=Clinical Features.=—Purulent bronchitis following influenza began insidiously without any prominent symptoms to mark its onset. About the third or fourth day of influenza, when recovery from the primary disease might be looked for, the patient would begin to cough more frequently, raising increasing amounts of mucopurulent sputum. This sputum was yellowish green in color, copious in amount, and often somewhat nummular in character, sometimes streaked with blood. These symptoms were accompanied by the appearance of coarse, medium and fine moist râles more or less diffusely scattered throughout the chest and usually most numerous over the lower lobes. The percussion note, breath and voice sounds, and vocal and tactile fremitus remained normal. There was no increase in the respiratory rate or pulse rate, and cyanosis did not develop in the absence of a beginning pneumonia. Many such cases, of course, developed bronchopneumonia; in this event areas showing diminished resonance, suppressed breath sounds, and fine crepitant râles with the “close to the ear” quality would appear, the respiratory rate would become increased and cyanosis would become evident. In those cases of purulent bronchitis not developing pneumonia, a moderate elevation of temperature, rarely above 101° F., and irregular in character usually occurred and persisted for a few days or a week. Many cases maintained a persistent cough, raising considerable amounts of sputum throughout the period of their convalescence in the hospital, which was often considerably prolonged when this complication of influenza occurred. Although no clinical data are available on such cases over a prolonged period of observation, it seems probable that some of them, at least, had developed some degree of bronchiectasis. This would seem all the more probable, since many cases of pneumonia following influenza showed at autopsy extensive purulent bronchitis with well-developed bronchiectasis. Bronchiectasis will be discussed in greater detail in another section of this report. It is this group of cases with more or less permanent damage to the bronchial tree that makes this type of bronchitis following influenza a serious complication of the disease. Pneumonia The opportunity presented for a correlated study of the clinical features, bacteriology, and pathology of pneumonia following influenza throughout the period of the epidemic at Camp Pike from September 6, 1918, to December 15, 1918, made it evident that this pneumonia could be regarded as an entity in only one respect, namely, that influenza was the predisposing cause. Clinically, bacteriologically, and pathologically it presented a very diversified picture ranging all the way from pneumococcus lobar pneumonia to hemolytic streptococcus interstitial and suppurative pneumonia with the picture modified to a varying extent by the preceding or concomitant influenzal infection.