A purified distillate from American petroleum, consisting of hydrocarbons, chiefly of the marsh-gas series [C5H12; C6H14, and homologous compounds], having a specific gravity from 0.670 to 0.675, and boiling at 50° to 69° C. (122° to 140° F.).

Benzin should be carefully kept in well-stoppered bottles or cans, in a cool place, remote from lights or fire.

Characters. - A transparent, colourless, diffusive liquid, of a strong, characteristic odour, slightly resembling that of petroleum, but much less disagreeable; neutral in reaction. It is highly inflammable, and its vapour, when mixed with air and ignited, explodes violently.

Solubility. - It is insoluble in water, soluble in about 6 parts of alcohol, and readily so in ether, chloroform, benzene, and fixed and volatile oils.

Reactions. - Benzin, when evaporated upon the hand, should leave no odour, and when evaporated in a warmed dish should leave no residue (absence of heavy hydrocarbons). When boiled a few minutes with one-fourth its volume of spirit of ammonia and a few drops of test-solution of nitrate of silver, the ammoniacal liquid should not turn brown (absence of pyrogenous products, and sulphur compounds); and it should require 6 parts of officinal alcohol to dissolve it (difference from benzene). If five drops are added to a mixture of 40 drops of sulphuric acid with 10 drops of nitric acid, in a test-tube, the liquid warmed and set aside for half an hour, and then diluted, in a shallow dish, with twice its volume of water, it should not have the bitter-almond-like odour of nitro-benzene (absence of benzene).

Dose. - As a vermifuge, 30 minims.

Uses. - It is a good solvent for fats, resins, caoutchouc, and some of the alkaloids. It has been used externally as a sedative in prurigo and other cutaneous diseases, and to relieve the itching in urticaria, and internally as a vermifuge for tape-worm.