Karl von Vierordt

Karl von Vierordt was a German physiologist, born in Lahr in Baden in 1818. He studied at Berlin, Göttingen, Vienna and Heidelberg, began medical practice in Karlsruhe in 1842, and became professor of theoretical medicine at the University of Tübingen in 1849 and professor of physiology there in 1853. He developed instruments for measuring the circulation of the blood, including an early hemotachometer for the speed of blood flow, and in 1854 built a sphygmograph, a lever and weight device for recording the arterial pulse that is seen as a forerunner of the sphygmomanometer. His treatise on the arterial pulse in health and disease was among his best known books. His 1868 book on the sense of time reported a large body of experiments on the perception of duration and gave rise to what is called Vierordt's law, that short durations tend to be overestimated and long ones underestimated. He died in Tübingen in 1884 at the age of sixty-six.