Despite the fact that the subject of focal infection has been prominently before the medical profession during the past decade, a good deal of confusion and skepticism of its importance still exists. One ordinarily thinks of only the acute bacterial infections and especially of the specific infections and contagious diseases in relation to infection, but it has been estimated that from 80 to 90 per cent of all deaths are due to some type of infection, and the acute specific infections are in reality responsible for but a small part of these. To not a few physicians the subject of focal infection begins and ends with the possibility of a deforming arthritis being related to infected teeth or tonsils, the removal of which may or may not be followed by a magical disappearance of the joint involvements. But the possible importance of simple nonspecific infections of the apexes of the