The thinning of the nail, by scraping or with the drill, can also be accomplished with sodium sulphide. A sufficient quantity of the sulphide is added to starch paste to make it swell; this, when applied (use a wooden applicator) to the thickened nail, will cause the nail to disintegrate. By touching the surface with the applicator, one can determine the depth of nail destroyed before washing off the excess sulphide. +Radical Treatment of Hypertrophy.+ When the thick nail has cut into the lateral fold and actual ulceration has occurred, it becomes necessary to remove the down-curved edge. Under local anesthesia, an incision is made through the nail, a little to the side of the inflamed area, and is carried well back through the matrix. A curved incision, outside of the infected fold, meets the first incision in front and back of the nail. All the tissue between is removed in one piece, including the offending portion of nail with its matrix and the nail fold with all granulation tissue. This wound may be brought together by catgut sutures, or may be allowed to heal by granulation. This operation suffices to prevent further trouble at the nail edge, but does not prevent the discomforts due to a long, distorted, horny nail. Total removal of the nail with its matrix is the only radical cure. (See “_Local Anesthesia”_). +Inflammation of the Matrix (Onychia).+ As a result oftraumatism in unhealthy individuals, inflammation and suppuration sometimes occur at the root of a nail and in the contiguous portion of matrix (“run-around”), and often stubbornly continue unless the loosened, sharp edge of the buried nail be carefully trimmed away from time to time, and a little iodoform gauze be employed to press back the inflamed tissues. From lateral hypertrophy of a toe-nail the sharp lateral edge becomes imbedded in the lateral fold, or from improper lateral compression of the toes, the same portion of soft tissues is forced up against the margin of the nail. In either case, inflammation, suppuration, and ulceration ensue, resulting in the formation of red, exuberant, excessively painful granulations, constituting the condition called _ingrowing toe-nail_, though more correctly it should be termed “up-growing pulp.” Sometimes both edges, or even the whole matrix, become involved, producing pain on any movement of the member. When inflammation and ulceration of the whole matrix occur, especially where a finger is involved, the condition is termed _onychia maligna_, which attacks only those in depressed health. +Treatment.+ The palliative treatment suggested for ingrown nail is indicated for all inflammations of the matrix, as far as the disinfection or removal of the portion of nail producing irritation is concerned, but in onychia maligna the whole nail usually requires removal under local anesthesia, with destruction of the matrix by caustics, or by curetment. Chapter XV +TUMORS AND CYSTS+ +TUMORS+