PREFATORY NOTE
Since the foundation of the Society of Clinical Surgery some twenty years ago, there has been a tendency for other limited groups of clinicians who have common problems, sympathies and interests to band themselves into migratory organizations which meet in rotation at one another's place of work. One of the youngest of these is the Society of Neurological Surgeons.Certain members of this society in their desire to advance information concerning a poorly understood and supposedly rare intracranial lesion have generously pooled their experiences in regard to it, so that a single individual might have at command sufficient material for a comprehensive study. Whether such a novel and unselfish program will lead to anything beyond the present report cannot be foreseen, but it at least sets a good precedent. Certainly such a composite of experiences is of greater value and will arouse wider interest than the mere presentation