lichen: Of ammoniac perfume, of the flour of bitter vetch, of the flour of lupines, equal parts; add to vinegar. * * * * * COMMENTARY. See Hippocrates (de Humor., de Affect.); Galen. (Isagoge, de Med. sec. loc. v); Oribasius (Morb. Curat. iii, 59); Aëtius (viii, 16); Actuarius (Meth. Med. ii, 11); Marcellus (19); Nonnus (236); Celsus (v, 28); Pliny (H. N. xxvi, 2); Serapion (v, 2); Avicenna (iv, 7, 3, 3); Alsaharavius (Pract. xxxi, 7); Rhases (Divis. 117); Haly Abbas (Pract. iv, 10.) Dr. Bateman states, that the exact acceptation of the term lichen cannot well be ascertained from the writings of Hippocrates; but Dr. Willan affirms that he restricted it to a papular eruption on the skin. In the ‘Isagoge,’ usually ascribed to Galen, two varieties are described, the lichen mitis, and the lichen agrius, in both of which scales are formed upon the skin, which appear almost ulcerated when they are removed. They are to be cured by cholagogues internally, and liniments externally. Galen remarks the tendency of the disease to pass into lepra and scabies. To prevent this, he directs desiccative and detergent applications, for the preparation of which he gives various prescriptions. One of these, which bears the name of Pamphilus, is a powerful escharotic, composed of orpiment, realgar, burnt copper, and cantharides. (Med. sec. loc. v.) He says it affects principally the chin, but is apt to spread over the face. Oribasius, Aëtius, Actuarius, and Nonnus, treat of the complaint in nearly the same terms as our author. Their translators improperly render it by impetigo. Leo ascribes the origin of the disease to hot and corrupted blood. Celsus describes the lichen of the Greeks by the name of _papula_, of which he mentions two varieties. In the first, he says, the skin is merely roughened by small pustules, is reddened and slightly corroded; the middle is somewhat smoother, and it spreads slowly, generally in a round shape. This description would seem to apply to the _lichen circumscriptus_ of Drs. Bateman and Willan, although the latter author thinks that it possessed a wider signification. The second variety, he says, is called ἀγρία by the Greeks, and in it the skin is more rough, red, and corroded. The more it departs from the circular form the less tractable is it, and, unless removed, it is said to pass into impetigo. From this account it is clear that the lichen of the Greeks, in its original form, was different from impetigo. Celsus recommends friction with the saliva of a fasting person, and also mentions a composition containing natron, frankincense, sulphur, &c. The translator of Serapion improperly renders the name of this affection by the term impetigo. His remedies are nearly the same as our author’s, namely, the saliva of a person fasting, compositions containing hellebore, natron, the ashes of starlings, &c.