This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
These are varieties of beeswax (cera); the yellow being the crude wax as prepared from the comb; the white, the same purified by a bleaching process, which deprives it of colouring and odorous matter. The white wax is that usually preferred in the preparation of ointments, cerates, and plasters, for which purpose it is much used. its advantages are that it is perfectly bland, and, by its physical properties, serves to give a proper consistence and tenacity to the preparation. Tho protective compounds, of which it is an ingredient, are the ointment of rose water and spermaceti cerate, just described, and the following.
Simple Cerate, or Cerate of Lard (Ceratum Simplex, U. S. 1850; Ceratum Adipis, U. S.), is made by melting together two parts of lard and one of white wax. This is the preparation most commonly used for dressing blisters, excoriations, wounds, and ulcers, when the purely protective influence is required. Peculiar care should be taken to prepare it from perfectly sound materials, and afterwards to keep it sweet.
Simple Ointment, or Ointment op Lard (Unguentum Simplex, U. S. 1850, Br.; Unguentum Adipis, U. S.), differs from the preceding preparation only in the proportion of its ingredients; four parts of lard being employed to one of wax, instead of two parts, as in simple cerate. The proportions in the cerate are adapted to the purposes of a firm covering for ulcers, etc., in which the unctuous matter will retain its place, and not, by melting with the heat of the body, sink into the dressings. The ointment is much softer, and, though it may be used for the same purposes, especially in cold weather, is more frequently employed as a vehicle for other medicines, to be applied by inunction, or spread on linen or patent lint.
Soap Cerate (Ceratum Saponis, U. S.) is now made by melting together soap plaster, white wax, and olive oil. it is a handsome preparation, and serves for a protective dressing, in all cases in which a gently sedative impression from lead may be at the same time indicated; the lead plaster being the basis of that employed.