With respect to the details of the operation, two courses are available: (1) examination of the meninges and brain at the seat of injury, and (2) a ‘decompression’ operation. The former course should be adopted whenever the local conditions are favourable, that is to say, whenever depression or absence of bone, localized headache, &c., suggest a localized lesion. Under other circumstances Cushing’s intermusculo-temporal method of decompression should be carried out. This operation should be conducted first over the right temporal region, thus avoiding all possibility of inclusion of Broca’s area, a similar operation being done on the left side at a later date in the event of incomplete success. =Traumatic cephalalgia.= Of all the after-results of head-injuries, headache is the most constant symptom, either localized to the region primarily involved or diffuse. Even when diffuse, however, the aching is frequently referred to the frontal region. Localized headaches are the more acute. The patient can place his finger over the site of the trouble with accuracy and constancy. Examination on the part of the surgeon causes him to wince or cry out. Percussion with the tip of the finger not only leads to marked exacerbation but also induces a dull aching sensation, which lasts for some time afterwards. Whether acute or dull, exacerbations are of frequent occurrence, and during these attacks the patient is entirely incapacitated, desiring nothing more than to be left alone. In some cases the pain is referred along the course of one of the superficial nerves, in which case it is probable that the affected nerve is caught up in the scar. Headache, of whatever nature, is increased by exertion, indulgence in alcohol, exposure to the sun, &c. Crisp English considers that many cases of localized headache are dependent on a localized chronic osteitis, and recommends trephining and removal of the affected bone. There can be no doubt that the mere removal of a disk of bone will occasionally bring about a cure, but, from my own experience, I take a different view with respect to the pathological lesions present. I have operated on over a dozen cases of chronic cephalalgia, and I have found in nearly every case definite pathological lesions--depression of internal table, thickening of the meninges, subdural cysts and subdural hæmatomata. The mere removal of a disk of bone may relieve the symptoms by reducing the local pressure or by removing a source of meningeal irritation, but such treatment seldom brings about permanent relief. The dura mater should be opened in nearly every case, the frequent discovery of a subdural complication--cyst or hæmatoma--showing that such a course is necessary.