Several observations help to explain the occurrence of abscess in association with the pneumonia of influenza. The fissures which will be described in association with bronchiectasis represent traumatic ruptures of the bronchial wall consequent upon weakening by necrosis and over distention. They expose the injured bronchial wall and the alveolar tissue adjacent to it to infection by the microorganisms contained within the lumen of the inflamed bronchus. Occasionally a favorable microscopic section demonstrates the relation of pulmonary necrosis and consequent suppuration to injuries of the bronchial wall. Peribronchial fibrinous pneumonia occurs about the bronchi of which the epithelial lining has been destroyed, and when a fissure penetrates the bronchial wall fibrinous pneumonia is almost invariably found in a zone about the tear; it doubtless tends to limit the extension of the process. Occasionally, wide areas of necrosis occur within consolidated tissue near the site of the fissure (Autopsy 312 with S. hemolyticus and B. influenzæ, p. 254). Accumulation of polynuclear leucocytes between living and dead tissue may form a line of demarcation (Autopsy 387); finally, fairly large, irregularly formed, abscess cavities are found. Necrosis and beginning suppuration in contact with the lumen of the bronchus will be described in association with bronchiectasis (Autopsies 312, Fig. 24, and 423, p. 256). In the following autopsies upon individuals who have died with pulmonary abscesses, favorable microscopic sections have demonstrated abscess formation in contact with lesions which have penetrated the walls of small bronchi. They help to explain the pathogenesis of abscess in association with influenza. =Autopsy 376.=—H. M., white, aged twenty-four, a fireman, resident of Oklahoma, had been in military service one month. Onset of illness occurred October 1, ten days before his death; he was admitted to the base hospital on the fourth day of his illness with the diagnosis of bronchopneumonia. =Anatomic Diagnosis.=—Acute bronchopneumonia with patches of lobular and confluent lobular consolidation in both lungs and hemorrhagic peribronchiolar consolidation in right upper lobe; abscess in right upper lobe below pleura; fibrinopurulent pleurisy on right side; purulent bronchitis; bronchiectasis at base of left lobe. An irregular abscess, 2 x 1 cm., filled with creamy purulent fluid is separated from the interlobular surface of the right upper lobe by a thin membrane representing the pleura. The right pleural cavity contains 200 c.c. of turbid yellow fluid in which is soft fibrin. The bronchi contain purulent fluid in great abundance. The bronchi at the base of the left lower lobe are widely dilated, so that many small bronchi with no cartilage in their wall measure from 3 to 5 mm. in diameter.