John B. Deaver says the important points that have to be learned about this disease are that it is the most common intra-abdominal inflammation; that indigestion is often a forerunner, preparing the soil for the infection; that being an infectious disease and the most common infectious disease of the abdominal cavity, the appendix constitutes the avenue by way of which infection most commonly invades the upper abdomen. He considers acute appendicitis from the anatomical, etiological, bacteriological, and pathological standpoints: the points of the latter touched upon chiefly are in connection with peritonitis and abscess. The portions of the peritoneum most susceptible to infection are the diaphragmatic and enteronic. The differential points between a diffuse and a localized peritonitis are that in the former the pain is greater, the abdominal breathing more restricted and the rigidity and tenderness embrace a greater area of the overlying abdominal wall; upon auscultation the peristaltic waves are heard over a greater area and the abdominal breathing is less marked in the diffuse than in the localizing variety. In the early stages the tenderness and rigidity are best elicited by slight pressure. If the symptoms and signs, namely, pain, vomiting, fever, tenderness, and rigidity are interrupted, the diagnosis of acute appendicitis may be considered doubtful. Leucocytosis is of value as a confirmatory symptom when the patient reacts well to the infection. The most important point in the differential diagnosis is the distinction between acute cholecystitis and acute appendicitis. Acute pancreatitis, perforated ulcer, or perforated gall bladder, present symptoms so much more intense than those of acute appendicitis that they should not give rise to confusion. As to the treatment, the writer states most emphatically that in all cases of acute abdominal pain nothing in the shape of a purgative or aperient medicine should be given until the cause of the pain is understood. In his experience purgatives play the greatest amount of havoc in acute abdominal conditions; 90 per cent of cases of perforating peritonitis have been purged. In the presence of peritonitis and in the absence of operation the patient should be set up in bed, given nothing by mouth, not even cracked ice; he should be given enteroclysis by the Murphy method and have an icebag over the site of rigidity and tenderness; the icebag is useful to prevent the doctor from making too many examinations and for its local anesthetic affect. The idea that it has any effect in controlling inflammation is fallacious. In diffuse peritonitis, in the absence of peristalsis and of a definite point of localization, it is the writer’s practice to defer operation until the peritonitis becomes a localized or localizing one. The principles of anatomical and physiological rest, assisting the functions of the peritoneum, absorption and exudation, are defeated by any treatment