The earlier modern writers, such as those of the Schola Salernitana, Platearius, Guy of Cauliac, and Lanfrancus, jumble together the Latin and Arabian names, so as to produce no ordinary degree of confusion. Guy of Cauliac, indeed, maintains that there is little necessity for distinguishing lepra, alphos, melas, impetigo, gutta rosacea, and such like cutaneous complaints from one another, as they are all varieties of the same disease. Lanfrancus, however, is of a different opinion. (i, 3, 6.) SECT. III.—ON LICHEN. Lichen is formed by the mixture of a thin and acrid ichor with other gross humours, and passes readily into leprosy and psora; wherefore it requires to be treated by the most desiccative applications. After general depletion, if necessary, the following simple medicines will be proper: chick-peas, hellebore, the urchin which dwells among rocks, pitch mixed with cerate and rosin, the dung of the land crocodile, that of starlings fed solely upon rice. And many have cured the complaint when occurring on the chin, or other parts of the body, by this application alone: take several grains of wheat and place upon a stithy red-hot, and taking the fluid which flows from them while yet warm, anoint the part affected with lichen. The lichen of children is to be rubbed frequently with human saliva. The gum of the plum tree, when rubbed in, is beneficial in these cases. When the complaint is protracted, the leaves of the chaste tree, triturated with vinegar, are to be applied, or the leaves of capers in like manner. The following are compound applications: Dissolve sulphur with rosemary in vinegar, or with ammoniac, and anoint. A trochisk for lichen: Of artificers’ glue, dr. iv; of frankincense, dr. iij; of vinegar half a cyathus; dissolve in vinegar, and anoint.—_Another_: Of chalcitis, of gum, of each, dr. viij; of sulphur vivum, of misy, of each, dr. vj; of the flakes of copper, of acacia, of each, dr. ij; anoint with vinegar.—_Another_: Of sulphur vivum, of spuma nitri, of each, dr. iv; of the seeds of rosemary, lx; triturate with vinegar, and anoint only the part which is affected, not touching the sound skin. When dry, wash it away with cold water.—_Another_: Of white hellebore, dr. viij; of the flour of lupines, of burnt shell-fishes called buccina, of natron, of each, one chœnix; rub with it dry. They call that variety of lichen _agrius_ which is nowise remedied by moderately desiccative applications, and is exacerbated by more acrid ones. These cases are therefore to be treated by applications which are sufficiently strong, without being pungent, such as this: of horned poppy, of frankincense, of alcyonium, of bitumen, of sulphur, of gum, of each, oz. j; anoint with vinegar. Boil African pitch with vinegar, and, when dissolved, anoint.—_Another_, for lichen and prurigo: Of copperas, of sulphur vivum, of natron, of frankincense, equal parts; use for lichen with vinegar, and for prurigo with wine.—_Another_, for