(b) Eleven of the patients entering as positives became negative, 10 after one week and 1 after two weeks.

This group of cases furnishes no data concerning the duration of the “carrier” state, since all cases were positive when first observed. In 30 per cent of instances, hemolytic streptococci disappeared within the first two weeks of observation.

Groups II to VIII include 205 patients who became positive at some time during their stay in the hospital. The arrangement in groups depends upon the length of time the patients remained in the hospital before acquiring S. hemolyticus. Ninety-five of these patients had no further cultures after the initial positive culture. Fourteen appear as “irregular,” as defined above. These two classes of cases are omitted in the following summary of these groups. The initial positive culture is arbitrarily considered the day of infection and subsequent cultures mark off weekly intervals.

(a) Thirty-nine patients had acute infections due to hemolytic streptococci. Thirteen of these patients passed from observation after their initial positive culture. The cases with repeated cultures after initial positive may be summarized as in Table LXIX.

The records within this small group of cases indicate that hemolytic streptococci tend to disappear with the passing of the acute infection.

(b) One hundred and sixty-six contact “carriers” are included in Groups II to VIII. Eighty-two of these passed from observation after their initial positive culture and 14 appear as “irregular.” The cases with repeated throat cultures after the initial positive are summarized in Table LXX.

These records indicate that contact carriers in great part harbor hemolytic streptococci during short intervals. A longer period of observation after the disappearance of hemolytic streptococci would have been desirable in many instances. Some patients were followed with consistently negative cultures during three, four and five weeks after hemolytic streptococci had disappeared.

It is difficult to explain those instances in which negative cultures are interposed between positives. Where one negative interrupts positive cultures, it is possible that the throat culture failed to demonstrate hemolytic streptococci which were present. Such cases in this series fall within the limits of the percentage error of throat culture identification. Where two or three, or even four negative cultures intervene, reinfection is not impossible.

Relation of S. Hemolyticus “Carriers” to the Complications of Acute Respiratory Diseases.—In the present study of measles it has been shown that pneumonia following measles has been no more common in “carriers” than in “noncarriers.” Nevertheless, pneumonia occurring in badly infected wards has been modified by streptococcus complications.

More cases of otitis media have appeared in “carriers” than in “noncarriers.” The possibility that mild otitis media, which would ordinarily pass unnoticed, might become evident as the result of streptococcus invasion must be considered. Levy and Alexander have made an important contribution to our knowledge of the rôle of hemolytic streptococci in measles. They find that “carriers” of hemolytic streptococci among measles patients are especially predisposed to complications following measles.

Their cases were drawn from a camp population highly saturated with S. hemolyticus “carriers.” In the organization from which 89 per cent of their patients with measles came, there were 83 per cent hemolyticus “carriers” among men on duty. Among patients with measles, throat cultures were positive for hemolytic streptococci on admission in 77 per cent. It is evident that all patients with measles have been exposed to hemolytic streptococci during the first day or two after admission. Failure to carry streptococcus would appear to be dependent upon ability to resist it rather than upon lack of opportunity for acquiring it. Of 388 cases observed by Levy and Alexander only 79 were “noncarriers” of hemolytic streptococci on admission, and of these, 27 became positive while under observation; only 52 remain as “noncarriers” of hemolytic streptococci. This small group must be regarded as a highly selected one, composed of individuals more than ordinarily resistant to hemolytic streptococci and perhaps to all complications of measles. The chances are that these 52 cases placed under any circumstances might very well have been among the large number of measles cases in which no complications develop.

Furthermore, it is not unlikely that any complication of measles may be modified by a streptococcus secondarily when about 85 per cent of the cases show S. hemolyticus in the throat. The complications in the cases of Alexander and Levy appear to have been caused in large part by streptococcus, but a complete bacteriologic study of them is not recorded. Complications among streptococcus “carriers” are not identical with complications due to the streptococcus, and it is desirable to know what percentage of complications actually due to hemolytic streptococci occurred among the 85 per cent of patients with measles who carried hemolytic streptococci.

Summary.—No hemolytic streptococcus complications occurred in 112 cases of measles observed at Ft. Riley, among which streptococcus “carriers” rose from 2.6 per cent on admission to 24.1 per cent before discharge from the hospital. The percentage of “carriers” of hemolytic streptococci among normal men in the camp supplying these cases was about 25.5 per cent.

The influenza epidemic and a small epidemic of measles occurred in part simultaneously at Camp Pike during September and October, 1918. The complications following measles at Camp Pike were to a considerable extent dependent upon the combined effects of influenza and measles.

Thirty-five per cent of the measles patients showed throat cultures positive for B. influenzæ on admission to the hospital. On repeated cultures, this rose to 84 per cent before discharge.

Ward separation of cases of measles carrying hemolytic streptococci in their throats and cases not carrying these organisms were practiced in handling this epidemic. Of 867 cases of measles treated in this manner, 37 were positive for hemolytic streptococci on admission, and 205 developed positive throat cultures for these organisms during their period of observation in the hospital.

At Camp Pike, the percentage incidence of S. hemolyticus “carriers,” on admission to the measles wards, was 4.2 per cent. In cases recultured after one week, it was 10.9 per cent; after two weeks 22.8 per cent; after three weeks 26.2 per cent; and after four weeks 33.1 per cent. The weekly development of “carriers” in the “clean” treatment wards was during the first week 9.1 per cent; during the second week 17.4 per cent; during the third week 17.4 per cent; and during the fourth week 17.4 per cent.

The principal complications of these 867 cases of measles at Camp Pike were: pneumonia, 56 cases; otitis media, 48 cases, with subsequent mastoiditis in 23 cases, 2 of which had extensions to the meninges and brain. The greater part of the pneumonia occurred early in the period of observation, while most of the otitis media occurred later. Incidence of hemolytic streptococci was low during the pneumonia period and high during the prevalence of otitis media.

Hemolytic streptococci complicated 9 of these pneumonias; caused a large percentage of otitis (bacteriology incomplete), and 21 of the 23 cases of mastoiditis.

The bacteriology of 35 of the 56 pneumonias showed: Pneumococcus Type II atypical, in 36 per cent, Type IV in 22.9 per cent, Type I in 2.8 per cent and Type III in 2.8 per cent; hemolytic streptococci in 22.4 per cent; and B. influenzæ in 88.6 per cent.

The culturing of wards as units revealed widespread contact dissemination of hemolytic streptococci, at times 25 to 50 per cent of the patients in a ward becoming “carriers” within the period of a week. Streptococcus pneumonias, otitis media and its complications were furnished in large part by wards in which active dissemination occurred.

Streptococcus complications did not occur among 37 patients who were “carriers” of hemolytic streptococci when admitted to the hospital.

The epidemic dissemination of hemolytic streptococci occurs in measles wards, and is a serious danger. Many, patients whose throats become infected, develop no symptoms. In some instances streptococcus invades, and renders much more serious lesions caused by other microorganisms.

Methods to prevent transfer of infection within the ward and separation of “carriers” from “noncarriers” in different wards are efficient in keeping epidemic dissemination of hemolytic streptococci under control. Frequent throat cultures and prompt report of the results of cultures are essential.

The dissemination of B. influenzæ in patients with measles was not controlled by segregation of “carriers” and “noncarriers” of this organism as identified by throat cultures in separate wards.