Study of the venous channels of the head had no great interest for most aural surgeons until a comparatively recent period; for, their important relations to septic processes in the ear and throughout the body were known and appreciated by few. Many knew that the sigmoid sinus lay uncomfortably near to their field of operation in opening the mastoid, and gave their attention largely to its avoidance. Latterly, among general surgeons especially, there has been rather a swing in the opposite direction in their readiness, on slight occasion, to expose and explore this sinus and take other liberties which better judgement and more diagnostic acumen would have showed them to be needless. Important as is this channel, it is far from being the only one demanding thoughtful consideration in a case of otitic pyemia.
The position and relation of the great sinuses of the brain need not detain us, for