Abstract
Recurrent exposure of dogs to phosgene gas produces a chronic obliterative bronchiolitis with a characteristic physiologic picture. After an acute phase, in which changes in elastic behavior predominate, a definite increase in lower airway resistance is seen which persists throughout the period of exposure. Accompanying this change the uniformity of distribution of inspired air is progressively disturbed as evidenced by nitrogen washout curves. In addition, microscopic changes suggestive of early, peribronchiolar emphysema are seen.