Chlorine should be used when the color is an oxidizable compound, or rich in hydrogen; while sulphurous acid should be used more particularly in substances highly oxidized and capable of being reduced. There are a great many different agents used for the bleaching of the teeth, but I will not consume any more of your valuable time, as I find that my paper is already quite lengthy. * * * * * DR. W. N. MORRISON is very proud of his son, who carried off the gold medal at the Missouri Dental College. INCIDENTS AND ACCIDENTS OF OFFICE PRACTICE.[1] BY H. H. KEITH, D.D.S., ST. LOUIS. There are no more useful lessons than those contained in the incidents and accidents of office practice. If we do not communicate the knowledge gained, the event is limited to the individual. Not alone should we record our successes and apparent achievements, that we may stimulate the energy of the younger members of our profession, but as faithfully read the story of our failures. In 1877, “S. A.,” a boy of ten years of age was presented with a mesial corner of the right superior central incisor broken in such a manner that the pulp, though not exposed, had died. The tooth was much discolored, abscessed, and very loose. A few days treatment sufficed to bring the tooth into a comfortable condition, when the boy's visits ceased. Some time elapsed: when he next came the tooth was elongated fully one-half the length of crown. The gums presented a most unfavorable appearance, and extraction was at once pronounced as the only proper treatment. At the earnest solicitation of the boy's mother this was deferred until the next day, and such treatment applied as the case seemed to indicate. Just here it may be well to say that exploration showed the root was not fully developed, the canal being quite large and funnel-shaped. So marked was the improvement the next day, that all idea of extraction was dismissed, and the root was finally filled with gutta-percha. A temporary filling of oxyphosphate was then introduced, and allowed to remain for two years. Then the contour was restored with gold. This filling was again replaced six years later with another of gold, which remained to within a short time ago, when a porcelain faced crown took its place. Deferring extraction to the next day has saved this tooth for thirteen years so far, with prospects of many years valuable service yet.