1. Most aeration disturbances are not congenital. 2. Aeration disturbances are frequently associated with pulmonary infection. 3. Aeration disturbances are not usually the causes of pulmonary infection. 4. Aeration disturbances develop during the course or as the sequelae of pulmonary infection. 5. Aeration disturbances may spontaneously disappear. 6. Treatment of aeration disturbances must be conservative and surgical treatment should not be considered until a clinical cause and effect relationship between the aeration disturbances, the symptoms and the supposed benefits of surgical treatment are fulfilled.