The point of the hook guarded by the finger should be cautiously introduced up the vagina, and passed into the cranial cavity; having fixed it, as above directed, the finger should be applied externally, so as to correspond with the hook inside: by so doing, if the point slips or tears through the bone, the finger is ready to protect the soft parts from it; the operator is equally safe from injury, for, by grasping the shank of the hook with his thumb and other fingers, his whole hand moves with it and gives him instant warning of its going to slip. Where the deformity of the pelvis is very great, it may be necessary to break down the bones of the head still farther, in order to produce greater comminution; but even here, so long as the bones collapse well together, it will be better not to displace them from their attachments, the whole mass will come down better and with less chance of injuring the soft parts. Where, however, this is admissible, we must give the head sufficient time to undergo that process of softening which is one of the early stages of putrefaction; the cranial parietes may be gradually removed, one after the other, until we have nothing remaining but the base of the skull and the face. Dr. Burns recommends us now to convert it into a face presentation with the root of the nose directed to the pubes: "I have carefully measured, (says he,) these parts placed in different ways, and entirely agree with Dr. Hull, a practitioner of great judgment and ability, that the smallest diameter offered, is that which extends from the root of the nose to the chin." _Embryulcia._ This is merely a degree farther than the perforation: it consists in evacuating the chest and abdomen of their contents, and thus enabling their parietes to collapse. It is chiefly had recourse to in cases of deformed pelvis, where the arm or shoulder has presented, or where the distortion is so great as to prevent the trunk from passing without its bulk being lessened. Dr. Smellie's perforator with its scissor edges is best suited for this object. Having made an opening into the most presenting part of the thorax, we enlarge it by cutting away portions of the ribs and thoracic parietes, and removing the contents of the chest. The abdominal viscera are brought away in a similar way through a perforation in the diaphragm; and if this be not sufficient to let the trunk pass, the crotchet must be inserted into the brim of the child's pelvis, which must be brought down doubled upon the spine, somewhat like the process of spontaneous expulsion.