During the past decade injuries to the brain have been analyzed in greater detail than ever before. The recognition of localizing signs and symptoms consequent to these injuries, from the standpoint both of prognosis and of treatment, is of great importance. For example, in a group of cases of injury to the head the cranial nerves may be studied collectively, or one's attention may be profitably limited to the study of a single nerve and its intracranial ramifications. The following observations are confined to injuries of the optic nerves and their pathways, as revealed by alterations in the visual fields.
Loss of vision, a serious complication following head injuries, fortunately is not frequent. Phelps1 found injury to the optic nerves six times in two hundred and forty-five cases of fractures of the base of the skull (2.4 per cent). This relative infrequency is surprising when one considers the extensive