The Indian Government, acting on the recommendation of Mr. Howard, has officially advised (Dec. 16, 1873) the more free use India of cinchona alkaloids other than quinine, and especially of sulphate of cinchonidine, which is procurable in abundance from Red Bark.[1371] Quinidine on the other hand, which has proved the most valuable of all, is only obtainable from a few barks and in very limited amount.
Dr. de Vry since 1876 advocates the use of what he calls Quinetum. This preparation is obtained by exhausting the barks with slightly acidulated water, and precipitating the whole amount of alkaloids by caustic soda. In India the remedy is known as “the Febrifuge.”[1372]
Adulteration—There is not now any frequent importation of spurious cinchona barks, but the substitution of bad varieties for good is sufficiently common. To discriminate these in a positive manner by ascertaining the percentage of quinine, which is the chief criterion of value, recourse must be had to chemical analysis, a method of performing which has been described. Entirely worthless barks may be easily recognized by means of Grahe’s test ([p. 363]). Modern Works relating to Cinchona.
The following enumeration has been drawn up for the sake of those desiring more ample information than is contained in the foregoing pages, but it has no pretension to be a complete list of all publications that have lately appeared on the subject.
Berg (Otto), Chinarinden der pharmakognostischen Sammlung zu Berlin. Berlin, 1865, 4°. 48 pages and 10 plates showing the microscopic structure of barks.
Bergen (Heinrich von), Monographie der China. Hamburg, 1826, 4°. 348 pages and 7 coloured plates representing the following barks:—China rubra, Huanuco, Calisaya, flava, Huamalies, Loxa, Jaen. An exhaustive work for its period in every direction.
Blue books—East India (Chinchona Plant). Folio.
a. Copy of Correspondence relating to the introduction of the Chinchona Plant into India, and to proceedings connected with its cultivation from March 1852 to March 1863. Ordered by the House of Commons to be printed, 20 March 1863. 272 pages.
Contains Correspondence of Royle, Markham, Spruce, Pritchett, Cross, McIvor, Andersen and others, illustrated by 5 maps.
b. Copy of further Correspondence relating to the introduction of the Chinchona Plant into India, and to proceedings connected with its cultivation, from April 1863 to April 1866. Ordered by the House of Commons to be printed, 18 June 1866. 379 pages.