Nat. Ord.— Lauraceae. Sex. Syst.— Enneandria Monogynia.
Camphor is a peculiar concrete substance derived from Laurus Camphora and purified by sublimation. It is chiefly brought to this country from Canton, in the crude state, and undergoes purification before it can be used for medicinal purposes.
Description. — Laurus Camphora is an evergreen tree of considerable size, with a trunk straight below, but divided above into many drooping, smooth branches, covered with a greenish bark. The leaves are alternate, on long footstalks, ovate-lanceolate, somewhat coriaceous, entire, smooth, bright-green and shining above, paler beneath, triple-nerved, with a depressed gland opening by a pore at the axils of the principal lateral veins beneath, and two or three inches in length. Petioles an inch to an inch and a half long, slender, smooth. Panicles axillary and terminal, corymbose, naked. Leaf-buds scaly. Flowers small, white, smooth externally, pedicelled, and in clusters.
History. — The Camphor tree is a native of Japan, China, the East Indies, etc. It is an aromatic tree, all parts of it yielding the odor of camphor. Camphor is obtained in Japan by cutting the wood, roots, etc., of the tree in small pieces, boiling them in water, in large iron vessels, over which are placed earthen capitals, containing rice-straw cones. The heat sublimes the camphor, which rises into the capital and condenses upon the straw. In China, the process is somewhat different; the pieces of the tree are boiled in water until the camphor concretes upon the stick used in stirring ; the liquor is then strained and allowed to cool, when the camphor hardens. This is then placed in alternate layers with finely powdered dry earth, in a copper basin, on which another is inverted, and heat being applied, the camphor sublimes and adheres to the upper vessel. In this state it is impure, and of a dirty-grayish color, being known as Crude Camphor; it is re-sublimed for pharmaceutical and other uses.
Camphor has a crystalline texture ; white, translucent and shining, brittle, but somewhat elastic, of a powerful, penetrating, diffusible odor, and of a pungent, bitter, cooling taste. It cannot be pulverized alone, but is easily so by the aid of a few drops of alcohol. It slowly evaporates when exposed to the air, and is soluble in alcohol, ether, fixed and volatile oils, and acetic, nitric, and sulphuric acids. Nitric acid converts it into camphoric acid and oil of camphor; sulphuric, into artificial tannin and charcoal. Resins and fats, when heated with it, unite in all proportions. By the application of polarized light, the smallest portion of natural camphor may be distinguished from the artificial camphor (hydrochlorate of camphene). If small fragments of each be placed separately on glass slides, and a drop of alcohol added to each, they dissolve and speedily re-crystallize. If the crystallization of the natural camphor is watched by means of the microscope and polarized light, a most beautiful display of colored crystals is seen, while with the artificial camphor nothing of the kind is witnessed. Camphor is lighter than water, and keeps up a constant rotatory motion when small fragments are placed on that fluid. It volatilizes at ordinary temperatures, melts at 288°, and boils at 400°. It is considered to be an oxide of camphogene, or camphene, which is composed of ten equivalents of carbon 60, and eight of hydrogen 8=68. With one equivalent of oxygen, (C10 H8 0) camphene forms camphor; with four, hydrated camphoric acid; and with half an equivalent of hydrochloric acid, artificial camphor.
When camphor is triturated with dragon's blood, guaiacum, galbanum, or assafoetida, the mixture preserves the pilular consistence indefinitely. With benzoin, tolu, mastic, and ammoniac, the mixture becomes soft, by exposure to the air. With olibanum, gamboge, euphorbium, amber, and myrrh, the mixture remains pulverulent, though grumous. Assafoetida, galbanum, sagapenum, tolu, dragon's blood, olibanum, mastic, benzoin, tacamahac, guaiacum, and ammoniac, destroy to a greater or less extent the odor of camphor.
Properties and Uses. — In large doses camphor is a narcotic and irritant ; in small ones, sedative, anodyne, antispasmodic, diaphoretic, and anthelmintic. It appears to influence chiefly the cerebral and nervous systems, through the agency of which it affects the circulation. Mucous membranes with which it comes in contact are irritated directly, and acceleration of the circulation may ensue as a secondary effect. It is used to allay nervous excitement, subdue pain, arrest spasm, and sometimes to induce sleep. In the delirium, watchfulness, tremors, and starting of the tendons in typhoid conditions, it is of much utility as a nervo-stimulant. In inflammatory affections, as remittent and intermittent fevers, acute rheumatism, etc., it acts beneficially as a diaphoretic and sedative ; and is also valuable in gout, neuralgia, dysmenorrhea, after-pains, puerperal convulsions, and painful diseases of the urinary organs, acting as a sedative, anodyne, and antispasmodic. It is often advantageously combined with opium in chordee, and hysteric nymphomania, and all irritations of the sexual organs. By some physicians it is said to act as an aphrodisiac, exciting the urinary and genital organs causing a burning sensation along the urethra, and voluptuous dreams , by others again, it is used as an antaphrodisiac, and to allay urinary and genital irritations. It is said to be an antidote to poisoning by strychnia. An oleaginous injection of camphor in the early stage of gonorrhea, often allays urethral irritation; also, the tenesmus from ascarides and dysentery, when injected into the rectum. It enters into many embrocations and liniments for rheumatic, neuralgic, and deep-seated pains, cynanche tonsillaris, contusions from blows, sprains, chilblains, chronic cutaneous diseases, and as a stimulant for indolent and gangrenous ulcers. The vapor of camphor, inhaled into the lungs has been found beneficial in asthma and spasmodic cough ; and the powder may be used as a snuff for the relief of nervous headache, and catarrh in its commencing stage. The best form of using this agent is the aqua-camphorae. The administration of opium will best counteract the injurious effects of an overdose of camphor. Dose of the powder, one to ten grains. When given in the solid form, it is capable of producing ulceration of the gastric mucous membrane.
Off. Prep. — Aqua Camphorae ; Emplastrum Plumbi Compositum; Emplastrum Resinae Compositum ; Emplastrum Calefaciens ; Linimentum Camphori Compositum ; Linimentum Saponis Camphoratum ; Linimentum Olei Compositum ; Linimentum Capsici Compositum ; Linimentum Opii ; Mistura Camphorae Composita ; Mistura Copaibae Composita ; Pulvis Ipecacuanhae et Opii ; Pilulae Camphorae Compositae ; Tinctura Camphorae ; Tinctura Camphorae Composita ; Tinctura Serpentariae Composita; Tinctura Opii Acetata; Unguentum Plumbi Compositum.