It has, however, special elements of danger in it, involved in the unavoidable division, of part at least, or probably the whole, of the scalenus anticus. The phrenic nerve, from its position on that muscle, requires special care to avoid dividing it, and in most cases the internal jugular vein is also in the way. The branches of the thyroid axis, which cross the neck, are quite in the line of the incision. The lowest cord of the brachial plexus lies immediately behind the artery, between it and the middle scalenus. The pleura lies just below it. The subclavian vein is generally quite safe, running in front of the scalenus anticus, and at a lower level. The presence of the superior intercostal branch adds greatly to the danger of ligature of the vessel in this position, from its interfering with a proper clot. _Results._--Dupuytren[17] performed it successfully for a traumatic axillary aneurism. Auchincloss[18] did it for a large true aneurism, but the patient died sixty-eight and a half hours after the operation. Liston cut through the outer portion of the scalenus with success for an idiopathic aneurism. Thirteen have been collected by Wyeth with four recoveries and nine deaths. LIGATURE OF SUBCLAVIAN.--_Third Part._--For this comparatively common operation, various methods of procedure have been suggested and employed. In the dead body, where the axilla is free from swelling, and in thin patients, the artery in this third stage is tolerably superficial, and can be secured with ease. But in very muscular men, with short necks and well curved clavicles, and specially when the axilla is filled up with an aneurism, and the shoulder cannot be depressed, the operation becomes very difficult. _Operation of Ramsden, Liston, and Syme._--_Position._--The patient lying on his back with his shoulders supported by pillows, and his head lying back, and drawn to the opposite side; the shoulder of the affected side must be depressed as much as possible.