organ is enlarged. It acts upon the cerebro-spinal nervous system, giving rise to headache and a sense of tension in the brain ; these symptoms may be removed by the addition of hydrobromic acid or prevented by the use of the hydrobromide of quinine. It acts through the sympathetic nervous system on the heart, and is thus capable of restraining all the animal processes which develop heat, organic changes, or muscular action. It is antagonistic to atropine in its physiological action. The use of quinine in medicine dates from its discovery in 1820. Its chief value is as an antiperiodic, especially in intermittent fevers, but also in other diseases when they assume a periodic character, such as neuralgia, asthma, hooping cough, <tc. In blood poisoning, whether arising from natural or traumatic causes, it has been found of great utility. Its curative powers in sunstroke have been repeatedly proved in the East Indies, and a dose of quinine will often cut short an attack of catarrh if taken in the early stage. In malarial districts persons have 1 Pharm. Jour, and Trans., [3], vol. xii. p. 497, and vol. xv. p. 729. XX. 24