The alveolar septums are thickened because of the extravasations of blood. The normal circulation in the lung is hindered and in the extra-uterine life there appears a stasis, which hinders the taking up of air and predisposes secondarily to atelectasis. Following stasis and bacterial changes, there may appear in the lungs of prematures a high grade, almost total, inhibition of the circulation of the blood. Inflammatory changes in the lungs or bronchi appear infrequently and atypically in the first days of life. Bronchopneumonia, after the second week of life, begins to play an important part in causing death.
Epicardial hemorrhages are of common occurrence.
They appear just as do the subpleural hemorrhages and those in all the other organs. Subcapsular liver hemorrhages are on a par with other subserous hemorrhages. They are important only insofar as they may be extensive, and with rupture of the capsule may result in hemorrhage into the peritoneal cavity with death. Hemorrhages into the kidney are frequent. In the interstices of the apices of the pyramids, or in the neighborhood of the venae et arteriae arciformes.