Doctors Augustus Waller and Symes, St Mary's Hospital, London, 1884-1903.

Photograph taken in the old physiology lecture room at St Mary's Hospital Medical School. Between 1884 and 1903, physiologist Augustus Waller (1856-1922) carried out research into cardiology at St Mary's Hospital, publishing the first human electrocardiogram in 1887. It was recorded from Thomas Goswell, a technician at the laboratory. The Dutch physiologist Willem Einthoven (1860-1927) built on Waller's work and developed the electrocardiograph during the 1900s. An electrocardiograph detects and records the tiny electrical signals that coordinate the heart's beats, and which can indicate heart disorders. The signals ripple outwards and are picked up by metal sensors stuck to the skin.