The middle meningeal artery acts as a guide to the foramen spinosum, a foramen that lies immediately posterior and external to the foramen ovale. In many cases the position of this artery so hampers the operator in his manipulation that ligature is demanded. For this purpose Cushing’s silver ‘clips’ will be found most serviceable. One clip is applied to the artery immediately after its entry into the skull, the other a short distance above, the vessel being divided between the two (see Fig. 6). The foramen ovale is then identified, the dura being stripped away from the nerve trunk by blunt dissection. The surgeon then works inwards and forwards to the second division of the nerve and its foramen, the foramen rotundum. Hæmorrhage, in this case derived from emissary veins, may again be troublesome. Considerable perseverance is required, and, although each attempt at further separation of the dura from the bone entails more oozing, the difficulties--except in the most exceptional cases--may be overcome. The _second and third divisions may now be resected_. For this purpose it is essential that the two nerves should be exposed from the point of their exit from the skull right up to the margin of the ganglion. Their dural coat seldom requires to be incised with the knife, the membrane being readily stripped away with the blunt dissector. When fully exposed, the nerve trunks are picked up with a blunt aneurysm needle and divided in two places, flush with the basal foramina and close up against the ganglion. The intermediate parts are removed. To prevent regeneration of nerve fibres--with consequent return of symptoms--the basal foramina are blocked up with small ivory pegs--well driven home--or with amalgam. All gauze plugs are removed, the field of operation well dried, and dura and brain allowed to fall back into position. The wound is closed, if possible without drainage. In the event of considerable oozing a cigarette drain should be inserted for twenty-four hours. The scalp-flap is sewn up, skin, muscle, and fascia being united separately.