Bronchi which are the site of acute inflammation have lost their epithelium wholly or in part, and deep fissures penetrate the entire thickness of the bronchial wall, extending into the surrounding lung tissue which is the site of fibrinous pneumonia. In some instances plugs of fibrin within the alveoli are bisected by these tears. There is some superficial necrosis along the edge of each fissure, in several places extending outward from defects in the walls of small bronchi dilated to approximately 1.5 mm. There are wide patches of necrosis affecting both alveolar walls and contents of alveoli and extending 2 mm. into the lung tissue. When a fissure has penetrated from the lumen of the bronchus into necrotic tissue (Fig. 21), polynuclear leucocytes have accumulated within the necrotic tissue, disintegration of tissue occurs, and a small cavity communicating with the bronchus is formed. =Autopsy 423.=—C. H., white, aged twenty-five, resident of Oklahoma, had been in military service one month. Death occurred sixteen days after onset of influenza. =Anatomical Diagnosis.=—Chronic bronchopneumonia with peribronchiolar consolidation throughout right lung and in left lower lobe; right purulent pleurisy; purulent bronchitis; bronchiectasis at base of left lung. The right lung weighs 1,260 grams; in the upper lobe are yellowish gray nodules having the appearance of tubercles clustered about small bronchi; in places similar nodules occur upon a background of pinkish gray consolidation occupying the greater part of the lower lobe. Bronchi contain purulent fluid. The left lung weighs 760 grams; it is edematous and small, yellowish gray nodules of consolidation in the lower lobe are clustered about terminal bronchi. Bronchi at the base of the lower lobe are dilated. Bacteriologic examination shows the presence of hemolytic streptococci in the blood of the heart; hemolytic streptococci and B. influenzæ in the lung. Microscopic examination shows that the walls of the bronchi are infiltrated with lymphoid and plasma cells; these cells are very numerous in peribronchiolar patches of consolidation. A small bronchus 1 mm. in diameter has squamous epithelium along one side; on the opposite side, the wall is completely absent and there is superficial necrosis of exposed alveoli filled with fibrin. A deep fissure passes from the bronchus into the consolidated tissue; its edges are necrotic and it is filled with polynuclear leucocytes. A small cavity in contact with the bronchus has been formed. In another part of the lung a distended bronchus has lost its epithelium on one side, and here alveoli filled with fibrin form the wall of the bronchus which is filled with leucocytes. Extending outward from the eroded wall is a focus of necrosis where both alveolar walls and contained exudate have lost their nuclei.