During the past decade, a rather extensive literature has accumulated on the surgery of the phrenic nerve as applied to pulmonary tuberculosis, bronchiectasis and abscess of the lungs. This literature has become increasingly voluminous, particularly in the last four or five years. Most of the authors have dealt with the subject: (1) purely from the academic standpoint, (2) by reporting series of cases varying in number from 1 to 600, or (3) by combining both of the foregoing methods of approach. The technic of phrenicectomy and exaresis has been adequately described many times, and as a result the procedure, with minor individual variations, has become standardized. The accidents to be avoided and cautions against them have almost all been directed toward errors in technic and how to avoid them, and also to the possibility of grave and unavoidable mediastinal hemorrhage.
Among the technical errors that have occurred, even with experienced