The incidence of B. influenzæ in cases of measles studied during the epidemic of influenza has been relatively high though never equaling that found in cases of influenza. As in normal men, the incidence in cases of measles has steadily increased during the period of the epidemic. Repeated throat cultures at weekly intervals in cases of measles have shown that approximately 80 per cent became temporary carriers of B. influenzæ at one time or another during the period of the epidemic. Many of these cases had influenza during the time that they were in the hospital. The carrier state in cases of measles was found to bear no relation to the acute stage of the disease since the number of carriers at the time of admission to the hospital was considerably lower than that found during convalescence as determined by repeated cultures in the same cases. Discussion The bacteriologic studies in cases of influenza described in this report fully support Pfeiffer’s claim that B. influenzæ is invariably present in the disease. It is particularly important to note that these results were obtained in early uncomplicated cases of influenza and are not dependent upon cultures made from cases complicated by pneumonia or obtained at autopsy. In view of this fact the tendency so apparent in much of the recent literature to relegate B. influenzæ to a place of secondary or minor importance in the disease seems hardly justifiable. It would seem that this tendency is largely dependent upon three factors: first, the failure of many to find B. influenzæ either during life or at autopsy in any considerable proportion of cases; second, the frequent failure to draw a clear distinction between influenza itself and the pneumonia to which it predisposes with a consequent overemphasis upon autopsy bacteriology where a considerable variety of secondary organisms have attracted particular attention; and third, an incorrect interpretation of the undoubtedly large number of B. influenzæ carriers found among normal individuals and those with other diseases during the period of the epidemic and to less extent in interepidemic times. Since the majority of workers who are thoroughly familiar with the technic of cultivating B. influenzæ have encountered little difficulty in finding it in a large majority of cases, it is felt that the considerable number of negative reports that have appeared can depend only upon the unfamiliarity of those who have failed to find it with the proper bacteriologic methods. This is quite apparent in many of the reports that have been published, and is not surprising in the face of the excessive demand for well-trained bacteriologists occasioned by the war.