_Abrasion_ of the conjunctival covering of the cornea is produced by accident, or follows incited action of the vessels. The abraded surface either ulcerates, or contracts and heals kindly, with or without opacity of the part. Breach of surface in the cornea,—whether an ulcer, an abrasion, or a raw surface, caused by the giving way of a pustule, or of a small abscess,—is constantly liable to irritation, on account of not being protected by mucous membrane and mucous discharge: even the contact of the tears irritates, and keeps up inflammatory action in the membranes. When the ulcerative process ceases, lymph is effused, and a grayish halo forms around the sore; the ash colour of the surface of the sore disappears, and is succeeded by florid granulations, extremely minute, which fill up the cavity; cicatrisation follows in due time, with subsidence of all the symptoms and appearances of inflammation. There remains, however, an opaque speck of a pearly hue corresponding to the sore, but occupying rather less space. When the cornea is perforated by ulceration, the sore sometimes shows no disposition to heal, becoming a fistulous aperture through which the aqueous humour is from time to time discharged. By this condition of parts vision is much impaired, the cornea being always more or less flaccid. Touching the fistulous opening with the nitrate of silver, reduced by scraping to a very fine point, will often promote a healthy action in the tissue, and effect adhesion of its sides.