Camphors - Poisonous Drugs

Camphors are volatile substances, which form crystals at ordinary temperatures. They bear much the same relation to volatile oils that fats do to fixed oils, that is to say they are volatile oils of comparatively high melting-point. By camphor is most commonly understood the gum-like drug obtained by distillation from the wood of the camphor-tree (Fig. 169). This drug is conveniently distinguished as laurel camphor or laurinol. Its chemical formula is C₁₀H₁₆O. The volatile nature of laurinol is prettily exhibited by gently heating a little piece in the bottom of a glass tube held obliquely so that the vapor as it rises will come in contact with the cool glass at the upper end. Here will be formed snowlike crystals as the vapor condenses. Similar crystals may be noticed at the upper part of bottles in which camphor has been kept for some time. If small bits of laurel camphor be placed upon the surface of pure water contained in a perfectly clean vessel the fragments will float and display curious animal-like movements due to the liberation of camphor vapor. The movement is checked by the presence of even a slight trace of oil. Laurel camphor has many important uses which need not here be mentioned. It should be remembered, however, that taken internally it is a powerful poison, ten grains (about 0.65 grams) having proved fatal to a child.

Peppermint camphor, also known as menthol, C₁₀H₂₀O, is a substance of closely similar properties which is obtained from the volatile oil of peppermint and related species of plants. Its important uses are too familiar to need mentioning. Although not so powerful a poison as laurinol, yet serious results may follow its careless internal use.

Fig. 169.-Laurel-camphor Tree (Cinnamomum Camphora, Laurel Family, Lauraceoe). Flowering branch, 1/3. (Baillon.)-Tree growing 12 m. tall; leaves thick; flowers yellow; berry dark red. Native home, China and Japan.