If the rupture is large, a single linear, or a T-shaped incision, exposing the base of the tumour, will be sufficient to allow the requisite dilatation of the opening to be made. It is not at all necessary in every case to open the sac of the peritoneum. If required, it must be done with great caution, as the sac is generally very thin. In cases where the hernia is chiefly omental, the sac should be opened, lest a knuckle of bowel be inclosed and strangulated in the omentum. OBTURATOR HERNIA is an extremely rare lesion, and a large proportion of the recorded cases were discovered only after death. When diagnosed during life and strangulated, some have been reduced by taxis, and only a very few cases have been operated on, some with success. It is not likely that a diagnosis could be made, except in very emaciated patients, in whom pain at the obturator foramen was a prominent symptom, and in whom it could be ascertained positively that the crural ring was empty. An incision over the tumour, sufficient to allow the pectineus muscle to be exposed and divided, is necessary. The hernia may then be reduced without opening the sac, if recent; if of long standing, the sac must be opened. One case is recorded by Dr. Lorinzer, in which, after strangulation for eleven days, he opened the sac and found the bowel gangrenous. The patient had a fæcal fistula; but survived the operation for eleven months. Nuttel, Obrè, and Bransby Cooper have each diagnosed and treated such cases.[146] Other forms of hernia are so rare, and the treatment of each case must necessarily vary so much in its circumstances, as not to require or admit of any detailed account of the operations requisite for their relief. OPERATIONS FOR THE RADICAL CURE OF HERNIA.--The inconveniences and discomfort caused by even the best-adjusted trusses or bandages, the unsatisfactory support they afford, and the risk of their slipping and allowing the hernia to escape, have given rise to many attempts to cure hernia by operation. Even to enumerate these would be quite beyond the limits of the present volume; suffice it to classify a few of the most important of them according to the principle involved in each, and then give a very brief account of the method of operating which seems to be at once the most scientific, least dangerous, and most permanently useful. The question at issue is briefly this. We have, in a hernia, the following condition:--The walls of a great cavity are at one or more points specially weak, the contained viscera have protruded, either by extension and stretching of a natural opening, or by the formation of a new breach in the walls, and, in protruding, they have brought with them as a covering a serous membrane, extremely extensible, highly sensitive to injury, and, when injured, certain to resent it by severe, spreading, and dangerous inflammation. Do we desire to remedy this protrusion, we may act--