Fractures of the base of the skull are the result of great force applied to the lateral parts of the head, to the vertex, or to the base itself through the spinal column. A blow inflicted by an obtuse body on the top of the head, whilst it is at rest and fixed—by producing expansion of the lateral parietes, and forcing the base down upon the upper part of the spinal column—may have the effect of breaking up the connections of the bones at the base, which is the weakest part of the cranium, and splintering them to a greater or less extent. Again, if a person falls from a height, he perhaps alights on some part of his trunk, as the buttocks, and this coming to a state of rest, whilst the head is still in projectile motion, the spinal column is driven towards the cavity of the cranium, and the same effects are thereby produced as in the preceding instance. Or the patient alights on his head, and the base of the cranium is then impinged upon by the weight of the whole trunk, as well as by the force of the projecting power, and in this case also the base is frequently broken up. In the sketch here given, showing extensive fracture of the occipital and sphenoid bones into the foramen magnum, the patient, a brick-layer, fell from a ladder on the vertex. He lay comatose for some days before death: there was found extensive extravasation over the middle lobes and cerebellum. Concussion has resulted from falls when the person has alighted on his nates or feet; but the symptoms attendant on fracture of the base are more generally those of compression of the brain. In this accident the bones are seldom displaced to any great extent; the dura mater is generally lacerated, its bloodvessels, and frequently its sinuses, are wounded, and blood is consequently effused at the base of the brain, where injury is most fatal. The upper part of the brain may bear pressure to a considerable degree without bad consequences ensuing, but compression at the origins of the nerves is always highly dangerous and generally fatal. Bleeding from the nose, mouth, and ears, when attended with other circumstances and symptoms evincing a violent injury and consequent cerebral disturbance, has been considered as decisive of fracture at the base having occurred. But we find that such bleeding happens in slight injuries unattended with any circumstances or consequences to induce a belief that so serious an injury has taken place: and again, in cases where dissection has shown most extensive fracture in the temporal, sphenoid, and æthmoid bones, no blood had issued from their external openings. Fracture of the base of the skull generally proves fatal, but many cases are met with in which there is reason to believe that it had taken place, and yet the patients have recovered with perhaps partial paralysis. Of this I lately met with a good example in the case of a girl seven years of age, whose head had been squeezed between a wall and the back of a cart, and thereby