This work was inspired by the splendid research on the regeneration of the mucous membrane of the maxillary sinus by Knowlton of Boston and McGregor of Toronto, and our first thought was to duplicate and confirm their observations. Since, however, this work had been so thoroughly done and was so convincing, we decided to transfer this investigation to the frontal sinus, as, in the first place, it was conceivable that the process of regeneration might vary in this cavity and, secondly, we could find no published reference to such an investigation.
The question, largely settled by Knowlton and McGregor, as to the type of membrane lining the accessory sinuses of the nose after surgical removal of the original mucous membrane, as practiced in most types of radical operation for the cure of infections of these cavities, has been present in the mind of every surgeon undertaking such radical operations,