Widespread necrosis of tissue is not infrequently a conspicuous feature of this pyogenic pneumonia (Fig. 8). Upon a cloudy gray background of consolidation are numerous opaque yellowish gray or yellow patches, occasionally 2 or 3 cm. across, giving a mottled character to the cut surface. Upon the pleura these necrotic patches appear as dull opaque yellow spots. They may be surrounded by a zone of hemorrhage. The opaque material is at first firm but may undergo softening, becoming semisolid and finally purulent. Necrotic patches may be scattered throughout a lobe, but fully formed abscesses are with few exceptions immediately below the pleura (Fig. 9). [Illustration: Fig. 8.—Streptococcus pneumonia with massive necrosis. Autopsy 354. ] [Illustration: Fig. 9.—Abscess below pleura with perforation caused by hemolytic streptococci. Healing suppurative interstitial pneumonia indicated by yellowish gray lines marking interlobular septa at base of lower lobe. Autopsy 474; right lung. (See left lung, Fig. 10.) ] The duration of illness in cases of pneumonia with abscess varied from a week or less (11 instances) to more than four weeks. The duration of the greater number of cases (17 instances) was between one and two weeks. In one instance onset occurred with symptoms of influenza, pneumonia was recognized two days later, and death occurred only four days after the onset of illness. When the duration of the illness was less than a week the symptoms of onset were in some instances those of pneumonia. Table XLV shows the incidence of pneumococcus, S. hemolyticus, staphylococcus and B. influenzæ in instances of suppurative pneumonia with abscess formation, 4 instances of abscess with interstitial suppurative pneumonia being excluded: TABLE XLV ════════╤════════╤═════════════════╤═════════════════ │ NO. OF │ │ HEMOLYTIC │CULTURES│ PNEUMOCOCCI │ STREPTOCOCCI ────────┼────────┼────────┬────────┼────────┬──────── │ │ NO. │PER CENT│ NO. │PER CENT │ │POSITIVE│POSITIVE│POSITIVE│POSITIVE ────────┼────────┼────────┼────────┼────────┼──────── Bronchus│ 24│ 5│ 20.8│ 22│ 91.6 Lung │ 36│ 9│ 25.0│ 30│ 83.3 Blood │ 37│ 6│ 16.2│ 31│ 83.8 ────────┴────────┴────────┴────────┴────────┴──────── ════════╤═════════════════╤═════════════════ │ │ │ STAPHYLOCOCCI │ B. INFLUENZÆ ────────┼────────┬────────┼────────┬──────── │ NO. │PER CENT│ NO. │PER CENT │POSITIVE│POSITIVE│POSITIVE│POSITIVE ────────┼────────┼────────┼────────┼──────── Bronchus│ 12│ 50.0│ 18│ 75.0 Lung │ 14│ 35.6│ 8│ 22.2 Blood │ │ │ │ ────────┴────────┴────────┴────────┴────────