II.—Camphor.
§ 153. A great many essential oils deposit, after exposure to air, camphors produced by oxidation of their terpenes. Ordinary camphor is imported in the rough state from China and Japan, and is prepared by distilling with water the wood of Camphora officinarum; it is resublimed in England. The formula of camphor is C10H10O; it has a density of ·986 to ·996; melts at 175°, and boils at 205°. It is readily sublimed, especially in a vacuum, and is indeed so volatile at all temperatures, that a lump of camphor exposed to the air wastes away. It is somewhat insoluble in water (about 1 part in 1000), but this is enough to impart a distinct taste to the water; it is insoluble in chloroform, ether, acetone, acetic acid, carbon disulphide, and oils. It has a fragrant odour and a burning taste. A 10 per cent. solution in alcohol turns a ray of polarised light to the right +42·8°. By distillation with zinc chloride, cymene and other products are produced. By prolonged treatment with nitric acid, camphor is oxidised to camphoric acid (C10H16O4). Camphor unites with bromine to form a crystalline, unstable dibromide, which splits up on distillation into hydrobromic acid and monobrom-camphor (C10H15BrO). The latter is used in medicine; it crystallises in prisms fusible at 76°, and is readily soluble in alcohol.
§ 154. Pharmaceutical Preparations.—The preparations officinal in the British Pharmacopœia are camphor water—water saturated with camphor, containing about one part per thousand.
Camphor Liniment.—A solution of camphor in olive oil, strength 25 per cent.
Compound Camphor Liniment.—Composed of camphor, oil of lavender, strong solution of ammonia and alcohol; strength in camphor about 11 per cent.
Spirit of Camphor.—A solution of camphor in spirit; strength, 10 per cent.
Camphor is also a constituent of the compound tincture of camphor; but in this case it may be considered only a flavouring agent. There is a homœopathic solution of camphor in spirit (Rubini’s Essence of Camphor). The solution is made by saturating alcohol with camphor; it is, therefore, very strong—about half the bulk consisting of camphor. Camphor is used in veterinary medicine, both externally and internally.
§ 155. Symptoms.—Camphor acts energetically on the brain and nervous system, especially if it is given in strong alcoholic solution, and thus placed under conditions favouring absorption. Some years ago, Dr. G. Johnson[145] published a series of cases arising from the injudicious use of “homœopathic solution of camphor,” from 7 to 40 drops of Rubini’s homœopathic camphor taken for colds, sore throat, &c., having produced coma, foaming at the mouth, convulsions, and partial paralysis. All the patients recovered, but their condition was for a little time alarming.
[145] Brit. Med. Journ., Feb. 27, 1878, p. 272; see also ibid., Feb. 1875.
The cases of fatal poisoning by camphor are very rare. A woman, aged 46, pregnant four months, took 12 grms. (about 184 grains) in a glass of brandy for the purpose of procuring abortion. In a very short time the symptoms commenced; she had intolerable headache, the face was flushed, and there was a sensation of burning in the stomach. In eight hours after taking the dose, she had strangury and vomiting, and the pain in the epigastrium was intense. These symptoms continued with more or less severity until the third day, when she became much worse. Her face was pale and livid, the eyes hollow, the skin cold and insensible, pulse weak and thready, breathing laboured. There were violent cramps in the stomach and retention of urine for twenty-four hours, and then coma. The patient lingered on yet another three days, aborted, and died.[146]
[146] Journ. de Chim. Méd., May 1860.
Dr. Schaaf[147] has recorded three cases of poisoning—one of which was fatal. A woman gave about half a teaspoonful of a camphor solution to each of her three children, the ages being respectively five and three years and fifteen months. The symptoms noted were pallor of the face, a burning pain in the throat, thirst, vomiting, purging, convulsions, and afterwards coma. The youngest child died in seven hours; the others recovered. The smallest dose known to have produced violent symptoms in an adult is 1·3 grm. (20 grains); the largest dose known to have been recovered from is 10·4 grms. (160 grains).[148]
[147] Journ. de Chim. Méd., 1850, p. 507.
[148] Taylor on Poisons, 3rd ed., 661.
§ 156. Post-mortem Appearances.—The bodies of animals or persons dying from poisoning by camphor, smell strongly of the substance. The mucous membrane of the stomach has been found inflamed, but there seem to be no characteristic lesions.
§ 157. Separation of Camphor from the Contents of the Stomach.—The identification of camphor would probably in no case present any difficulty. It may be readily dissolved out from organic fluids by chloroform. If dissolved in fixed oils, enough for the purposes of identification may be obtained by simple distillation. It is precipitated from its alcoholic solution by the addition of water.