Pulmonary Hypersensitivity Disease Due to Inhaled Organic Antigens

due to the inhalation of organic dusts are not well understood. Some light may be thrown on these problems by the findings in pulmonary aspergillosis and farmer's lung, which provide comprehensive examples of hypersensitivity diseases of the lungs due to inhaled organic antigens. These somewhat unfamiliar diseases and their various forms are not always clearly distinguished from each other. They encompass, between them, reactions occurring in the bronchi, in and around the bronchi, and in the peripheral gas-exchanging tissues of the lungs, usually called, for lack of a more precise term, the interstitial tissues. These reactions in different parts of the respiratory tract have their own particular clinical and other features, and it is now