Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

introduced another tiny electrode, made for the purpose, of ivory, silver wire, and sponge, so as to insulate the wire except- ing its ends. This ivory ear electrode is two inches in length, one quarter of an inch in diameter at the outer end, and then tapered down to one twelfth of an inch at the smaller end. This is perforated lengthwise, so as to take a double loop of fine silver wire, that seizes a bit of the finest sponge, which is drawn firmly into the little cupped end of the ivory tube, and then clipped into a ball-shaped tip, while the wires pass through the instru- ment and appear at its outer end, whore they are secured and exposed convenient for contact. When this delicate instrument is carefully introduced into the ear, so that the moist sponge rests gently, and not painfully, against the moist membrane of the tympanum, and the patient is sitting in a reclining and easy posture, while the operator is seated behind him, then, whether employing primary or secondary, i. e.,Faradaic, or Galvanic cur- rents, the making and breaking of the circuit is done simply by applying the wire tip of the battery conductor to the silver pro- jection of the car electrode; and this will be found both prac- tical for the physician and agreeable to the patient, and attended not unfrequently with success, even in the very same cases where the old method had been attempted in vain. In this manner, the patient can bear more current, while this is all the better concentrated upon the enfeebled or paralyzed auditory nerve and the minute muscles of the internal ear, so that the operation is left more to the judgment of the physician than to the sen- sations and requests of the patient. For these reasons, we are to proceed with the utmost caution. It should be borne in mind that the zinc or negative -pole produces the greatest effects in the ear, while it is the silver or copper positive pole of the battery that exercises the greatest effects in the eye, nose, and mouth. The galvanic current makes a sound in the ear when the circuit is closed and while it remains closed, growing more and more intense until the circuit is opened. The induction currents cause the sound of a scratch ; or, if prolonged, the sound is like the buzzing of a fly, or the distant steam-whistle. Dr. Ritter says the pitch of these sounds is that of G. Dr. Althaus says it