Pour cold water (12) on tar (6), stir frequently for twenty-four hours, and then throw the water away. Pour on boiling distilled water (50), stir for fifteen minutes, and then set aside for thirty-six hours, stirring occasionally. Decant, filter, and add sugar, 40 parts.

Action and Use. - Tar acts as a stimulant both to the skin and to mucous membranes. It is used in chronic scaly skin-diseases, such as psoriasis, and the scaly stages of eczema. It is an efficient agent in relieving the itching of chronic skin-affections. The best way of applying tar is in the form of distilled wood-tar, beech, birch, or juniper tar. These should be applied carefully with a stiff brush, and are found useful in chronic eczema, psoriasis, the prurigo of Hebra, lupus erythematosus, lichen ruber, and ringworm. They may be made into ointment with vaseline or lard. In the form of tar-water or of vapour, it is useful in chronic bronchitis and phthisis.