George Wald, a biologist who won the Nobel Prize for his work on how the eye processes images, has died at age 90.
Wald, who died Saturday at his home, had a later career as a human rights activist, traveling the country to speak out against Vietnam and nuclear arms and presiding over international tribunals investigating human rights abuses.
He shared the 1967 Nobel Prize in Medicine or Physiology with two other scientists for his work on how light causes the chemical reactions that send impulses along the optic nerve to the brain.
Upon accepting the award, Wald said: “A scientist is in a sense a learned child. There is something of the scientist in every child. Others must outgrow it. Scientists can stay that way all their lives.”
Wald also helped discover vitamin A in the retina as a National Research Council fellow in Germany in 1932. Hitler’s rise to power forced him to leave Germany for the University of Chicago.
Wald declared his opposition to the United States’ involvement in Vietnam in a March 4, 1969, speech at the Massachusetts Institute of Technology: “A Generation in Search of a Future,” which was widely reprinted and translated into several languages.