Ludwig, Carl Friedrich Wilhelm (1816-1895)

German physiologist who invented graphic methods of recording events within the body. He demonstrated that the circulation of the blood is purely mechanical in nature and involves no occult vital forces.

In 1847 Ludwig invented the kymograph, a rotating drum on which a stylus charts a continuous record of blood pressure and temperature. This was a forerunner of today's monitoring systems.

Ludwig was born in Witzenhausen, Hesse, and studied at Marburg (though temporarily compelled to leave the university as a result of his political activities), Erlangen, and the surgical school in Bamberg. He was professor at Marburg 1841-49, and then held posts at Zürich, Switzerland, and in Vienna at the Austrian military medical academy. From 1865 he was professor at Leipzig.

Ludwig devised a system of measuring the level of nitrogen in urine to quantify the rate of protein metabolism in the human body. In 1859 he described his mercurial blood-gas pump, which enabled him to separate gases from a given quantity of blood. He also invented the Stromuhr, a flowmeter which measures the rate of the flow of blood in the veins.

Ludwig published Das Lehrbuch der Physiologie/A Physiology Textbook 1852-56, the first modern text on physiology.