In Experiment 10 a very large monkey received by intratracheal injection, made with syringe and needle, 5 c.c. salt solution suspension of Pneumococcus III and 3 strains of B. influenzæ, (2 recently isolated from cases of influenza and 1 from autopsy in a case of postinfluenzal pneumonia). The animal died twenty-four hours later.
This simultaneous introduction of B. influenzæ and Pneumococcus III in large quantity has produced rapidly fatal pneumonia with lobar distribution. Hepatization was homogeneous and red, and outside the consolidated parts of the lung there was hemorrhage and edema. The lesion resembled that found when death has occurred within a few days after the onset of pneumonia following influenza, but had no distinctive characters establishing its relation to pneumonia following influenzæ.
In Experiment 11 Pneumococcus III alone in small amount was introduced into the trachea of a small monkey. The animal was very sick, but its condition improved and recovery seemed probable. The animal was killed seven days after inoculation, and typical lobar pneumonia with gray hepatization was found at autopsy.
Experiment 11
November 20, 1918.—Small monkey; throat culture: negative for B. influenzæ, pneumococcus and S. hemolyticus. November 28 and December 6.—Nose and throat cultures again negative for B. influenzæ. December 9—4:30 P.M.—Intratracheal injection with syringe and needle of 0.33 c.c. of an eighteen hour broth culture of Pneumococcus Type III. December 10.—The animal is sick, huddled up in his cage with head down; there is rapid respiration with expiratory grunt and the mucous membranes are moderately cyanotic. There is frequent cough. Throat culture: Pneumococcus III present in abundance. December 15.—The animal appears to be better. Respirations are still rapid but less labored. December 16.—The animal is improving but very weak and emaciated.
Autopsy.—The pleural cavities contain no fluid. On the right side are several strands of fibrin. The right lower lobe with the exception of a small patch at the summit and the lower part of the middle lobe are voluminous, have a dull gray surface covered by a scant layer of fibrin and are firmly consolidated. On section the consolidated tissue has a gray color and is conspicuously granular, the granulation resembling, on a slightly smaller scale, that seen in human lobar pneumonia. The bronchi contain a small amount of viscid fluid.
Bacteriology.—Direct smears from the trachea and the lower lobe of the left lung contain Gram-positive diplococci. Cultures from the trachea and from the blood of the heart contain Pneumococcus III. Cultures from the left lower lobe, from the liver and from the spleen remain sterile.
Microscopical Examination.—There is abundant infiltration of the subepithelial tissue of the trachea with plasma cells. Superficial ciliated epithelium is in places lost. At one point is a small focus of hemorrhage. Alveoli in the consolidated part of the lungs contain polynuclear leucocytes and fibrin and exhibit the appearance seen in lobar pneumonia in man.
Fig. 33.—Experimental lobar pneumonia in the stage of gray hepatization produced by injection of Pneumococcus III into the trachea of a monkey (Experiment 11). The alveoli are uniformly filled with plugs of fibrinous exudate.