Müller (1820 - 1864), German physiologist and anatomist. In 1851, Müller noticed the red color in rod cells, now known as rhodopsin or rhodopsin, a pigment present in retinal rod cells. He also described glial cell fibers that make up the retinal support frame, a structure known as "Müller fiber." In 1856, together with his colleague Albert von Korric (1817-1905), he stated that the frog's heart would produce electricity every time it contracted. Since 1858 he has been a full professor at the University of Würzburg. As a lecturer, he also teaches system anatomy, histology and microscopy. Müller's muscle: The round part of the ciliary muscle of the eye. After the French physiologist Charles Marie Benjamin Rukit (1824-1904), it was also known as "Rouget Muscle". Sometimes referred to as "Müller-Rouget Muscle" to commemorate these two people.