Four years ago we published a brief note1 on a feeding experiment, carried out at the Mississippi State Penitentiary, in which we reported the successful production of pellagra in some white male convicts. Preparation of the detailed report of this experiment was unavoidably delayed by the pressure of continuing field investigations, but has now been completed and is in course of publication.2 Because of the importance of some new points relating to the etiology of the disease that certain observations in connection with the experiment suggest, it has seemed worth while to present on this occasion a somewhat condensed report of this experiment and of the indications that it affords. PURPOSE The purpose of the experiment was to test the possibility of producing pellagra in previously healthy men by feeding a one-sided, monotonous, principally cereal diet of the type observed by us in other previous studies to be associated with