Development of Dentin Sclerosis**Work supported in part by a grant from the Research Commission of the American Dental Association.From the Research Laboratory of the School of Dentistry, University of Louisville.Read before the Section on Histology, Physiology, Pathology, Bacteriology and Chemistry (Research) at the Seventy-Sixth Annual Session of the American Dental Association, St. Paul, Minn., Aug. 8, 1934.