When bronchiectasis occurs throughout a whole lung, usually the left, or in both lungs, the lesion is more advanced and conspicuous (Fig. 26). There is diffuse dilatation of small and medium-sized bronchi. Dilated bronchi with deeply injected mucosa and filled with yellow mucopurulent fluid, are seen throughout the sectioned lung. A bronchus cut longitudinally may have a nearly uniform diameter of from 5 to 9 mm. for a distance of 5 or 6 cm., maintaining this diameter to within 1 cm. of the pleural surface, where normally only small bronchi occur. More advanced bronchiectasis is represented by the occurrence of spherical bronchiectatic cavities, having a diameter from 1 to 2.5 cm. In some instances there have been two or three of these cavities but occasionally there may be many. Cylindrical dilatation of the bronchi usually occurs widely distributed in the lungs. In Autopsy 440 a small bronchus, cut longitudinally, was dilated to a diameter of 5 mm. for a distance of 5 cm. and terminated in a spherical cavity 2 cm. in diameter; there was another smaller spherical cavity nearby and dilated bronchi occurred elsewhere. In Autopsy 467, in the upper part of the lower lobe, two spherical cavities 1 and 1.5 cm. in diameter communicated with a bronchus of medium size. Autopsies with bronchiectasis are listed in the order of the duration of illness to show the parallel increase in the severity of the lesion (Table LI). In 2 instances (Autopsies 244 and 314) bronchiectatic cavities surrounded by firm fibrous tissue have evidently existed before the onset of the fatal illness, which has lasted in one instance approximately four and in the other six days; these autopsies have been omitted from the table. The table shows that bronchiectasis observed within twelve days after onset of illness with symptoms of influenza is moderately advanced and almost invariably limited to the left lower lobe and usually to the base of the lobe. Advanced dilatation, indicated by the formation of spherical or cylindrical cavities, occurs with increasing frequency as the duration of the respiratory disease increases. Bronchiectasis has been almost invariably associated with purulent bronchitis. The dilated bronchi contain mucopurulent material and throughout the lungs the same condition is usually widespread. Among 137 instances of purulent bronchitis bronchiectasis consequent upon influenza has been present in 50. TABLE LI