To obtain further light on this question the type of pneumococcus present in the mouths of 46 consecutive cases of early uncomplicated influenza was determined by the mouse inoculation method at time of admission to the receiving ward of the hospital before the patients had been associated, with the purpose of determining if cases among this group which subsequently developed pneumonia might be shown to have acquired a pneumococcus which they did not carry at time of admission. This group of patients was treated in a special ward set apart for the purpose. The patients were assigned to beds in rotation and confined in bed until thoroughly convalescent. Beds were well separated and cubicles, masks and gowns were in use. Cultures were made from the ward personnel. By these procedures an accurate record was kept of all sources of pneumococcus infection. The types of pneumococcus found in the mouths of these patients at time of admission are shown in Table XXV. TABLE XXV TYPES OF PNEUMOCOCCI IN THE MOUTHS OF INFLUENZA PATIENTS ═══════════════════════════════════════════════════════════════════════ PNEUMOCOCCUS NUMBER PER CENT ─────────────────────────────────────────────────────────────────────── Pneumococcus, Type I 0 0 Pneumococcus, Type II 0 0 Pneumococcus, II atypical 1 2.2 Pneumococcus, Type III 0 0 Pneumococcus, Group IV 25 54.3 No pneumococci found 20 43.5 ─────────────────────────────────────────────────────────────────────── Only 1 patient in this group developed pneumonia. At time of admission he had no pneumococcus in his mouth as determined by inoculation of a white mouse with his sputum. Examination of the sputum by the same method at time of onset of pneumonia three days after admission showed Pneumococcus Type III. The only ascertainable source of infection in this case was one of the ward attendants who carried Pneumococcus Type III in his throat in sufficiently large numbers to be demonstrable by direct culture and who frequently came in contact with the patient. In this instance the development of pneumonia was probably due to contact infection. An extensive study of this nature would be necessary to determine in what proportion of cases pneumonia following influenza is caused by secondary contact infection and in what proportion to autogenous infection. It is at least evident that contact infection with a type of pneumococcus found in the mouth of normal individuals may occur in influenza and be responsible for the development of pneumonia. Therefore every precaution should be taken to prevent it.