George Wald

Origins and early life

George Wald was born in New York City on 18 November 1906 to Isaac Wald and Ernestine Rosenmann, Jewish immigrants. He was in the first graduating class of Brooklyn Technical High School in 1923, took his bachelor's degree at New York University in 1927 and a doctorate in zoology at Columbia in 1932.

Work and career

A travel grant sent him to Europe, and in Otto Warburg's laboratory in Berlin he identified vitamin A in the retina — the first chemical link between diet and sight. He went on to Paul Karrer in Zürich, who had discovered vitamin A, and briefly to Otto Meyerhof in Heidelberg, but left Europe for the University of Chicago in 1933, when Hitler came to power and life there grew dangerous for Jews. In 1934 he joined Harvard, where he remained.

Wald worked out the chemistry of seeing. The pigment rhodopsin in the rods of the retina, he showed, splits when light strikes it into the protein opsin and a compound derived from vitamin A, and it is that splitting that starts the nerve signal — which is why a shortage of vitamin A brings night blindness. In the 1950s he and his colleagues measured how strongly retinal pigments absorb each wavelength, mapping the light the eye detects best; later, reading cell by cell with microspectrophotometry, he reached the cone pigments that give colour vision.

He shared the 1967 Nobel Prize in Physiology or Medicine with Haldan Keffer Hartline and Ragnar Granit. He died in Cambridge, Massachusetts, on 12 April 1997.