THE PAST decade has witnessed rather definite changes in the content of thoracic surgery. An ever-increasing employment of antibiotic drugs in the management of acute respiratory tract infections has decreased sharply the incidence of pneumonia, postpneumonic empyema, and pulmonary abscess, at least as seen in general hospital practice. The latter two diseases at one time furnished a considerable fraction of thoracic surgical case material, especially in the winter months, but are now reduced to a minor role. Despite this and other results of chemotherapy, the field of thoracic surgery continues to expand. Almost every year brings its new surgical procedure or new therapeutic concepts. By way of illustration one has only to recall the enormous progress made in the area of cardiovascular surgery since the first successful ligation of a patent ductus arteriosus was performed in 1938.
One development in thoracic surgery which has contributed in a minor way to