Direct incision of the sac is suitable, and the best method of treatment for aneurisms in the calf, forearm, and probably arm. Several cases in the two former situations were successfully treated by this method. On the other hand, the only case I saw in which a proximal ligature had been applied for an arterio-venous aneurism of the leg resulted most unsatisfactorily. The sac in the calf suppurated at a later date, and for many weeks the escape of small quantities of blood from the remaining sinus kept up the fear of a severe attack of secondary haemorrhage until the sinus closed. In the case of femoral and popliteal aneurisms the method of Antyllus is often unsuitable. A case of arterio-venous aneurism of the femoral artery quoted in the _Lancet_[17] will illustrate the difficulty which may be met with in determining the actual bleeding point in the irregular cavity laid open. In any case the necessary ligature of both artery and vein is a serious objection to the direct method either in the thigh or ham, and more particularly if adopted before the damage dependent on the dissection of the limb by extravasated blood has been repaired. Proximal ligature (Hunterian) even, offers dangers under these circumstances. In one case with which I became acquainted, it was followed by gangrene, necessitating amputation. The lesion in this instance was a perforating one of the femoral artery and vein. For either femoral or popliteal arterio-venous aneurisms ligature of the artery above and below the aneurism is the best and safest treatment. In view of the healthy state of the vascular wall in most of these cases, the advantage of placing the ligatures as near to the wounded spot as can be managed without interference with the sac is afforded. A number of popliteal cases treated in this way did perfectly. In the femoral cases a considerable period of rest to allow of consolidation of the sac, and readjustment of the circulation, should always be allowed to elapse. In the case of popliteal arterio-venous aneurisms a number were successfully treated by proximal (Hunterian) ligature, and by single ligature immediately above the sac. In a considerable proportion of the latter both artery and vein were tied. This was apparently the result of the difficulty of isolating the vessels in the tangled mass of clot and cicatricial tissue surrounding them, and is a strong argument against too early interference. The late Sir William Stokes expressed himself as in favour of ligature of the artery in Hunter's canal, combined with that of the great anastomotic branch, and quoted some successful cases to me. I have grave doubts, however, whether the varix can often be permanently cured by this operation. I can give no useful statistics on this subject, but with regard to the popliteal aneurisms I may state that in three instances gangrene of the leg followed early operative interference in the popliteal space.