=Bacteriology of Pneumonia Following Measles.=—When observations made during life are combined with the results of postmortem cultures, the bacteriology of 35 of the 56 cases is available and is as follows: Pneumococcus Type II atypical in 36 per cent, Type IV in 22.9 per cent, Type I in 2.8 per cent, Type III in 2.8 per cent, hemolytic streptococci in 22.4 per cent, and B. influenzæ in 88.6 per cent of these cases. =Otitis Media and Mastoiditis Complicating Measles.=—The occurrence of otitis media and mastoiditis complicating measles in patients harboring hemolytic streptococci in their throats has already been presented (Table LXIV). The bacteriology of these complications was not studied by this commission. The records of the base hospital laboratory at Camp Pike contain reports of twenty-nine cultures made at operation from pus in the middle ear and the mastoid bone. Hemolytic streptococci were found in 22 of these cases. Throat cultures were in accord with these positive findings in all except a few instances. The throat culture serves as a fairly reliable index of the bacterial nature of these complications. By combining our records of throat cultures with the results of the cultures from the lesions, hemolytic streptococci were obtained from 37 of the 48 cases of otitis media. In 23 cases of mastoiditis following the otitis media, hemolytic streptococci were demonstrated in all except 2. It is evident that the great majority of these complications were due to hemolytic streptococci. The relation between the appearance of hemolytic streptococci in the throat and the onset of the otitis is recorded in all except 4 of the 31 instances of otitis media occurring in patients with throat cultures positive for hemolytic streptococci. These four patients had positive throat cultures when first observed and represent the only patients who carried hemolytic streptococci when admitted to measles wards and developed complications. The first of these patients had been under treatment in an otologic ward during a month before measles developed. Measles caused a recurrence of disease of the ear with double mastoiditis requiring bilateral operation. Two other patients had been in the hospital ten and eleven days respectively before they were admitted to the measles ward; on admission to the ward otitis media was present in one patient and in the other it developed six days later. The fourth patient was admitted to the measles wards directly from the camp, and culture from the throat on the day of admission showed the presence of S. hemolyticus. Two weeks later at the time of onset of otitis media, culture from the throat contained no hemolytic streptococci. Repeated cultures during the next three weeks were negative. No complications of otitis media developed and no direct cultures from the ear are recorded. [Illustration: