After some discussion by Drs. Taft and Callahan, it was decided to appoint special committees in conjunction with the executive committee to adopt new methods. Paper by Dr. Otto Arnold, Columbus. Ohio: NON-METALLIC PLASTIC MATERIALS FOR FILLING TEETH. * * * “The employment of the earlier dentists of gums, mastic and sandarac, in etherial and alcoholic solutions for the stopping of cavities of decay, is the first approach history records of plastic fillings. About the year 1848, however, the first substantial progress was made in this direction by the use of gutta-percha as a temporary filling material. A little later, the well-known compound, Hill's stopping, was introduced, which is a modification of gutta-percha by the addition of certain mineral elements to make it harder, therefore more available for permanent fillings. * * * About thirty years ago, oxychloride of zinc was introduced, the first of a now well-known class of filling materials, viz.: the zinc plastics. Next in order came oxyphosphate of zinc, followed by enumerable modifications and combinations. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * “It cannot be denied that the introduction of gutta-percha and the zinc plastics was the beginning of an era in operative dentistry that made it possible to attain results never before brought about. Prior to that time little, if anything, had been accomplished in the direction of protecting pulps from the effect of thermal irritation. The solution of this problem alone is of such intrinsic worth as to make any material, capable of contributing to that end, of inestimable value. All preparations of the zinc plastics, likewise gutta-percha, at least so far as the writer has knowledge, are more or less non-conductors of caloric, therefore valuable for this purpose, and it is almost an unpardonable offense to ignore their use in all large cavities as a protection to pulps. * * * Gutta-percha, however, unless in solution of chloroform or other volatile solvent, is not wholly safe, unless the greatest care is exercised to prevent its introduction into the cavity in too heated a condition. This is a serious obstacle, as the minimum degree of heat necessary to plasticity may, especially if the pulp is near the surface, be sufficient to permanently injure this organ. The pressure generally necessary to adapt this substance to place, is another objection. So, nothing short of the greatest caution in its use will give certain results. Gutta-percha as a filling material, compared with the zinc plastics for inside use, and amalgam for outer surfaces, has a limited sphere of usefulness. * * * The oxychloride cement has an escharotic action on organized tissue, which makes it unsafe as a nerve capping; but when used in connection with an intervening layer of a non-irritant, it becomes useful for this purpose. It is decidedly antiseptic, but readily soluble in oral fluids, and is distinguished