A BACTERIOLOGICAL AND CLINICAL STUDY OF THE NONTUBERCULOUS INFECTIONS OF THE RESPIRATORY TRACT, WITH SPECIAL REFERENCE TO SPUTUM CULTURES AS A MEANS OF DIAGNOSIS
The present series of papers dealing with infections of the respiratory tract is not so much the product of a set problem, as an evolution of some work started four or five years ago. At that time, during an investigation to determine the comparative virulence of the pneumococcus in the sputum of lobar pneumonia at various stages of the disease, with special reference to crisis,1it became necessary to isolate the strains of pneumococci used, by means of sputum cultures on blood agar plates. I was then impressed with the ease with which this method could be used as a means of diagnosis in pulmonary infections other than pneumonia. The first case under observation was that of a woman with acute bronchitis who had no previous history of cough or any disease pointing to an infection of the chest. The expectoration was typical, green, mucoid, and