Perforation of the stomach is most frequently caused by gastric ulcer, and may be said to be a characteristic symptom; but it usually occurs too late to be made use of in the treatment of the ulcer. It is occasionally the first symptom which calls the patient's attention to the fact that his stomach is and has been seriously diseased. By the agglutinations of the base of the ulcer with neighboring organs, through inflammatory processes, perforation can take place into these organs. The most frequent forms of perforation under such conditions are those into the liver, spleen or pancreas, but cases have occurred where perforation into the colon or pleural cavity has taken place, or even into the pericardium, the heart or lungs. Some time ago I saw a case of gangrene of the lung, the result of the perforation of a gastric ulcer into this organ. A few days ago I saw an interesting case, where an acute gastritis culminated in the vomiting of a large quantity of pus. The patient had been having high fever for a few days, with incessant vomiting and great tenderness in the epigastrium. Evidently an abscess had formed in the neighborhood of the stomach, and finally opened into this organ, with the given result. _Diagnosis._ There are two classes of characteristic symptoms--those originating from the exposure of nerve-endings, and those caused by ulceration into bloodvessels. The first class includes the painful sensations, the characteristic soreness, which occurs in about four-fifths of all the cases; the second class, the hemorrhages, occurring in only one-fourth of all the cases. You can readily see why pain occurs more often than hemorrhage. Even a very superficial abrasion may expose nerve-endings to the irritation of the food, while it takes a deeper ulceration to lay open a larger bloodvessel. In order to make a positive diagnosis, these two symptoms should be present. Vomiting of blood alone need not necessarily be caused by a gastric ulcer. There are a great many other conditions which may cause it. It should, however, put you on the guard, and can, in a great many cases, justify a diagnosis of probable ulcer of the stomach. The localized pain occurs, according to my experience, only in cases of ulceration of the stomach; that is, in gastric or peptic ulcer and in cancer of this organ. In order to differentiate between these conditions, it becomes necessary to observe whether the patient is cachectic or emaciated or not, and whether a tumor can be felt in the region of the stomach. But even these symptoms can be deceptive, as an abnormal hardness or resistance--the result of perigastritic infiltration--may occur in cases of simple ulcer, making the diagnosis almost impossible. This is true especially in cases of ulcer of the pyloric regions, while ulcers of the anterior wall of the stomach are rarely accompanied by such infiltrations.