Noguchi, Hideyo (hēdāˈyō nōgōˈchē) [key], 1876–1928, Japanese bacteriologist, grad. Tokyo Medical College, 1897. He came to the United States c.1900 to work with Simon Flexner at the Univ. of Pennsylvania and in 1904 joined the Rockefeller Institute (now Rockefeller Univ.) staff. He made important studies of snake venoms, of smallpox and yellow-fever vaccines, and of the laboratory diagnosis of trachoma. He isolated (1913) the Treponema pallidum from a syphilis patient, proving that this spirochete was the cause of syphilis; he also developed a skin test for syphilis. He died of yellow fever in Accra, Ghana, where he had been studying that disease. His writings include Action of Snake Venom upon Cold-Blooded Animals (1904) and Laboratory Diagnosis of Syphilis (rev. ed. 1923).