Summary.
The diffuse involvement of all the lung tissue, chiefly with a serous exudate in the subpleural, interstitial, perivascular, and peribronchial tissues, as well as in the alveoli, is associated with other elements which occur in aplastic reactions; red blood cells, fibrin, and bacteria. Added to the aplastic exudate is an acute necrosis of bronchial and alveolar epithelium involving at times the walls of these structures; consequently, the histology of this disease is almost as specific as that of any biological reaction.
(2) LOCALIZATION AND NECROTIZATION OF THE PNEUMONIC PROCESS
In the preceding description, the gross and microscopic anatomical changes in the lung have been discussed minutely. The picture presented persists, even though it becomes less intense, and forms a background upon which later variations may be superimposed. There is no justification for the opinion that the changes described are necessarily the most acute, but it is presumably correct to suppose that an aplastic, inflammatory reaction will terminate fatally more quickly than a cellular reaction (160), and upon this basis the sequential description in this narrative is arranged.
In the group of fatal cases of influenza, now to be discussed, the lesions of the pulmonary parenchyma are characterized by more definite lung consolidation. Thirty-nine examples presenting an average illness of ten days are included in the following description.
Gross Picture.
The external examination of the body includes nothing not described in the previous group.
FIG. XIX. AUTOPSY NO. 123. A SMALL AIR BUBBLE IN THE INTERSTITIAL TISSUE. COMPARE FIGURE [XVIII].
HELIOTYPE CO. BOSTON
