_Perforation of the Cranium_ is not often resorted to since the treatment of injuries of the head has become better understood. In former times, the operation of trepan was performed frequently, and many seemed to rate the dexterity and science of a surgeon by the number of holes which he was able to bore in the skull of an unfortunate patient. It ought never to be performed, unless the necessity for, and the propriety of, the proceeding be clearly indicated. It used to be practised in a most unlimited manner for fissure: cracks were sought for with the greatest care, rules were propounded to enable the surgeon to distinguish fissures from the cranial sutures, and from furrow made in the bone by periosteal vessels; and the trepan was frequently applied over each part of the fissure, however extensive it might be, the only apparent end of the operation being to widen very materially the solution of continuity in the cranium. It was also resorted to in cases of compression without fracture, with the view of discovering the effused fluid, and removing it; but, as was already stated, it is unwarrantable in such cases; and much more so in concussion, for which latter accident, however, it has been occasionally performed. I met with a case some years since, in which the patient was certainly not much benefited by such active practice. The operation is of itself attended with danger, and likely, under many circumstances, to aggravate the patient’s symptoms, and diminish his chance of recovery.