In exploratory operations conducted in cases of this nature, I have been particularly struck by the fact that in a large proportion of cases one finds what appears to be a condition of local œdema--some fluid beneath the dura mater, and a greater excess of the same in the pia-arachnoid meshwork. This œdema is a manifest condition readily demonstrated to onlookers. I am not an advocate of ventricular puncture in these cases, mainly on the ground that it complicates the operation and brings no added benefit in its train, but in such cases as it has been carried out the jet of cerebro-spinal fluid proves the added existence of an increased intraventricular pressure. From Leonard Hill’s experiments it would appear that this œdema is dependent on chronic vascular changes--arterial anæmia, venous congestion, and cerebro-spinal and serous accumulation. At a later date the meninges may become thickened and adherent to one another and to the surface of the brain, whilst false membranes and arachnoid cysts may develop. =Treatment.= For these more general and indefinite remote results of head-injury the treatment comprises REST, bodily and mental, light diet, fresh air, cheerful but quiet surroundings, and encouragement. Potassium iodide and mercury (preferably by inunction) often do good, whilst phenacetin and antipyrin are perhaps the best drugs for relief of headache. For sleeplessness potassium bromide is perhaps the best remedy. I have found in some cases that Turkish baths and massage have brought about considerable improvement. In advising such energetic treatment the surgeon must be guided by the case before him, these measures being more or less restricted to the less serious and more chronic cases. In the more serious cases, especially when slowing of the pulse during the height of the attacks and some blurring of the disks point to a probable increase of intracranial pressure, operative measures must be considered. The greatest circumspection is required in determining the class of cases in which operation may be proposed, and the surgeon must be most guarded in his prognosis. So far as my personal experience goes, the operation has invariably brought about some amelioration in the condition of the patient, whilst now and again a complete cure may be anticipated. Those cases which on exploration evidence an œdema of the brain are the least favourable; those in which the surgeon finds a subdural cyst or hæmatoma offer the best prognosis.