HARTLINE, Haldan Keffer

(b. 22 December 1903 in Bloomsburg, Pennsylvania; d. 17 March 1983 in Fallston, Maryland), neurophysiologist who shared the 1967 Nobel Prize in physiology or medicine for "discoveries concerning the physiological and chemical visual processes," with Hartline's work being cited for its contribution to the understanding of the physiological mechanisms of vision.

The son of Daniel Schollenberger Hartline and Harriet Franklin (Keffer) Hartline, Hartline was known to family and colleagues as "Keffer." Hartline's father taught science and his mother taught English at the Bloomsburg State Normal School (later Bloomsburg State College). His parents shared their strong interest in the natural sciences with their only child.

Hartline attended Lafayette College in Easton, Pennsylvania, where he became interested in research on phototropism from reading about work done by the biophysiologist Jacques Loeb. His first scientific paper was on the visual responses of land isopods. During his college years, Hartline spent his summers at the Woods Hole Marine Biological Laboratory in Cape Cod, Massachusetts. There he met Loeb, who introduced him to Selig Hecht, a biophysicist recognized for vision research. He also met the American biologist George Wald, with whom he would share the Nobel Prize in physiology or medicine. Hartline's scientific future was enormously influenced by these early experiences.

After graduating from Lafayette with a B.Sc. in 1923, Hartline went to Johns Hopkins University in Baltimore, where he earned an M.D. in 1927. He was more interested in studying mathematics and physics than medicine, and often said facetiously that he was awarded the M.D. on the condition that he never practice medicine. At Johns Hopkins, Hartline used a sensitive galvanometer to conduct pioneering research on retinal action potential that contributed to the groundwork for electroretinography.

After receiving his medical degree, Hartline briefly studied mathematics and physics at Johns Hopkins and at the universities of Leipzig and Munich in Germany. In 1931, at the invitation of Detlev W. Bronk, the director of the Eldridge Reeves Johnson Foundation Laboratory at the University of Pennsylvania in Philadelphia, Hartline took a position in medical physics at the foundation. On 11 April 1936 Hartline married Elizabeth Kraus, the daughter of a well-respected chemist. They settled into a country home in Hydes, Maryland, and raised their three sons there.

Hartline met the Swedish neurophysiologist Ragnar Granit, his other Nobel cowinner, while at the Johnson Foundation. When Bronk became the president of Johns Hopkins in 1949, he appointed Hartline as the first professor of biophysics and chair of the new laboratory. Four years later Bronk became the president of the Rockefeller Institute of Medical Research (later Rockefeller University) in New York City and again appointed Hartline as the head of biophysics. When he took the position at Rockefeller, Hartline moved into a small apartment in the city that he dubbed a "winter camp"; his family stayed at the "summer camp" in Maryland, and he returned there for weekends and holidays.

During the 1960s Hartline continued conducting research at the Rockefeller Institute and frequently returned to Woods Hole. In 1967 he was awarded the Nobel Prize in physiology or medicine, along with Wald and Granit. Although he never collaborated with either of them, Hart-line was aware of, and admired, the research of both of his cowinners. Throughout his career, Hartline conducted all of his research in collaboration with colleagues and generously acknowledged all who influenced his work.

At the 1967 Nobel award ceremony, C. G. Bernhard noted that Hartline was given the prize for his elegant analysis of impulse generation in sensory cells and the code they transmit in response to illumination of different intensity and duration, research that provided the basic understanding of how sensory cells evaluate light stimuli. In his Nobel lecture, on 12 December 1967, Hartline described his work: "C. H. Graham and I sought to apply to an optic nerve the technique developed by Adrian and Bronk for isolating a single fiber; we made a fortunate choice of animal. The xiphosuran arachnid, Limulus polyphemus, commonly called 'horseshoe crab,' abounds on the eastern coast of North America. These 'living fossils' have lateral compound eyes that are coarsely faceted and connected to the brain by long optic nerves." The horseshoe crab is sometimes also described as a contemporary of the dinosaurs. Its eye has roughly 1,000 clusters of photoreceptors, where the human retina has more than 100 million photoreceptors.

Among the discoveries Hartline and his colleagues made from their work with the eyes of horseshoe crabs was lateral inhibition, which in the horseshoe crab's eye was shown to be mediated by simple neural connections. As Bernhard explained in his 1967 Nobel presentation speech, "After having shown the interconnections of adjacent visual cells, Hartline employed his discovery in a most imaginative way in order to obtain a quantitative description [of] how a nerve-net processes the data from sensory cells by means of inhibition. His discoveries have in a unique manner contributed to our understanding of the physiological mechanism whereby heightened contrast sharpens the visual impression of form and movement."

Commenting on Hartline's modus operandi, Bernhard said, "Your laboratory has been described as a slightly disorganized but extremely fertile chaos," adding that Hartline's work was best characterized for its elegance in design, expertise in manipulation, and clarity of exposition. Although the horseshoe crab has large photoreceptors and a long optic nerve compared to other species Hartline might have studied, the work still required demanding microdis-section skills.

Ironically, in 1967 when Hartline was awarded the Nobel Prize for his intricate research into the visual processes of the eye, his vision was slowly failing as a result of senile macular degeneration. Hartline commented to friends, "The loss of central vision is bad enough in itself, but to be prematurely labeled senile only adds insult to injury." In 1974 Hartline retired from Rockefeller University. He died from a heart attack at the age of seventy-nine.

Hartline's research in the 1960s culminated with the successful development of theoretical predictions of sensory cell responses to a wide variety of stimuli. This work provided the foundation for major advances in the neuro-physiology of vision.

A collection of Hartline's writings is Floyd Ratliff, ed., Studies on Excitation and Inhibition in the Retina: A Collection of Papers from the Laboratory of H. Keffer Hartline (1974). Biographies of Hartline include information in the Nobel archives, HaldanKeffer Hartline—Biography (1967); Harriet Zuckerman, Scientific Elites: Nobel Laureates in the United States (1977); and Floyd Ratliff, Haldan Keffer Hartline: December 22, 1903 to March 18, 1983 (1990). An obituary is in the New York Times (19 Mar. 1983).

M. C. Nagel