Abstract
1. A number of factors influencing the appearances of the radiograph in cases of chronic bronchitis and emphysema are discussed. 2. In simple uncomplicated cases of chronic bronchitis the radiographs fall into four fairly clearly defined groups. The radiological appearances of these groups are described. 3. Changes occurring in the radiograph during acute exacerbation of cases of chronic bronchitis are described. 4. The behaviour of the radiological appearances over a long period are discussed. 5. The radiological findings are described in cases of chronic bronchitis complicated by congestive cardiac failure and pulmonary arterial hypertension.