usually accompanies mortification from constitutional causes. In a day or two more, the gangrene will frequently extend, when the limb swells, becomes painful, and more streaked or mottled in color; the swelling passes the knee, the thigh becomes œdematous, the patient more feverish and anxious, then delirious, and dies. An extreme case will best exemplify the practice to be pursued. A soldier is wounded by a musket-ball at the upper part of the middle third of the thigh, and on the third day the great toe has become of a tallowy color and has lost its life. What is to be done? Wait with the hope that the mortification will not extend. Suppose that the approaching mortification has not been observed until it has invaded the instep. What is to be done? Wait, provided there are no constitutional symptoms; but if they should present themselves, or the discoloration of the skin should appear to spread, amputation should be performed forthwith, for such cases rarely escape with life if it be not done. Where in such a case should the amputation be performed? I formerly recommended that it should be done at the part injured in the thigh. I do not now advise it to be done there at an early period, when the foot only is implicated; but immediately below the knee, at that part where, if mortification ever stops and the patient survives, it is usually arrested; for the knee is by this means saved, and the great danger attendant on an amputation at the upper third of the thigh is avoided. The upper part of the femoral artery, if divided, rarely offers a secondary hemorrhage. The lower part, thus deprived by the amputation of its reflex blood, can scarcely do so; and if it should, the bleeding may be suppressed by a compress. The blood will be dark colored. If the upper end should bleed, the blood will be arterial, and by jets, and the vessel must be secured by ligature. 29. When from some cause or other amputation has not been performed, and the mortification has stopped below the knee, it is recommended to amputate above the knee after a line of separation has formed between the dead and the living parts. This should not be done. The amputation should be performed in the dead parts, just below the line of separation, in the most cautious and gentle manner possible, the mortified parts which remain being allowed to separate by the efforts of nature. A joint will be saved, and the patient have a much better chance for life. 30. A wound of the axillary artery rarely leads to mortification of the fingers or hand. If it should do so, the principle of treatment should be similar, although the saving of the elbow is not so important as that of the knee: neither is the amputation in the axilla, below the tuberosities of the humerus, as dangerous as that above the knee. 31. Mortification after the sudden application of intense cold or heat is to be treated on similar principles.