It is recognized by most of the modern investigators that little reliance can be put on the finding of B. influenzæ-like bacilli in direct smears. The organism is markedly pleomorphic, occurring as extremely small coccoid forms up to threads of various lengths. Notwithstanding these morphological variations the organisms are usually seen as tiny bacilli, and these are considered as the typical form. We carried out a series of microscopical examinations of carefully made smears from the throats of patients with influenza. Particular attention was given to the occurrence of organisms resembling in morphology and staining B. influenzæ, pneumococci and M. catarrhalis. We have divided the cases roughly into three types—early, serious, and convalescent. Table II shows our results. The term B. influenzæ-like was used for the typical morphological picture so often described. Dr. Frost and Mr. Scott carried out this portion of our work and their results are interesting. Blood cultures were done on 22 cases. Pneumococcus mucosus was grown from one patient who three days later came to autopsy (Case 767). In another case pneumococcus-like organisms were seen in smears from the dextrose broth flask after 24 hours’ incubation. These, for some unknown reason, did not grow on blood agar plates. After 48 hours smears made on blood agar from the original flask gave a growth of B. influenzæ and a M. catarrhalis-like organism. I consider this result a very unsatisfactory one, being quite unable to explain the failure to grow the pneumococci-like forms on transfer. Possibly the acidity developed might account for it. TABLE III AGGLUTINATION TESTS WITH SERA OF CONVALESCENT INFLUENZA PATIENTS ═══════════════════════════╤═══════════╤═══════════╤═══════════ DILUTION OF SERUM │ + │ +– │ – ───────────────┬───────────┼───────────┼───────────┼─────────── Convalescents │1-1 │ 3│ 0│ 2 │1-10 │ 5│ 2│ 7 │1-40 │ 2│ 3│ 9 │1-80 │ 0│ 1│ 13 │1-160 │ 0│ 0│ 14 ───────────────┼───────────┼───────────┼───────────┼─────────── Normal Controls│1-10 │ 1│ 2│ 0 │1-40 │ 0│ 1│ 2 ───────────────┴───────────┴───────────┴───────────┴─────────── The complete agglutination as would be indicated by +++ or ++ was not seen.