CERA. L.E.D. Wax.
It is admitted into the list of the Materia Medica under two forms, viz.
1. Cera Flava. Yellow or Unbleached Wax.
Qualities. Odour, faintly honey-like; it is brittle yet soft; when chewed, it does not, if pure, adhere to the teeth; it melts at 142°, and burns entirely away. Chemical Composition. It is the honey-comb of the bee melted with boiling water, pressed through cloth bags, and ultimately cast into round cakes for the market. Whether it be an animal product, or a vegetable substance merely collected by the bee, has been a question of dispute; the former opinion is probably correct, although wax is certainly produced as a secretion by many plants. The yellow wax contains a portion of pollen which imparts its colour to it, and increases its fusibility. Solubility. It is insoluble in water, and in cold alcohol or ether, but it is soluble in boiling alcohol and ether, in fixed oils, and in alkalies. Uses. It is chiefly employed in the composition of external applications. Adulterations. Earth or peas-meal may be suspected when the cake is very brittle, and the colour inclines to grey; Resin is detected by putting it in cold alcohol, which will dissolve the resinous part without acting on the wax. Tallow is discovered by the greater softness and unctuosity of the cake, and by its suffocating smell when melted; when this latter substance is employed, turmeric is added to disguise its paleness.
2. Cera Alba. White, Bleached, or Virgin’s Wax.
Qualities. This substance differs only from the former, in being colourless, harder, heavier, and less fusible. Uses. It is said to be demulcent, and very useful in dysentery, but it is rarely used. Forms of Exhibition. It may be formed into a mixture by melting it with one-third of its weight of soap, and then gradually adding to it any mucilaginous liquid. Adulterations. White Lead may be detected by melting the wax in water, when the oxide will fall to the bottom of the vessel; tallow may be suspected when the cake wants its usual translucency.
CERATA. L.E. Cerates.
These compositions are characterized by a degree of consistence, intermediate between that of plasters, and that of ointments. As this consistence is obtained from the wax which they contain, they very properly derive from that substance the generic appellation of Cerates.
Ceratum Calaminæ. L. (Ceratum lapidis Calaminaris. P.L. 1787. Ceratum epuloticum. P.L. 1745). Ceratum Carbonatis Zinci Impuri. E. Unguentum Calaminare. D.—These preparations have been long known under the name of Turner’s Cerate; they form the basis of many extemporaneous cerates, in some of which nitric oxide of mercury, in the proportion of ʒj of the oxide to ℥j of cerate, and in others, the liquor of sub-acetate of lead, are introduced. By the former combination we obtain a very useful application to indolent and ill-conditioned ulcers, a valuable stimulant for inducing an action conducive to the regeneration of parts. By the latter combination we derive a remedy highly extolled by our most experienced surgeons, in the cure of burns and scalds.
Ceratum Cantharidis. L. The basis of this preparation is spermaceti cerate six parts, to which is added, of powdered flies one part: as it is intended to promote a purulent discharge from a blistered surface, it may be reduced in strength according to circumstances.