Ointments

Ointments are fatty substances intended to be applied to the skin by rubbing in, and having the consistence of butter. The material employed as a basis for the ointment varies considerably, and as a rule the activity and action are entirely due to the substance incorporated with the basis. The most generally used basis is lard, either alone or mixed with wax, &c., to give it more consistence. To avoid rancidity the lard is usually melted previously with gum-benzoin, and is then known as benzoated lard. Although lard is readily absorbed by the skin, yet in this respect it is surpassed by sheep's wool fat and Oleic Acid (q.v.). The former of these, when incorporated with water, forms an excellent ointment base, smooth, and in every way suitable. So also some of the unctuous oleates are used with great advantage. Soft paraffin, known in commerce under a number of names, has also been used for ointments and does not turn rancid, but on the whole its use is not extending. As nearly all substances may be made into ointments, there is no limit to their number, but perhaps the best known are Zinc Ointment (q.v.), Boracic Ointment, and the Red and White Precipitate Ointments (see PRECIPITATE OINTMENT). In all cases the greatest care is required to ensure that the active principle is rubbed perfectly smooth with a small quantity of oil or lard before adding the bulk of the ingredients, otherwise the production of a homogeneous ointment free from grit is impossible. See COLD CREAM.