Fick, Adolf Eugen (1829–1901),
German physiologist. A professor of physiology, Fick was an advocate of the school of physiology that sought to determine quantitatively the fundamental capabilities of the organism's components and then explain these on the basis of general physicochemical laws of nature. Fick did research in fields of notable diversity: molecular physics, including the diffusion of water and gases, porous diffusion, endosmosis, and filtration; hydrodynamics as applied to the motion of fluids in rigid and/or elastic vessels; the origin and measurement of bioelectric phenomena; optics; the theory of heat in physics and physiology; and sound. In 1856 he published a work that is often considered to be the first textbook of biophysics. In it he stated the fundamental laws governing diffusion, one of which is now known as Fick's law. Fick made outstanding contributions in hemodynamics, and in 1870 he stated the Fick principle for the measurement of cardiac output.