From the foregoing studies of the bacteriology of peribronchiolar and hemorrhagic peribronchiolar pneumonia the following conclusions may be drawn: (_a_) B. influenzæ is found in most instances of these lesions in the bronchi and in about half of all instances in the lungs, but does not occur unaccompanied by other microorganisms. (_b_) In a considerable number of autopsies pneumococcus is the only microorganism that accompanies B. influenzæ; from the lungs it penetrates into the blood from which it is obtained in pure culture. (_c_) In a considerable number of instances S. hemolyticus accompanies B. influenzæ, and in some of these instances (representing a large proportion of the relatively small number of cases examined during life), examination of the sputum has demonstrated that infection has been secondary to a pneumonia with which no hemolytic streptococci have been found in the sputum. =Lobular Consolidation.=—Consolidation of scattered lobules or groups of lobules has occurred in nearly all instances, namely, 71 of 80 autopsies with bronchopneumonia unaccompanied by lobar pneumonia or by suppuration. When death follows shortly after the onset of pneumonia, patches of consolidation have a dull deep red color; blood-tinged fluid escapes from the cut surface which is almost homogeneous or finely granular. The consolidated tissue seen through the pleura, which is raised above the general level, has a bluish red color. Isolated lobules or groups of lobules which have undergone consolidation may be scattered throughout the lungs, but not infrequently there is confluent consolidation of the greater part of lobes, of whole lobes or of almost an entire lung. Such lungs are very heavy and may weigh 1,400 or 1,500 grams; bloody serous fluid exudes from the cut surface. The lesion resembles the red hepatization of lobar pneumonia, but confluent patches of pneumonia are usually well defined by lobule boundaries. The tissue is soft and the granulation of lobar pneumonia is absent. In many instances the lobular or confluent areas of consolidation are reddish gray; in some instances consolidated tissue is in places red and elsewhere gray, and in a smaller group of autopsies there is gray consolidation only (Fig. 6). Red lobular consolidation is often seen in those who have died within the first four days following the onset of pneumonia, but is almost equally frequent after from five to ten days; the average duration of pneumonia in these cases was 5.5 days. Combined red and gray consolidation was more frequently found when pneumonia had lasted more than five days, the average duration of pneumonia being 7.3 days. The greater number of instances of gray consolidation were found after seven days of pneumonia, the average duration of the disease being 10.0 days. These figures are cited to show that lobular, like lobar, consolidation passes gradually from a stage of red to gray hepatization, but the change occurs more slowly and is often long delayed.