Abstract
According to the histopathological changes of autopsy, certain kinds of catarrhal changes could frequently be found at restricted areas in lung tissues of conventional guinea pigs. When the essential changes caused by inhalation of sulfur dioxide (SO2) gas were considered, it was usually difficult to distinguish them from unknown conventionally-occured changes. However, when the experiments were done using germfree guinea pigs, all data obtained from the experiments were quite free from such a disturbance.
Sulfur dioxide gas of relatively low concentration was found to act on the lungs of germfree guinea pigs as follows: In the early stage, marked congestion and hemorrhage occurred in the lung tissues. In the later stage, diffuse or nodular thickening of the alveolar septa appeared markedly. Nodular changes were due to the proliferation of argentaffin fibers.
