18. In examining a wound, a finger should be gently introduced, if possible, in the course of the ball, to its utmost extent; in parts connected with life, or liable to be seriously injured, it is the only sound usually admissible. While this examination is taking place, the hand of the surgeon should be carefully pressed upon the part opposite where the ball may be expected to lie, by which means it may perhaps be brought within reach of the finger, and for want of which precaution, it may be missed by a very trifling distance. While the finger is in the wound the limb may be thrown as nearly as possible into that action which was about to be performed on the receipt of the injury, when the contraction of the muscles and the relative change of the parts will more readily allow the course of the ball to be followed. If this should fail, attention should be paid to the various actions of the limb, the attendant symptoms arising from parts affected, and what may be called the general anatomy of the whole circle of injury. A muscle, in the act of contraction, may oppose an obstacle to the passage of an instrument in the direction the ball has taken, especially if it should have passed between tendons or surfaces loosely connected by cellular membrane; as by the side of, or between the great blood-vessels, which by their elasticity may make way for the ball, and yet impede the progress of a sound. When the ball is ascertained to have passed beyond the reach of the finger, a blunt silver sound or elastic bougie may be used, and the opposite side of the limb should be carefully examined, and pressure made on the wounded side, when it will probably be found more or less deeply seated. If the ball should not be discoverable by these means, the surgeon should consider every symptom, and every part of anatomy connected with the wound, before he decides on leaving the ball to the operations of nature. 19. It is unnecessary to dilate a wound without a precise object in view, which might render an additional opening requisite. This dilatation or opening, when made, should always be carried through the fascia of the limb. A wound ought not to be dilated because such operation may at a more distant period become necessary. The necessity should first be seen, when the operation follows of course.