Cinchona bark contains two alkaloids, cinchonia and quina, to which its active properties are due; the former is best obtained from gray bark, the latter from yellow bark. In combination with these there exists an acid called kinic acid.
The imports of cinchona bark to this country are from 225,000 to 556,000 lbs. annually, and about 120,000 lbs. are retained for home consumption. It comes over in chests and serons, or ox-hides, varying from 90 to 200 lbs. We imported from France, in 1850, 489 cwt. of Peruvian bark, of the value of £6,840; and in 1851, 1,128 cwt., of the value of £15,787; also the following quantities of sulphate of quinine, on which there is a duty of 6d. and 3-10ths per ounce.
| oz. | £ | |
| 1848 | 3,856 | 5,898 |
| 1849 | 1,114 | 1,560 |
| 1850 | 8,976 | 12,566 |
| 1851 | 7,605 | 10,647 |
The following is the arrangement of these barks adopted by Pereira, who has gone very fully into the subject:—
A. True cinchonas, with a brown epidermis.
I. Pale barks 1. Crown or Loxa bark. C. Condaminea. 2. Gray or silver or Huanuco bark. C. micrantha. 3. Ash or Jaen bark. C. ovata. 4. Rusty or Huamalies bark. C. pubescens.
II. Yellow barks. 5. Royal, yellow or Calisaya bark. C. sp ?
III. Red barks. 6. Red bark. C. sp ?
B. True cinchonas, with a white epidermis.