Various methods han been resorted to for the purpose of alleviating the excruciating agony consequent upon the extraction of teeth ; but as the general anaesthetics are in all cases tedious and troublesome in their application, and often attended with fatal and dangerous results, sufferers, rather than experience the momentary pain of extraction, or run the risks of general or local anesthesia from the means heretofore employed, impair their health by retaining in their mouths diseased teeth and roots. To avoid the dangerous results of chloroform, and to do away with the employment of the not either harmless or efficient process of freezing mixtures to the jaw, Mr. Jerome B. Francis, of Philadelphia, has invented a method at producing local an?thesia by the application of an electric current, and through this means to effect the painless extraction of teeth. The application is simple, and consists in attaching to the forceps the negative pole or flexible wire of the ordinary electro-magnetic machine, or graduated battery, and placing the metallic handle of the otker or positive pole in the hand of the patient, and by this means to cause an interrupted current to traverse the body of the patient and the extracting instrument. The intensity of the current is previously graduated while the patient grasps the forceps and handle, until it is just distinctly perceptible, and the circuit through the tooth is not completed until the moment at which extraction is to begin. This interruption is said to be desirable until the forceps are placed upon the tooth, when the circuit is formed, and the extraction made at once. How this annuls pain we cannot determine, but that it has, in a large number of cases, we are satisfied from the representations of able dentists in this and other cities. This novel process of extracting teeth was patented the 25th of May, 1858, and the claim is to the combination of the electro-magnetic machine, with the dental forceps.