The bacteriology and pathology of bronchopneumonia during the last two months (December and January) have become quite different, at the Chelsea Naval Hospital, from that found during the preceding three months, including the most severe period of the first local outbreak of influenza. In the earlier period, cultures of Pfeiffer's bacillus were obtained from the lungs in 86 per cent. of cases postmortem, the organism often being found in pure culture, pneumococci in 50 per cent., and hemolytic streptococci in 13 per cent.; while during the last two months, cultures of hemolytic streptococci have been obtained from the lungs in 100 per cent, of those examined at necropsy, and in the majority of instances pure cultures were obtained. Pfeiffer's bacillus was demonstrated in only two cases of a total of sixteen, and these two were examined the first week of December.
This marked variation in the type of invading organism