It is convenient in this introduction to give a brief account of the manner in which the material upon which the present essay is founded was obtained, and as to how far the conclusions arrived at are supported by facts. Fig. 2. — Bullet injuries. (a) Perforation of anterior tibial artery. (b) Lateral wound of brachial artery, vein divided. (6) Lateral wound of brachial artery and vein. Brentano. The small number of reports dealing with the primary treatment of arterial wounds have been furnished to me by the kindness of surgeons working at casualty clearing stations. They would have been much more comprehensive had it not been for the unfortunate accident that a large number went astray during the change which took place in the British line in March, 1918. None the less I owe a debt of gratitude to the officers who gathered the information, and to lieut.-colonel T. R. Elliott and the Medical Research Committee, who provided the necessary forms and organized their collection.