The Types of Pneumococci in Tuberculous Sputum

The success of Cole 1 and his associates 2 in establishing four groups among the pneumococci affords a new basis for the study of the transmissibility and pathology of acute lobar pneumonia. The most important result of this work is, perhaps, its bearing on the epidemiology of the disease. It has been generally accepted that the pneumococci of the normal mouth may, under favorable conditions, become implanted in the lung and are there able to set up the condition known as lobar pneumonia. The work of Rosenow 3 has been considered as favoring this theory by supposing that the pneumococci of the mouth, under changed environmental conditions, undergo a mutation into a virulent type. On the other hand, the work indicating that different types of pneumococci may operate in producing pneumonia, raises the question as to whether pneumonia may not be a transmissible or epidemic disease caused by distinct, virulent types of this organism, passed from individual to individual. To prove the first theory, it must be shown either that the organism of acute pneumonia and that ordinarily present in the healthy mouth are the same, or, postulating a mutation, that the comparatively avirulent mouth strain, as a result of the changed lung condition, assumes the characteristics of one of the virulent groups associated with the acute disease. It was with this problem in mind that the present work was undertaken. In pulmonary tuberculosis and the other lung conditions