In 1950, one of Canada’s greatest medical innovations was developed at the University of Toronto’s Banting Institute. Cardiac surgeon, Dr. Wilfred Bigelow and research fellow, Dr. John Carter Callaghan were trying to understand how hypothermia (see Cold-Weather Injuries) could slow the beating of an animal’s heart before surgery. They were also looking for a way to stimulate the heart when it faltered as it cooled. This largely unknown area of research could have tremendous applications for humans. The doctors partnered with Dr. John A. Hopps from the National Research Council of Canada, who created a portable artificial external pacemaker. It was designed to send electric pulses to the heart, which caused the heart to contract and pump blood to the body. The device was successfully tested on a dog in 1950. This landmark discovery paved the way for the use of implantable pacemakers in humans.