In the recent epidemic of influenza and bronchopneumonia, among the S. A. T. C. at the Iowa State University, there were about 1,100 cases with thirty-three fatalities. Of these, twenty came to necropsy.
One of the most striking and constantly present postmortem findings in these cases was a marked vesicular and interstitial emphysema. The vesicular emphysema was mainly marginal, but large emphysematous bullae were quite frequently observed subpleurally. The apices of both lungs, especially the upper lobes, were involved. In many cases superficial distended air vesicles ruptured and allowed an escape of air subpleurally, giving the lung a beaded appearance. The roots of the lungs were also quite commonly involved.
The interstitial emphysema involved mainly the anterior and posterior mediastinum, the layers of the pericardium and pericardial fat, the retroperitoneal and especially the perirenal tissues. The absence of inflammation and our inability to find organisms in stained preparations of these
KELMAN SR. EXPERIMENTAL EMPHYSEMA. Arch Intern Med (Chic). 1919;24(3):332-346. doi:10.1001/archinte.1919.00090260087007