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The radiographs of only 299 of the 312 patients with a clinical diagnosis of chronic bronchitis surveyed by Medvei and Oswald (on page 1) were available for review. Thirteen unselected cases are missing, which accounts for certain small differences in the figures from those given by these authors. The patients were divided into three groups on the basis of the radiographic appearances.
Simon et al. (Thu,) studied this question.