(From Ichthyosis 4536 the scale of a fish, which it resembles). A harsh, dry, scaly, and almost horny texture of the skin, differing from leprosy by its not falling off in branny scales. Above and below the elbow and knee, Dr. Willan observes,that the scales are small, rounded, and papillary, of a black colour: the 5 H 2 papillae have short narrow necks, with broad irregular tops. On the rest of the body they are large and imbricated, sometimes divided by whitish furrows. The soles of the feet are dry and rough; the palms of the hands thickened and brittle, with large painful fissures, and the face is covered with bran rather than scales. The inner part of the wrists and hams, the inside of the elbow, and the furrow along each side of the spine, the inner and upper part of the thigh, are usually free. Some perspiration is necessary; and this seems occasionally to produce inflamed pustules. The disease appears to be constitutional, not hereditary. Two cases of a horny ichthyosis impeding the motion of the muscles are described in the 68th volume of the Philosophical Transactions.