The forceps is also occasionally required in presentations of the face and nates. In the first case we must pass up the blades on each side of the face, and along the side of the head, having previously ascertained to which side of the pelvis the chin is turned. In nates cases, the blades should also be passed up along the sides of the child's pelvis, and here the advantages of a broad fenestra will be very evident, for otherwise our hold will not be firm enough without exerting an improper degree of pressure. Cases every now and then occur, where from convulsions, &c., it is desirable to apply the forceps whilst the patient is lying upon her back, as is practised upon the continent. "The patient is placed across the bed, propped up in a half-sitting posture, by pillows, &c., her pelvis resting upon the edge, her feet on two chairs, the knees supported by assistants. Two, and generally three fingers are passed, if possible, up to the os uteri, on the side where the blade is to be introduced: the index finger, is held a little behind the middle finger, so that this last, by projecting somewhat, forms a species of ledge upon which the blade slides, and which acts as a fulcrum to it. The handle is held at first nearly perpendicular; but as the blade advances, it gradually approaches the horizontal direction, being guided by the pelvic curve of the instrument. The middle finger, along the ulnar surface of which the convex edge of the blade slides, prevents its extremity from passing too far backwards, and directs it in the axis of the pelvis. When introduced to the full extent, the handle is inclined obliquely downwards, and is now grasped by an assistant passing his hand below the patient's thigh. The other blade is introduced in the same way on the opposite side of the pelvis; and the locking, extraction, &c., conducted much in the same manner as in England." (_British and Foreign Med. Rev._ vol. iii. April 1837, p. 419.)