Haldan Keffer Hartline

Haldan Keffer Hartline was an American physiologist who shared the 1967 Nobel Prize in Physiology or Medicine with George Wald and Ragnar Granit for his analysis of the neurophysiological mechanisms of vision. He graduated from Lafayette College in 1923 and received his medical degree from the Johns Hopkins School of Medicine in 1927, then studied in Leipzig and Munich before building his career at the University of Pennsylvania, Cornell Medical College, Johns Hopkins University and, from 1953, Rockefeller University. Working mainly on the eye of the horseshoe crab, he obtained the first record of the electrical impulses of a single optic nerve fibre and showed that neighbouring photoreceptor cells depress one another, which sharpens contrast and the perception of shapes. He was elected to the United States National Academy of Sciences in 1948 and became a Foreign Member of the Royal Society in 1966.