The present report deals with a hitherto undescribed form of epidemic pulmonary disease occurring in newborn infants. Its peculiar symptomatology and pathology, as well as its epidemic character, clearly indicate the virus nature of its etiology. Characteristic cytoplasmic inclusion bodies were found in the bronchial epithelium in all fatal cases. An increasing number of reports on the subject of atypical pneumonia or virus pneumonitis in man has occurred in the literature during recent years.1That of Goodpasture and his co-workers2alone, however, deals with virus disease of the lungs in infancy. These authors reported finding intranuclear inclusion bodies in the bronchial epithelial cells in 3 cases of postmeasles pneumonia and in 1 case of postpertussis pneumonia. The differences between these cases and those reported in the present paper are detailed under the heading Differential Diagnosis. The 32 cases reported here occurred in rapid succession during the three winter