​LANOLIN (Lat. lana, wool, and oleum, oil), the commercial name of the preparation styled adeps lanae hydrosus in the British Pharmacopoeia, and which consists of 7 oz. of neutral wool-fat (adeps lanae) mixed with 3 fluid oz. of water. The wool-fat is obtained by purification of the “brown grease,” “recovered grease” or dégras extracted from raw sheep’s wool in the process of preparing it for the spinner. It is a translucent unctuous substance which has the property of taking up large quantities of water and forming emulsions which are very slow to separate into their constituents. Owing to the ease with which it penetrates the skin, wool-fat both in the anhydrous form and as lanolin, sometimes mixed with such substances as vaseline or fatty oils, is largely employed as a basis for ointments. It is slightly antiseptic and does not become rancid.