Major histopathological findings. (A) Vehicle. Within the lumina of alveoli, there are mats of pale eosinophilic finely beaded to fibrillar material (fibrin), in which are embedded moderate numbers of both viable and degenerated (karyorrhectic) neutrophils. (B) ALD. No inflammatory cells detectable within alveolar lumina. (C) AHD. Note within the lumina of slightly compressed alveoli scattered neutrophils (right lung, hematoxylin-eosin, 200×, scale bar = 100 μm).