_Primary haemorrhage._--A marked distinction needs to be drawn between external and internal haemorrhage. External haemorrhage from the great vessels of the limbs, or even of the neck, proved responsible for a remarkably small proportion of the deaths on the battlefield. This statement may be made with confidence, since it is not only my own experience, but coincides with what I was able to glean from many medical officers with the Field bearer companies. It is, moreover, supported by the facts that cases in which primary ligature had been resorted to were extremely rare at the Base hospitals, while, on the other hand, traumatic aneurisms and aneurismal varices of any one of the great trunks of the neck and limbs were comparatively common. Again, primary amputation for small-calibre bullet wounds, except when complicated by severe injury to the bones, was so rare as to render more than doubtful the frequent occurrence of severe primary haemorrhage on the field. Only one case of rapid death due to bleeding from a limb artery was recounted to me. In this a wound of the first part of the axillary artery proved fatal in the twenty minutes occupied by the removal of the patient to the dressing station. The amount of haemorrhage in many instances was no doubt checked by the application of pressure at the time of the first field dressing; but it can scarcely be argued that such dressings as were applied were of sufficient firmness to control bleeding from such trunks as the brachial, femoral, or carotid arteries. The spontaneous cessation of haemorrhage is rather to be ascribed to the special method of production and the consequent nature of the wound. The lesions were the result of immense force strictly localised in its application, which might well induce very complete and rapid contraction of the vessel wall; while the track in the soft parts was not only narrow, but also lined by a thin layer of tissue possibly so devitalised superficially as to specially favour rapid coagulation of the blood. Beyond this the tracks were often sinuous when the position of the limb at the time of reception of the injury was replaced by one of rest. The influence of mere narrowness of the track is illustrated by classical experience in the development of aneurismal varices after stabs by knives or bayonets; and in the injuries under consideration the frequent development of large interstitial haemorrhages into the tissues of the limbs indicated that blood does not readily travel along the wound track. It was noteworthy that when haemorrhage did occur it was most free from, or often limited to, the wound of exit. This is due to the direction of the active current set up by the rush of the bullet through the tissues. The mechanical factor is, no doubt, the most important.