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

When a patient is insulated and gradually charged from the prime conductor positively to a high degree of tension, and thus continued for a little while, during this if any pointed director is placed near him, the plus electricity is by it drawn off at that vicinity very quietly, and almost insensibly, only giving rise to the phenomenon called aura. This acts as a mild, hut most ex- cellent local alterative stimulus; as, for instance, about the eyes and breast. But if we remove the pointed director, and in its place use a ball, then the electricity is drawn off from the patient in sparks, which produce a pricking sensation, much as if the skin were touched with a pin or needle ; and the physio- logical result is also quite different. This succession of sparks produces much the same effect locally as the passage of a gentle voltaic current. The effect of these sparks (which can be made more seldom, long, and powerful, or rapid, short, and gentle, according as the brass ball is made to approximate, more or less, to the part) acts as a stimulus of a very peculiar kind; be- cause, as Dr. Golding Bird says, besides the simple discharge, there probably is accumulated and localized in the flesh positive electricity, at and near the spot where the sparks leave the body, which is thus maintained in wavering density. The skin soon becomes red, which shows its effects on the capillary vessels and at the roots of the hairs. Drawing sparks from the back of a cat is easily done in dry, frosty weather, particularly if pussy is near the fire, simply by first smoothing her fur with a very warm and dry silk, then lightly stroking the fur in the wrong direction, when she will soon give you to understand that she does not like it. These sparks have an in-working at the moist roots of the hairs, and are of the very minutest quantity, but of the highest possible intensity. It is well to know that in a room where the friction machine is being worked, every single object in that room is negatively electrified, if the rubber end of the machine is put in connec- tion with the room by means of a trailing chain over the table and floor, instead of being in connection with the earth ; and so can they become positively charged by reversing the order. High-pressure steam can be so directed through crooked tubes