former are more liable to become rancid by long keeping, and ought, therefore, to be applied when in a fresh state.
In the preparation of ointments, the fat and resinous substances ought first to be melted in a gentle heat, over which they should be carefully stirred, when such dry ingredients as may be necessary (being finely pulverized), must be gradually sprinkled in; till, on diminishing the heat, the mixture become stift.
Simple Ointment consists of five parts of olive-oil, and two parts of white-wax, thoroughly incorporated.
Ointment of Hog's-lard is prepared by triturating two pounds of hog's-lard with three ounces of rose-water, till they are perfectly mixed. The whole should now be melted over a moderate fire, and suffered to subside, when the lard must be poured off, and constantly stirred, till it become cold.
Both these ointments may be used for softening the skin, and healing chaps. The former, however, being of a more uniform consistence, is preferable to the latter: but too large a quantity of either ought not to be prepared at one time; because, when they have been kept for some months, or even a few weeks, they lose their healing properties.
Van Mons has devised a new, and less troublesome, method of compounding ointments and plasters, in which fresh herbs, or their expressed juices, are employed as ingredients. The vegetable sap ought previously to be strained, and deprived of all feculent matters: next it is placed over a very moderate fire, in a shallow earthen vessel, where it is evaporated nearly to dryness: this coagulated extract is now baked or dried in an oven, so that it may be reduced to powder; in which state it is again exposed to the fire, together with the fat or oil intended for its vehicle, till the humidity is completely evaporated.—For a cheap and useful family ointment, see Burns, vol. i. p. 398.
Old-age. See Longevity.
OLIBANUM, a gummy-resinous substance, obtained from the Juniperus lycia, L.—It is imported from the Levant, or the East Indies; consisting of drops or tears, resembhng those of Mastich, though rather larger: they are of a pale-yellowish, and sometimes reddish-colour, possess a moderately warm pungent taste, and a strong, though not agreeable smell.
Olibanum consists of about equal parts of gummy and resinous matters; the former of which are soluble in water, and the latter in rectified spirit.
Many virtues were formerly attributed to this drug, which it does not really possess. According to Riverius, however, it is highly serviceable in pleurisies, especially those of the epidemic kind; for which purpose, he directs a scooped apple to be filled with a drachm of olibanum, then covered and roasted under the ashes; this is to be taken for a dose, with three ounces of carduus water, and the patient to be covered up warm in bed: thus, in a short time, either a profuse perspiration, or a gentle diarrhœa ensues, and the disease in consequence disappears.
OLIVE-TREE, or Olea, L. a genus of plants, consisting of six species, the principal of which is the Europæa, or Common Olive-tree.—It is a native of the Southern
