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

The silver plate is to be placed upon the lower denuded blister, while the zinc plate is planted also over the upper denuded blis- ter, when the connecting wires from each are brought together, and twisted into secure contact. But the joined conductor must be perfectly insulated from the skin and wet cloths. The blister, over which the zinc plate was bound, is found, in the course of a few hours, to be coated with a whitish-looking film, as if the chloride of zinc had been applied to it. In forty-eight hours an eschar is produced, which begins to separate some four or five days afterwards. The eschar is produced by the chemi- cal action of the continuous current in decomposing the effused fluids on the surface of the blister. The chloride of zinc thus gradually formed, and as gradually applied, by the electro-chem- ical action, produces the new sore that will now freely discharge pus when a common poultice is applied to it. While this pro- cess is going on the patient is usually quite free from pain, but the author has known some decided exceptions. Where it does prove painful it had better be at once removed, for after a little time it can often be reapplied without the suffering. Dr. Bird advises the blisters to be the size of a half dollar or dollar, and to always apply the zinc plate (which is of the same size of the blister) nearest to the head of the patient, while the silver, which is the same size, is farthest from the head, and nearest the ex- tent of the extremity, as, for instance, of the hand or foot. Over each plate, water or salt-and-water dressing is applied, and, above this, oiled silk or rubber cloth, merely for the purpose of retaining the moisture ; while flannel or warm clothing covers over the whole. Recainter's galvanic poultice has been found useful for rheu- matisms, lamenesses, weakness, amenorrhoea, &c.; but it appears to be much like the old voltaic pile, valuable for only a short time, and is soon corroded and exhausted beyond any efficiency. This consists of pieces of cotton wool, which contain ribbons or minute pieces of zinc and copper, each pair being separated by flannel. The cotton is placed in a bag, the one side of which is made air-tight, i. e., of oil cloth or rubber, and the other side or half of the bag is made of cotton cloth. The permeable or cot-