Heavy suture materials, regardless of type, are not desirable. Fine silk, cotton, synthetics, or absorbable sutures should be used routinely. Every surgeon has his or her own preference for suture material, and new types are constantly being developed. Fine silk is most suitable for sutures and ligatures because it creates a minimum of tissue reaction and stays securely knotted. If a surgeon's knot is laid down and tightened, the ligature will not slip when the tension on the silk is released. A square knot then can be laid down to secure the ligature, which is cut close to the knot. The knots are set by applying tension on the ligature between a finger held beyond the knot in such a plane that the finger, the knot, and the hand are in a straight line. However, it takes long practice to set the first knot and run down the setting, or final knot, without holding the threads taut. This detail of technique is of great importance, for it is impossible to ligate under tension when handling delicate tissue or when working in the depths of a wound. When tying vessels caught in a hemostat, it is important that the side of the jaws of the hemostat away from the vessel be presented so that as little tissue as possible is included in the tie. Moreover, the hemostat should be released just as the first knot is tightened, the tie sliding down on tissue not already devitalized by the clamp. One-handed knots and rapidly thrown knots are unreliable. Each knot is of vital importance in the success of an operation that threatens the patient's life.