This report is based upon our experience with sixty cases, seen for the most part in the last two years. The comparatively large number of cases observed during so brief a period appears to indicate that abscess of the lung is a more common condition than is generally believed. A study of the literature indicates the existence of considerable confusion in the reports on various suppurative lung conditions. There would appear to be need for greater accuracy in differentiating between acute pulmonary abscess, chronic pulmonary abscess, so-called gangrenous abscess and pulmonary gangrene, bronchiectatic abscess and bronchiectasis. The differential diagnosis is not always easy, as our best means of arriving at this is the roentgen ray, and the pictures presented by acute abscesses and acute exacerbations engrafted on chronic underlying lesions may be quite similar. The histories in many cases may lead us to suspect the existence of a chronic etiologic