Sphygmograph.

Sphygmograph. an instrument for indicating changes of tension in the blood in an artery; practically a pulse-recorder. It was invented by Vierordt, and perfected in 1863 by M. E. J. Marey of Paris. When the instrument is applied to an artery a moving point traces a record on a band of paper moved by clockwork. A sphygmophone is a sphygmograph combined with a microphone. A sphygmoscope renders the pulsations visible. See works by J. B. Sanderson (1867), Dudgeon (1882), Bramwell (1883), and Keyt (1887).