In undertaking a series of experimental electrocardiographic studies, we found a large number of animals that were not suitable for our work. But before the adaptability of an animal could be determined with the usual experimental electrocardiographic electrode, it was necessary to anesthetize it and make an incision in the skin in order properly to insert the electrodes. This procedure requires considerable time and sometimes results in an infected wound if the animal is not used at once.
To obviate this difficulty we have adopted a very convenient type of electrode, consisting of an adjustable copper plate with an attachment for the lead wires. The width of the cuff is 1¾ inches, and the minimum diameter, after it has been bent roughly to conform to the shape of the leg, is 1 inch. The copper is flexible, and is readily adjusted to a large or small animal by means of