Carl Bergmann

Carl Georg Lucas Christian Bergmann, also known as Karl Georg Lucas Christian Bergmann, was a German anatomist, physiologist, and biologist. He developed Bergmann's rule. He microscopically examined the cells of the retina to determine which of them convert light into neural signals that lead ultimately to visual perception: the cones and the rods. Bergmann also coined the terms fovea centralis, homoiothermic, and poikilothermic.