Page:The American Cyclopædia (1879) Volume IV.djvu/598

 586 CINCHONA trunk, and of all most impure in that of the roots. Quinia, the most important of the al- kaloids, has the formula CioIIiuNsH^ is crystal- lizable, slightly soluble in hot and cold water, and very soluble in alcohol, ether, and chloro- form. It forms crystallizable salts with several acids. It may be precipitated as a hydrate from a solution of a salt by an alkali or alkaline earth. Ammonia in excess redissolves the pre- cipitate. Sulphate of quinia, or more proper- ly the disulphate, is the medicine commonly known as quinine. It consists of one equiva- lent of sulphuric acid, 40, two of quinine, 324, and 8 of water, 72=436. It is in fine, white, silky crystals, which on exposure to the air ef- floresce and lose their form together with their water of crystallization. It dissolves in 30 parts of boiling water, but separates on cooling. In ether it is slightly soluble. Alcohol when cold takes up one part in 60, and the diluted acids, tartaric and oxalic, dissolve it freely. In water acidulated with sulphuric or other acid it read- ily dissolves, and this property is taken advan- tage of in administering the medicine in a liquid form. The manufacture of quinine is exten- sively carried on in Paris, in Stratford, Eng- land, and in Frankfort, from which place Rus- sia, Prussia, and Austria are chiefly supplied with this medicine. In Philadelphia the busi- ness of extracting it from the bark is conduct- ed in chemical establishments also upon a very large scale. The quinine in the process of its extraction is commonly converted into the sulphate, which is the salt chiefly employed in medicine, and of which from 2 '5 to 3 per cent, is usually obtained from the yellow bark. The processes employed vary somewhat in differ- ent countries. From a strong decoction of the bark in water, acidulated with hydrochloric acid and filtered, the quinine may be set free from its combination with kinic acid and pre- cipitated by addition of lime water ; some lime combined with coloring matter falls with it. The precipitates are well washed with water, and the residuum is pressed, dried, and pulver- ized. It is then repeatedly treated with alco- hol, which dissolves the quinine and leaves most of the impurities. These being separated, the solution is concentrated by evaporation to a brown viscid mass, which is impure quinia; or the tincture in the distilling vessel may be neutralized with sulphuric acid, and the alcohol being then distilled' off, an impure sulphate is obtained which crysvallizes on cooling. This is expressed, and then dissolved in boiling water to which purified animal charcoal has been added. It is filtered while hot, and then al- lowjsd to cool and crystallize. The purification is completed by again dissolving and crystalliz- ing. Sulphate of cinchonia is commonly pres- ent, but being more soluble does not crystallize so readily as the sulphate of quinia, and re- mains in the mother liquor. This also contains what Liebig regards as an amorphous variety of quinine, which is analogous in itt properties to uncrystallizable sugar ; it is known as qui- noidine, and possesses the same medical prop- erties as the sulphate. It probably consists chiefly of quinicia and cinchonicia. The solu- ble salts of quinia form precipitates with tan- nic acid, with the soluble salts of lead and baryta, with a solution of iodine in iodide of potassium, and with the iodohydrargyrate of potassa. It is distinguished from the other alkaloids, with the exception of quinidia, by the production of an emerald green color when the solution is treated first with the solu- tion of chlorine and then with ammonia, and which changes to a white or violet upon satu- ration with a dilute acid. Some of the salts of quinia, especially the sulphate, possess the re- markable property, called fluorescence, of ren- dering visible as a pale blue the ultra-violet rays of the spectrum, and an exceedingly small quantity may be detected by examining even in ordinary light a long tube filled with its colorless solution. The test is much more delicate when the electric light is used. Hy- drochloric acid or chloride of sodium renders the reaction much less distinct, or in ordinary light imperceptible. The sulphate of iodo- quinia, as well as the corresponding salts of the other alkaloids, possesses the property of polar- izing light, in which it is equal if not superior to tourmaline. Quinidia is isomeric with quinia, and resembles it in many of its chemical reac- tions. It is distinguished from quinia by its greater facility of crystallization, its less solu- bility in ether, and its influence on polarized light. It forms a precipitate with iodide of potassium, a property possessed by no other cinchona alkaloid. Cinchonia has the formula C4oII4N a Oa, is crystallizable, only very slightly soluble in water, cold alcohol, and ether. It forms salts with acids. It is obtained chiefly from the pale barks. Cinchonidia is isomeric with cinchonia, but differs from it in being more soluble in ether and also in its influence on polarized light. Commercial quinidia gen- erally consists of quinidia proper with a much larger proportion of cinchonidia. Quinicia and cinchonicia are isomeric with quinia and cin- chonia respectively, but are uncrystallizable. The different varieties of bark contain these alkaloids in varying proportions, the yellow yielding chiefly quinia, the pale a larger pro- portion of cinchonia with but little quinia, and the red a considerable proportion of each. Ac- cording to the " United States Pharmacopoeia," cinchona bark should contain at least 2 per cent, of the proper cinchona alkaloids which yield crystallizable salts. The cinchona alka- loids, and especially the sulphate or disulphate of quinia, are largely used in medicine. Their most striking and earliest discovered property is that of preventing an expected access of in- termittent fever. For this purpose quinia should be administered in large doses. Two to 15 grains may be given at a time some hours before the expected chill, but not more than 30 or 40 grains should be given during the 12 hours preceding one. If administered sub-