Barus Camphor, Borneo Camphor, Malayan Camphor, Dryobalanops Camphor—This, as already explained, is the substance to which the earliest notices of camphor refer. The tree which affords it is Dryobalanops aromatica Gärtn. (D. Camphora Colebrooke), of the order Dipterocarpeæ, one of the most majestic objects of the vegetable kingdom.[1909] The trunk is very tall, round, and straight, furnished near the base with huge buttresses; it rises 100 to 150 feet without a branch, then producing a dense crown of shining foliage, 50 to 70 feet in diameter, on which are scattered beautiful white flowers of delicious fragrance. The tree is indigenous to the Dutch Residencies on the north-west coast of Sumatra, between 0° and 3° N. lat., from Ayer Bangis to Barus and Singkel, and to the northern part of Borneo, and the small British island of Labuan.
The camphor is obtained from the trunk, in longitudinal fissures of which it is found in a solid crystalline state, and extracted by laboriously splitting the wood. It can only be got by the destruction of the entire tree;—in fact, many trees afford none, so that to avoid the toil of useless felling, it is now customary to try them by cutting a hole in the side of the trunk, but the observation so made is often fallacious. Spenser St. John, British Consul in Borneo, was told that trees in a state of decay often contain the finest camphor.[1910] The camphor when collected is carefully picked over, washed and cleaned, and then separated into three qualities, the best being formed of the largest and purest crystals, while the lowest is greyish and pulverulent.
Dryobalanops attaining more than 150 feet in height, the quantity of camphor which it yields must necessarily be greatly variable. The statements are from about 3 to 11 lb.
A good proportion of the small quantity produced is consumed in the funeral rites of the Batta princes, whose families are often ruined by the lavish expense of providing the camphor and buffaloes which the custom of their obsequies requires. The camphor which is exported is eagerly bought for the China market, but some is also sent to Japan, Laos, Cochin China, Cambodia, and Siam.
The quantity annually shipped from Borneo was reckoned by Motley in 1851 to be about 7 peculs (933 lbs.). The export from Sumatra was estimated by De Vriese at 10 to 15 quintals per annum.[1911] The quantity imported into Canton in 1872 was returned as 23⁷/₁₀ peculs (3,159 lb.), value 42,326 taels, equivalent to about 80s. per lb.[1912] In the Annual Statement of the Trade of Bombay for the year 1872-3, 2 cwt. of Malayan Camphor is stated to have been imported; it was valued at 9,141 Rs. (£914). In the “Indian tariff,” 1875, the duty is fixed per cwt. at 40 rupees for crude camphor, 65 rupees for refined camphor, and 80 rupees per pound for Baros camphor (“Bhemsaini camphor”). The price in Borneo in 1851 of camphor of fine quality was 30 dollars per catty, or about 95s. per lb.: consequently the drug never finds its way into European commerce.
Borneo Camphor, also termed by chemists Borneol or Camphyl Alcohol, is somewhat harder than common camphor, also a little heavier so that it sinks in water. It is less volatile, and does not crystallize on the interior of the bottle in which it is kept; and it requires for fusion a higher temperature, namely 198° C. It has a somewhat different odour, resembling that of common camphor with the addition of patchouli or ambergris. The composition of borneol is represented by the formula C₁₀H₁₇(OH). It may be converted by the action of nitric acid into common camphor, which it nearly resembles in most of its physical properties. Conversely, borneol may also be prepared from common camphor. By continued oxydation borneol yields camphoric acid.
Camphor Oil of Borneo—Besides camphor, the Dryobalanops furnishes another product, a liquid termed Camphor Oil, which must not be confounded with the camphor oil that drains out of crude laurel camphor. This Bornean or Sumatran Camphor Oil is obtained by tapping the trees, or in felling them ([see also p. 229]). In the latter way, Motley in cutting down a tree in Labuan in May, 1851, pierced a reservoir in the trunk from which about five gallons of camphor oil were obtained, though much could not be caught.[1913] The liquid was a volatile oil holding in solution a resin, which after a few days’ exposure to the air, was left in a syrupy state. This camphor oil, which is termed Borneene, is isomeric with oil of turpentine, C₁₀H₁₆, yet in the crude state holding in solution borneol and resin. By fractional distillation, it may be separated into two portions, the one more volatile than the other but not differing in composition.
Camphor Oil of Formosa, which has been already referred to as draining out of the crude camphor of Cinnamomum Camphora, is a brown liquid holding in solution an abundance of common camphor, which it speedily deposits in crystals when the temperature is slightly reduced. From Borneo Camphor Oil it may be distinguished by its odour of sassafras. We find no optical difference in the rotatory power of the oils; both are dextrogyre to the same extent, which is still the case if the camphor from the lauraceous camphor oil is separated by cooling. Borneo camphor oil, for a sample of which we are indebted to Prof. de Vriese, deposits no camphor even when kept at -15° C.
Ngai Camphor, Blumea Camphor—It has been known for many years that the Chinese are in the habit of using a third variety of camphor, having a pecuniary value intermediate between that of common camphor and of Borneo camphor. This substance is manufactured at Canton and in the island of Hainan, the plant from which it is obtained being Blumea balsamifera DC., a tall herbaceous Composita, of the tribe Inuloideæ, called in Chinese Ngai, abundant in Tropical Eastern Asia.
The drug has been supplied to us[1914] in two forms,—crude and pure,—the first being in crystalline grains of a dirty white, contaminated with vegetable remains; the second in colourless crystals as much as an inch in length. By sublimation the substance may be obtained in distinct, brilliant crystals, agreeing precisely with those of Borneo camphor, which they also resemble in odour and hardness, as well as in being a little heavier than water and not so volatile as common camphor.