CAMPHOR. (FR., Camphre ; GER., KaMpher.) The name " camphor" ie technically applied to a great number and variety of gum-resins, all of Na getable origin, and possessing more or less similar general characteristics, coupled with rninor distinctive peculiarities. Three kinds only are objects of commerce ; they are derived from (1) LUUMS camphora (Cinnamomum camphora, Camphora officinarum), the well-known camphor laurel of China and Japan ; (2) Dryobalanops camphora (or aromatica), a gigantic tree inhabiting the Malay Archipelago ; and (3) Blumea balsam' f era. The products are known respectively as Common camphor, Borneo camphor, and Blumea camphor. Each of these will be considered under a separate head; and, at the end of the article, will be added short descriptions of the less-known " camphors" of pharmacy.
Common or Laurel Camphor.—C. H„ O. This is a colourless, transparent body, of tough, waxy, structure, linving a specific gravity about equal to that.of water, melting at 175° (347° F.), and boiling at 204° (400° F.). It volatilizes readily at ordinary temperatures, giving off the peculiar pungent aromatic odour which characterizes it. Recent researches prove it to be a phenol. It is very slightly soluble in water, to which it communicates its warm camphor taste ; but in alcohol, ether, fixed and volatile oils, naphtha, aniline, &c., it dissolves with facility. On subjection to the action of oxidizing agents, it is transformed into camphoric acid, 8,nd, if the oxidation be continued, camphretic acid, 0,0 H,4 0,, will result.
The camphor laurel is a gigantic evergreen, bearing considerable resemblance to the common laurel, except in the matter of size, attaining, as it sometimes does, to a height of 50 ft. and a girth of 20 ft., with branches 8 or 9 ft. in circumference. The leaves are shining, and of a bright green colour, emitting a camphoraceous odour when bruised. The wood is white and fragrant, and is much used by the Chinese in carpentry, as it is proof against the attacks of insects. The chief habitat of the shrub is the island of Formosa, where it reaches the greatest size, and where most of the camphor of western commerce is produced. It alrso flourishes in China, the Chum Archi pelago, and Japan ; the last-named country exporting considerable quantities of the drug. The shrub has now become naturalized in most of the tropical aud warmer temperate countries of tbe world, as in Java, Brazil, Jamaica, and the West Indies generally, Cape of Good Hope, Mauritius, 1VIadeira, and the Mediterranean region ; and it has been proposed to introduce it into South Georgia aud Florida. It forms a large and handsome tree in sheltered spots in Italy, as far north as the Lago Maggiore ; it is commonly found in all the nurseries around Paris, and is not unknown in this country. The drug obtained from this laurel is prepared exclusively, or nearly so, for the markets of the West, and constitutes the only camphor of European and American e,ommere,e. As the native processes of collecting and preparing the substance vary in the different
countries where the shrub is indigenous, it may be best treated geographically.
1. Formosa.—In the district of this island included under Chinese territory, the camphor laurel is not found ; it is confined to the country of the aborigines, and its immediate borders. This circumstance is owing to the fact that the extraction of the camphor entails the destruction of the shrub ; as this destruction has never been compensated by replanting, the forest has been gradually cleared away, the aborigines receding and the Chinese encroaching as the work of destruction has progressed. In consequence of the disturbed relations between the two races, thus induced on the border lands, the risk attending the camphor trade is very great, the distillers requiring to be always on their guard against attack ; nevertheless, the industry maintains its ground. The method of preparing Formosan camphor is as fellows :—The shrubs, as required, are selected for the abundance of their sap, many being too dry to repay the cost and labour of treatment. The best part of the wood is secured for timber ; while the branches and refuse are taken, while freshly cut, 8,nd chopped up into little pieces for distillation. The stills, built up in sheds and moved as the Chinese advance into the interior, are of very rude construction ; ever eight or ten hearth fires, is placed long wooden trough, often a hollowed tree, coated with clay and half filled with water. Boards pierced with holes are fitted on the trough, and above these are placed jars containing the chips; the latter are surmounted by inverted earthenware pots, and the joints are made airtight by means of hemp packing. When the fires are kindled, the generated steam passes up through the pierced beards and, saturating the chips, causes the sublimated camphor to settle in crystals on the inside of the pots, from which it is scraped off, and afterwards passed through second process of distillation to remove some of the impurities. At the bottom of a copper still, is placed a bed of dry powdered earth from an old wall (selected, doubtless, for the sake of the lime it contains), and on this a layer of crude camphor ; this is again covered with earth, and so on alternately till the vessel is full, the series terminating with a stratum of earth, and being finally covered with green mint. A second vessel, usually formed of straw smeared with clay en the outside, is inserted over the still and luted on. The apparatus is placed ever a regulated fire, and the contents are heated for a considerable time. After cooling, the camphor is found to have sublimed, and attached itself to the upper vessel.