If the hemorrhage is suppressed artificially, either by ligature, or by otherwise well-applied pressure, no external coagulum is formed; there appears only the internal bloody coagulum, the lymphatic effusion, and consolidation of the compressed part. The natural contraction and retraction cannot occur in vessels partially divided; hemorrhage, therefore, is more violent and dangerous from a partial than from a complete section. Again, transverse wounds are more dangerous than longitudinal; in the latter, the edges of the wound are spontaneously approximated on account of the structure of the vessels, whilst, from the same cause, the margins of the latter continue separate, and, in fact, the aperture is a complete circle; the lips of an oblique wound will be more or less apart, in proportion as it approaches to the transverse direction. When an artery has been punctured, the wound in the sheath perhaps does not correspond with that in the vessel; blood, therefore, accumulates between the vessel and its sheath, and there coagulates. The wound is thus compressed, its edges kept in contact, and the farther escape of blood prevented; the lips of the incision are then agglutinated by effused lymph, and cicatrisation occurs. This, however, cannot be expected to take place unless methodical pressure has been applied from the first. Even from small punctures blood is effused under the sheath and into the neighbouring cellular tissue, rapidly, and in such quantity as to prevent adhesion. The effusion continues, and a false aneurism is formed. If a considerable part of the circumference has been divided, the lymph may be, and generally is, superabundant, and often to such an extent as to close up the canal of the artery at that point; but, if the aperture is minute and in a longitudinal direction, lymph will seldom be effused in greater quantity than is sufficient for the cicatrisation; and, though it should be superabundant, it is afterwards removed by the absorbents. In all cases, the cellular tissue round the wounded point is much thickened and condensed by the deposition of lymph, but this gradually disappears after cicatrisation has been completed. Sometimes, and generally when the wound has been transverse and large, the process of adhesion is disturbed, and suppuration occurs; in this case the wound in the vessel communicates with the fistulous track in the externally effused lymph, and may be the source of troublesome hemorrhage. In other instances of extensive transverse wounds, the undivided slip ulcerates, and the artery becomes obliterated, by means of the same natural processes that occur in complete division. In cases of laceration of an artery, when its coats have been forcibly torn rather than divided, little or no bleeding takes place. The vessel retracts; the lacerated margins of its inner coat become puckered up, so as to contract greatly the orifice of the vessel; the lacerated sheath is