Several months since, while conducting an experiment upon capping exposed dental pulps, I discovered what I consider a generous anodyne for sensitiveness and toothache incident to soft white decay. Believing that dentine was to some extent renascible, and knowing that the dental pulp possessed great recuperative powers, I was impressed with the idea that something might be found that, as a local application, would induce the growth of a bony covering over the point of exposure of the pulp, in a comparatively short time.