Pericarditis.—Among 241 autopsies on individuals with pneumonia following influenza, pericarditis occurred 23 times; these lesions were classified as follows: Serous pericarditis, 1; serofibrinous pericarditis, 9; seropurulent pericarditis, 1; fibrinopurulent pericarditis, 10; purulent pericarditis, 2.

It is noteworthy that in 12 of 23 instances of pericarditis the lesion was associated with S. hemolyticus infection of the lung and whenever in these instances cultures were made (Autopsies 434, 485, 499 and 504) hemolytic streptococci were obtained from the pericardial exudate in pure culture.

The tendency of interstitial suppurative pneumonia to produce pericarditis is especially evident. Among 21 instances of interstitial suppurative pneumonia pericarditis occurred 6 times (28.6 per cent); among 39 instances of suppurative pneumonia with abscess formation, pericarditis occurred twice (5.1 per cent); whereas among all other autopsies, namely, 181, the lesion occurred 15 times (8.3 per cent).

Pericarditis occurred in association with pneumonia referable to Pneumococcus I, once, (Pneumococcus I isolated from the pericardium); to Pneumococcus II, once; to atypical Pneumococcus II, 5 times (twice isolated from the pericardium); and to Pneumococcus IV, twice (once isolated from the pericardium).

Peritonitis.—Purulent peritonitis occurred only twice, in both instances in association with pneumonia caused by hemolytic streptococci. Purulent peritonitis was part of a general serositis involving both pleural cavities, pericardium and peritoneum in 2 noteworthy instances:

Autopsy 465.—J. K., white, aged twenty-two, farmer from Oklahoma, had been in military service one month. He was admitted to the hospital with influenza, sore throat and bronchitis twenty-four days before his death. Signs of pneumonia were recognized thirteen days later and at the same time there was otitis media on the right side. Empyema and pericarditis were found three days before death and two days later 1000 c.c. of cloudy fluid were withdrawn from the chest.

Anatomic Diagnosis.—Suppurative pneumonia with consolidation and abscess in right lower lobe below pleura; purulent pleurisy on right, seropurulent pleurisy on left side; beginning serofibrinous pericarditis; fibrinopurulent peritonitis; purulent bronchitis.

The body is emaciated. The right pleural cavity contains 350 c.c. of thick, creamy yellow pus in which are flakes of fibrin; the right lung is collapsed and lies at the back and inner side of the cavity. The left pleural cavity contains 500 c.c. of turbid, yellow, seropurulent fluid in which is soft fibrin. The lower lobe of the right lung is consolidated throughout, flabby, gray red and finely granular on section. Below the pleura of the posterior border is a wedge-shaped cavity with its base 1.5 cm. across, in contact with the pleural surface. About the cavity consolidated tissue has an opaque, yellow color. Bronchi in both lungs contain mucopurulent fluid. The pericardial cavity contains 20 c.c. of turbid fluid; the left auricular appendage is bound by a thin layer of fibrin to the parietal pericardium.

The peritoneal cavity contains 100 c.c. of thick, creamy, yellow, purulent fluid. Between the diaphragm and liver is a layer of fibrin, in places 1.5 cm. in thickness; fibrin is present upon the peritoneum overlying the kidneys and base of mesentery.

Bacteriologic examination shows the presence of hemolytic streptococci, obtained in pure culture from the blood of the heart, right pleural cavity and peritoneum. From the right bronchus are grown S. hemolyticus, B. influenzæ and a few colonies of S. viridans and staphylococcus.