A compound or alloy of potassium and sodium - kalium-natrium, in the form of a soft, almost semi-fluid mass prepared by Dr. Emil Schreier, and employed for the treatment of putrescent pulp-canals. Dr. Schreier claims that when these two alkali metals are inserted into the pulp-canal they come in contact with a watery liquid, when immediately violent reaction takes place, the water is decomposed, with the development of considerable heat, by the production of potassium and sodium hydroxide and hydrogen. The sodium and potassium hydroxides unite with the fatty substances to form soap, which accounts for the characteristic odor. The compound, which is contained in a tube, is applied to the root-canal as follows: When the cork stopper is removed a paraffin layer covering the preparation is exposed. A barbed nerve-extractor is then pushed through this paraffin layer into the preparation, and upon gently withdrawing the instrument small particles of the potassium and sodium compound adhere to the barbs of the instrument, in which condition it is ready for introduction into the pulp-canal. Dr. Schreier advises care as to its use, especially avoiding an excess at any one application; otherwise the action would be too violent. The rubber-dam should be applied in all cases. Practical tests of this compound have given satisfactory results.