Between September 15 and December 15, 1918, 867 cases of measles, admitted to the wards of the base hospital, were studied and handled according to the system outlined above. About one half of these cases appeared during the first month of the study. During this month hemolytic streptococci played a very insignificant rôle. This microorganism did not appear with alarming prevalence until after the wards had been thoroughly overcrowded. After the emergency, when better ward conditions were provided, S. hemolyticus carriers continued to develop in the wards and were removed when identified. The first S. hemolyticus carriers to develop in the wards were identified on October 8. The first case of streptococcus pneumonia developed on October 17, while streptococcus otitis as a complication of measles did not begin until a little later. During the latter two months of the study, S. hemolyticus became rampant in the wards. The streptococcus complications date their onset at some time during these two months. Table LXI shows the number of admissions to the measles wards by weeks and the patients among them found to be carrying hemolytic streptococci. It also shows the number of S. hemolyticus carriers developing each week among patients under treatment in the “clean” wards, as identified by throat cultures repeated at weekly intervals. For purposes of orientation, the number of cases developing streptococcus pneumonia and otitis media with its subsequent mastoiditis are given for each week during the period of observation. An admission to the measles ward can generally be regarded as an acute case of measles. There are a few exceptions to this statement and these are cases of measles treated in barracks and afterwards transferred to the base hospital. A relatively small number of such cases furnished 16 of the cases positive for hemolytic streptococci on admission to the measles ward. TABLE LXI S. HEMOLYTICUS CARRIERS IDENTIFIED BY THROAT CULTURE AMONG ADMISSIONS; THOSE DEVELOPING AMONG PATIENTS UNDER TREATMENT IN THE STREPTOCOCCUS “CLEAN” MEASLES WARDS; S. HEMOLYTICUS COMPLICATIONS ACCORDING TO THEIR DATES OF ONSET