Because of its simplicity and ease of operation, and because it has certain technical advantages, I wish to describe an electrode for use when taking electrocardiograms of ambulatory patients. Electrodes consisting of a metal plate bound to the extremity by bandages wet with hot salt solution are commonly used for bed patients,1 but for ambulatory patients the zinc—zinc sulphate—salt solution type of nonpolarizable electrodes are recommended.2 These latter are a quite unnecessary complication of the technic. The simple electrode to be described will take technically perfect records.
It consists of a glass tank for each extremity, that for the arms being a cylinder about 7 × 10 inches and that for the leg being rectangular, about 7 ×7 × 12 inches (a fish aquarium). In these are stood metal plates 4 inches wide and extending up above the top of the tank, to which plates the wires from the galvanometer