The appearance of the section of the pes hippocampi, a portion of the brain.

Cornu cervi, (from the Chaldee term karnah,) in chemistry, is the beak of an alembic; but it generally means the horn of the stag or hart, particularly of the male red deer, though the horns of the fallow deer are commonly employed. See Dama.

Hart's horn shaved gives out to water, by boiling, a soft insipid and flavourless jelly, in quantity about one-fourth of the weight of the horn. This jelly is used as a nourishing diet, and to obtund acrimony; it is usually mixed with the juice of lemons, or with wine or spice, according to the different circumstances of the patient. The Edinburgh college directs the following:

Jelly of hart's horn. Boil half a pound of the shavings of hart's horn, in six pints of water, to a quart: to the strained liquor add one ounce of the juice of lemon, or of Seville orange, four ounces of mountain wine, and half a pound of sugar; then boil the whole to a proper consistence.

The horns of deer are used for obtaining a liquor, salt, and oil, denominated liquor, sal, and oleum cornu cervi; but there is no observable difference betwixt one animal substance and another for this purpose, except in the different proportion of oil which they afford; hence the bones of oxen and other animals, the hoofs of horses, the horns of oxen, ivory, the shells of tortoises, hair, and silk, all afford nearly the same liquor, salt, and oil. See Alcali.

Hart's horn is said by former chemists to be prepared philosophically, when it is suspended in a still, while distilling any spirituous liquor; the horn being cut into thin slices, and exposed to the vapours, by which it is rendered white and friable. This preparation was accidentally discovered at Dresden, in Saxony, by Casper Pantzerus, an apothecary and native of Prussia. At present it is boiled till the black part separates, and then the inner white part is dried for use. Hoffman orders some alkaline salt to be put in the water when boiling, to soften the black part. This process frees the horns from their glutinous matter, and thus renders them friable.

By calcination, the earthy part is obtained most pure and perfect; its quantity about half the weight of the horn. The London college directs pieces of hart's horn to be burnt till they become perfectly white, then rubbed to a very fine powder, called cornu cervi calcina-tum, calcined hart's horn, phosphas calcis of the last edition of the Edinburgh Pharmacopoeia, which is to be powdered and levigated for use. As the intention of this operation is to separate the volatile parts, the heat cannot be too great: yet some caution is necessary in this respect, as by suddenly hardening the external parts, the internal are guarded from the action of fire; for the earth of hart's horn is not convertible into quick lime. The horns left after distilling the spirit, salt, and oil, are as proper as fresh ones; but they are a mixture of calcareous earth and phosphoric acid, and the weakest of the absorbents. The earth of all bones is similar. Hart's horn, by late experiments, is found to contain 27 parts of gelatine, 57.5 of phosphat of lime, and one of carbonate of lime, with about 14.5 of water. The bones of animals, sometimes substituted, contain also a small proportion of phosphat of magnesia. Burnt hart's horn, or burnt bones, are therefore slightly contaminated with these salts. The phosphat of lime has been recommended in rickets by M. Bonhomme, and used in France, it is said, with success; but it has seldom been given in England.

Solutions of this earth in vegetable acids are supposed to be restringent, and they probably act only by uniting with acid humours in the primae viae. The London college only directs the following decoction of hart's horn.

Take of burnt hart's horn prepared, two ounces; gum arabic, six drachms; distilled water, three pints; boil the water to a quart, and strain it. This is used as a common drink in fevers attended with laxity of the bowels, or after violent diarrhoeas.

Decoctum cretaceum. Take of chalk finely powdered, two ounces; of gum arabic, half an ounce; boil it in three pints to two of water; pour off the liquor from the heavier parts that fall to the bottom. This may be substituted for the former, but each would be useless if the gum was not an ingredient.

If a little cochineal is added, it is called decoctum ru-brum, red decoction. See Lewis's Materia Medica. Neumann's Chemical Works.

Cornu unicornu. See Unicornu.

Cornu fossile. See Unicornu.

Cornu cervinum. See Coronopus.