TABLE L ═══════════════════╤═════════╤════════════════╤═══════════╤════════════ │ LOBAR │BRONCHOPNEUMONIA│SUPPURATIVE│INTERSTITIAL │PNEUMONIA│ │ PNEUMONIA │SUPPURATIVE │ │ │ WITH │ PNEUMONIA │ │ │ ABSCESS │ ───────────────────┼────┬────┼────────┬───────┼─────┬─────┼──────┬───── „ │No. │ % │ No. │ % │ No. │ % │ No. │ % ───────────────────┼────┼────┼────────┼───────┼─────┼─────┼──────┼───── No pleurisy noted │ 30│46.9│ 44│ 55│ 1│ 2.6│ 1│ 5.9 Serous pleurisy │ 5│ 7.8│ 9│ 11.2│ │ │ │ Fibrinous pleurisy │ 10│15.6│ 5│ 6.2│ 1│ 2.6│ │ Serofibrinous │ 12│18.2│ 14│ 17.5│ 3│ 7.7│ │ pleurisy │ │ │ │ │ │ │ │ Seropurulent │ │ │ │ │ 9│ 23.1│ 1│ 5.9 pleurisy │ │ │ │ │ │ │ │ Fibrinopurulent │ 7│10.9│ 5│ 6.2│ 17│ 43.6│ 12│ 70.6 pleurisy │ │ │ │ │ │ │ │ Purulent pleurisy │ │ │ 3│ 3.7│ 8│ 20.5│ 3│ 17.6 ───────────────────┼────┼────┼────────┼───────┼─────┼─────┼──────┼───── Total │ 64│ │ 80│ │ 39│ │ 17│ ───────────────────┴────┴────┴────────┴───────┴─────┴─────┴──────┴───── Empyema has occurred, on the one hand, in 12.4 per cent of instances of lobar pneumonia and in 9.9 per cent of instances of bronchopneumonia alone. It has occurred, on the other hand, in 87.2 per cent of instances of suppurative pneumonia with abscess formation and in 94.1 per cent instances of interstitial suppurative pneumonia. These suppurative lesions are caused by hemolytic streptococci, and when cultures are made from the pleural exudate this microorganism is isolated. Of 16 instances in which empyema has occurred in association with lobar pneumonia or bronchopneumonia unaccompanied by suppuration in 6 there has been infection with hemolytic streptococci. Empyema has occurred in the absence of hemolytic streptococci only 10 times.