Little or nothing can be done in cases of compressed brain from extravasation. We possess no means of preventing the effusion, and though we did, the mischief has generally taken place before the patient can receive assistance. Again, the site of the extravasation can seldom be ascertained; and, should that objection to the propriety of surgical interference not exist, still the coagulated blood cannot be evacuated even after extensive removal of the bone. If the coagulum is small, it may be gradually and wholly absorbed, or the brain may become accustomed to the pressure of what remains. It is the surgeon’s duty to take means for averting inflammatory action, and to subdue or moderate it when it has been excited. The symptoms arising from displaced bone may be relieved by surgical operation; but we must premise some observations on fracture, before speaking of the treatment necessary in such cases. FRACTURES OF THE CRANIAL BONES. At an early period of life the bones are soft and elastic; they yield readily under external violence, and it requires a great and direct force to produce fracture of them. Late in life, when the diploe disappears, the external and internal tables come in contact; the bone is brittle, and solution of continuity in it is easily effected. And it is wisely so arranged, for thus in the recklessness of childhood and youth, severe blows on the cranium, which are then of so frequent occurrence, are seldom attended or followed with danger; whilst the aged are taught by experience to avoid the unfortunate consequences so apt to result from even a slight blow on the then brittle cranium, by cautiously preserving themselves from exposure to violence. Solutions of continuity in the cranium, caused by external force, are either attended with depression or not. Fissures, mere capillary rents in the bone, may take place at the part of the cranium which is struck, or on the side opposite to that to which the force is applied. They will be found either short and limited by sutures, or extending in different directions through several sutures, as from the vertex to the base of the skull, and terminating perhaps in the foramen magnum. Fissures in the upper part of the cranium are of themselves attended with comparatively little danger; they produce of themselves no claim to attention, and really require none. But the force which gave rise to the injury of the bone may have disturbed the internal parts; and though the patient may have recovered from the first shock and the immediate effects of the violence, severe and dangerous consequences often result, and at a late period from the infliction of the injury.