The subsequent procedures vary according to the condition of the bone:-- _If there be no fracture of the bone_, the pin of the trephine is applied to the indented spot and the disk of bone removed. After the removal of the disk the clot will be exposed; but, in order to obtain full exposure, the gap must be enlarged with the craniectomy forceps, mainly in the upward and downward directions. _If a fissured fracture be found_, the trephine is applied in close relation to the intersection of the line of the artery and the line of the fracture, the gap being enlarged in the required direction. _When the fracture is comminuted_, the fragments of bone are either elevated or removed until sufficient room has been obtained. The greater part of the clot can be removed with a Volkmann spoon, or with an ordinary teaspoon, and the region flushed out with hot saline solution. _To secure the bleeding-points._ When the artery is injured beyond the limits of the gap, the bone must be nibbled away till the bleeding-point is exposed. In some cases it may be necessary to remove a considerable portion of the bone entering into the formation of the temporal fossa. In the meantime, hæmorrhage may be controlled by plugging towards the base of the skull with strips of gauze. Sufficient room having been obtained, the gauze is withdrawn, when smart sponging should enable the operator to determine the source of the hæmorrhage. At this stage of the operation, a head-lamp is useful. After the exposure of the bleeding-points, the following measures can be adopted whereby to arrest the bleeding:-- (_a_) The application of a ligature or of silver ‘clips’ (see Fig. 6) on either side of the bleeding-point. (_b_) The vessel may be underrun on either side of the bleeding-point. (_c_) The vessel may be seized with artery forceps and twisted. (_d_) The hæmorrhage may be arrested by means of gauze plugs. (_e_) The foramen spinosum may be occluded with bone or wooden pegs. (_f_) The common or external carotid arteries may be ligatured. Every effort should be made to control the hæmorrhage by means of ligature, silver clip, underrunning, or torsion. Gauze plugs may usually be relied on to stop the bleeding, but they possess the great disadvantage of exercising pressure on the cortex and preventing expansion of the brain. Occlusion of the foramen spinosum and ligature of the carotid arteries complicate and prolong the operation. The foramen spinosum is occluded in the following manner: the dura mater is quickly stripped up with the fingers away from the base of the skull, the soft parts gently but firmly retracted and the foramen identified. Its occlusion may be effected by means of a sterilized wooden match or bone peg, by a small piece of bone derived from those osseous fragments which have been removed during the operation, or with the aid of a piece of catgut; in each case the occluding medium should be well driven into the foramen.