The bacillus of Bordet and Gengou is present in the sputum in early cases of pertussis, and in the lungs at autopsy in fatal cases of the disease. After the second week it is not present in the sputum in sufficiently large numbers to be readily isolated. The influenza bacillus is found at as early a stage of pertussis as is the Bordet-Gengou bacillus, and it persists in the sputum for a longer time. The agglutinins in the blood of pertussis patients are not more regular and not always higher for the Bordet-Gengou bacillus than for B. influenzæ. The two organisms are culturally distinct and their action on laboratory animals different. Complement deviation tests with the serum of immunized rabbits show a further difference in the immune bodies produced by the two varieties of bacilli. The negative results of the complement deviation tests with the patients' serum in this study, compared with the positive results of similar tests made by Bordet and Gengou, I am not able to account for.
This study has contributed support to the view that the Bordet-Gengou bacillus is the possible cause of pertussis, but it has not produced any distinctively new evidence of this relationship beyond the proof of the wide dissemination of the peculiar bacillus in nature and its occurrence in pertussis. A study of bronchial secretions in other acute diseases of the respiratory tract for the bacillus has not yet been extensively made and is called for. I shall hope to report on this phase of the subject at another time.