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 a tree. Having freed the stem from adhering parasites and twining plants, he proceeds, by beating and cutting oblong pieces, to detach the stem bark as far as is within his reach. The tree is then felled, and the entire bark of stem and branches secured. The bark of the smaller branches, as it dries, curls up, forming “quills,” the thicker masses from the stems constituting the “flat” bark of commerce. The drying, packing and transport of the bark are all operations of a laborious description conducted under most disadvantageous conditions.

The enormous medicinal consumption of these barks, and the wasteful and reckless manner of procuring them in America long ago, caused serious and well-grounded apprehension that the native forests would quickly become exhausted. The attention of European communities was early directed to the necessity of securing steady and permanent supplies by introducing the more valuable species into localities likely to be favourable to their cultivation. The first actual attempt to rear plants was made in Algeria in 1849; but the effort was not successful. In 1854 the Dutch government seriously undertook the task of introducing the trees into the island of Java, and an expedition for that purpose was fitted out on an adequate scale. Several hundreds of young trees were obtained, of which a small proportion was successfully landed and planted in Java; and as the result of great attention the cultivation of cinchona plantations in that island became highly prosperous and promising. The desirability of introducing cinchonas into the East Indies was urged in a memorial addressed to the East India Company between 1838 and 1842 by Sir Robert Christison and backed by Dr Forbes Royle; but no active step was taken till 1852, when, again on the motion of Dr Royle, some efforts to obtain plants were made through consular agents. In the end the question was seriously taken up, and Sir Clements R. Markham was appointed to head an expedition to obtain young trees from South America and convey them to India. The transference of the plants was attended with considerable difficulty, but in 1861 under his superintendence a consignment of plants was planted in a favourable situation in the Nilgiri Hills. For several years subsequently additional supplies of plants of various species were obtained from different regions of South America, and some were also procured from the Dutch plantations in Java. Now the culture has spread over a wide area in southern India, in Ceylon, on the slopes of the Himalayas, and in British Burma, and has become widely spread through the tropics generally. The species grown are principally Cinchona officinalis, C. Calisaya, C. succirubra, C. pitayensis, and C. Pahudiana, some agreeing with certain soils and climates better than others, while the yield of alkaloids and the relative proportions of the different alkaloids differ in each species.

The official “bark” of the British Pharmacopoeia is that of Cinchona succirubra or red bark. It is imported in the form of quills or recurved pieces, with a rough brown outer surface and a deep red inner surface, forming a reddish brown odourless powder, which has a bitter, astringent taste. The British Pharmacopoeia directs that the bark, when used to make the various medicinal preparations, shall contain not less than 5 nor more than 6% of total alkaloids, of which at least one-half is to be constituted by quinine and cinchonidine. The preparations of this bark are four: a liquid extract, standardized to contain 5% of total alkaloids; an acid infusion; a tincture standardized to contain 1% of total alkaloids; and a compound tincture which must possess one-half the alkaloidal strength of the last. The only purpose for which these preparations of cinchona bark should be used is as tonics; and even when this is the desired action there are many reasons why the alkaloid should be preferred, even though the recent introduction of standardization removes one of the chief objections to their use.

The pharmacology of red bark, dependent as it is almost entirely upon the contained quinine, will not here be discussed (see ). But the composition of cinchona bark is a matter of importance and interest. The bark contains, in the first place, five alkaloids, of which all but quinine may here be dealt with. Quinidine, C20H24N2O2, is isomeric with quinine, from which it differs in crystallizing in prisms instead of needles, in being dextro- and not laevo-rotatory, and in being insoluble in ammonia except in much excess. Cinchonine has the formula C19H22N2O, quinine being methoxy cinchonine, i.e. C19H21(OCH3)N2O. It occurs in inodorous, bitter, colourless prisms; unlike the two alkaloids already named, does not yield a green colour with chlorine water and ammonia; is dextro-rotatory; not fluorescent, and practically insoluble in ammonia and in ether. A fourth alkaloid, cinchonidine, is isomeric with cinchonine, which yields it when boiled with amyl alcoholic potash, but is laevo-rotatory, slightly soluble in ether, and faintly fluorescent. When red bark is extracted with dilute hydrochloric acid, the product filtered, and excess of sodium hydrate added thereto, quinine and quinidine are precipitated: on concentrating the mother liquor, cinchonine falls down, and on further concentration with addition of still more alkali, cinchonidine is thrown out. Yellow bark, which is not official, yields 3% of quinine, and pale bark about 10% of total alkaloids, of which hardly any is quinine, cinchonine and quinidine being its chief constituents. The various forms of bark also yield a very small quantity of an unimportant alkaloid, conquinamine. In addition to the above, red bark contains quinic acid, C7H12O6, which is closely allied to benzoic acid and is excreted in the urine as hippuric acid. There also occurs chinovic acid, derived from a glucoside chinovin, which occurs as such in the bark. Besides a trace of volatile oil which gives the bark its characteristic odour, and cinchona red (the bark pigment), there occurs about 2% of cincho-tannic acid, closely allied to tannic acid and giving the bark its astringent property. Cinchona is never used, however, in order to obtain an astringent action.

The importance of recognizing the complex and inconstant composition of cinchona bark lies, as in so many other instances, in this—that the physician who employs it can have only a very imperfect knowledge of the drug he is using. The latest work on the action of these alkaloids has shown that cinchonine has a tendency to produce convulsions in certain patients, and that this action is a still more marked feature of cinchonidine and cinchonamine. Even small doses administered to epileptics increase the number of their attacks. They will probably be classified later among the convulsive poisons. The use of cinchona bark and its preparations, now that definite active principles can be readily obtained and precisely studied, is almost entirely to be deprecated. Quinidine is almost as powerful an antidote to malaria as quinine; cinchonidine has about two-thirds the power of quinine, and cinchonine less than one-half.

 CINCINNATI, a city and the county-seat of Hamilton county, Ohio, U.S.A., on the Ohio river, opposite the mouth of the Licking, about 100 m. S.W. of Columbus, about 305 m. by rail S.E. of Chicago, and about 760 m. (by rail) W.S.W. of New York. Through the city flows Mill Creek, which empties into the Ohio. Pop. (1890 ) 296,908; (1900) 325,902, of whom 197,896 were of foreign parentage (i.e. either their fathers or mothers or both were foreign-born), 57,961 were foreign-born, and 14,482 were negroes; (1910) 363,591. The German is by far the most important of the foreign elements. In addition to the large number of inhabitants of German descent, there were, in 1900, 107,152 of German parentage, and of the foreign-born 38,219 came from Germany.

Cincinnati is situated on the N. side of the river upon two terraces or plateaus—the first about 60 ft., the second from 100 to 150 ft., above low water—and upon hills which enclose these terraces on three sides in the form of an amphitheatre, rising to a height of about 400 ft. on the E. and of about 460 ft. on the W., and commanding magnificent views of the river, the valley, the numerous suburbs, and the more distant wooded hills. About half of the hill-enclosed plain lies S. of the river, and it is upon this southern half that Covington, Newport, Dayton, Ludlow and other Kentucky suburbs of Cincinnati are situated. Cincinnati has a river-frontage of about 14 m., extends back about 6 m. on the W. side in the valley of Mill Creek, and occupies a total area of about 44 sq. m. Since 1867 it has been connected with Covington by a wire suspension bridge designed by John A. Roebling, and rebuilt and enlarged in 1897. This bridge is 1057 ft. long between towers (or, including the approaches, 2252 ft. long), with a height of 101 ft. above low water, and has a double wagon road and two ways for pedestrians. By two bridges there is direct communication with Newport; by one, that of the Cincinnati Southern railway, with Ludlow; and by one (Chesapeake & Ohio; see vol. v., p. 109)