Other marine organisms draw neuroscientists and neurobiologists to the MBL each summer, where a history of research into sensory physiology and behavior has been established. Haldan Keffer Hartline, an MBL summer investigator in the 1920s and early 1930s, uncovered several basic mechanisms of photoreceptor function through his studies on the horseshoe crab. Hartline shared the 1967 Nobel Prize with summer MBL colleague George Wald, who described the molecular basis of photoreception by showing that the light-sensitive visual pigment molecules consist of a slightly modified form of vitamin A coupled to a protein. Another long-term summer investigator, Stephen W. Kuffler, is credited with “founding” the science of neurobiology in the mid-1960s at Harvard Medical School and he also initiated instruction in neurobiology at the MBL (Barlow et al., 1993:175-234; 203-234). Albert Szent-Györgyi (Nobel Laureate in 1937) conducted research at the MBL from 1947 to 1986, most significantly on the biochemical nature of muscular contraction. In the 1950s and 1960s, Frederik Bang and Jack Levin at the MBL discovered that the blood of the horseshoe crab clotted when exposed to bacterial endotoxins even in vanishingly small amounts. From this basic research, a reagent, Limulus amoebocyte lysate (LAL), was developed that can detect minute amounts of bacterial toxins. The LAL test has resulted in dramatic improvement in the quality of drugs and biological products for intravenous injection.