When the hæmorrhage takes place from the anterior branch, the clot tends to spread towards the base, and may press upon the cavernous sinus, causing congestion and protrusion of the eye, with paralysis of the oculo-motor nerve and wide dilatation of the pupil. In some cases of middle meningeal hæmorrhage there is no gross injury to the brain; the area underlying the clot is merely compressed and emptied of blood, and, on being exposed, the brain is found flattened, or even deeply indented by the blood-clot, and it does not pulsate. If the clot is removed, the brain may regain its normal contour and its pulsation return. The mortality is over 50 per cent. If the fracture is compound, the blood can escape, and therefore the pressure symptoms are less evident or may be entirely absent. It is a fact of some medico-legal importance that hæmorrhage from the middle meningeal may not take place till some days, or even weeks, after an injury, which at the time was only attended with symptoms of concussion. This condition is known as _traumatic apoplexy_. _Treatment._--Immediate operation is imperatively called for, not only to arrest the hæmorrhage and remove the clot, but also to ward off the œdema of the brain, which is often responsible for the fatal issue. When there is no external wound, the point at which the skull is to be opened is determined by the symptoms; for example, paralysis of the arm and face on one side indicates trephining over the centres governing these parts on the side opposite to the paralysis. If the bleeding cannot otherwise be arrested it may be necessary to ligate the external carotid artery. It has been suggested by J. B. Murphy that, when the patient is seen while the symptoms of compression are coming on, instead of trephining, the hæmorrhage from the meningeal vessels should be arrested by applying a ligature to the external carotid, under local anæsthesia. Injury to the #internal carotid# artery within the skull may result from penetrating wounds, or may be associated with a fracture of the base. It is almost invariably fatal. In some cases a communication is established between the artery and the cavernous sinus, and an arterio-venous aneurysm is thus produced. Ligation of the internal carotid in the neck or of the common carotid is the only feasible treatment.