EVB2936431: Cowpox pustule on the arm of milkmaid, Sarah Nelme, which Edward Jenner used as a source for his smallpox vaccine / Bridgeman Images

EVB2933381: Mao Zedong and Zhang Guotao, c.1930 (photo) / Bridgeman Images

EVB2936480: Physical therapy patient using finger walker to increase flexibility and range of motion in shoulder. c. 1950 / Bridgeman Images

EVB2933387: Rosalyn S. Yalow (b. 1919) shared the 1977 Noble Prize for Medicine with Andrew V. Schally and Roger Guillemin for the development of RIA, radioisotope tracing, to measure substances in the blood. They did not patent their discovery, foregoing a fortune for the benefit of others. 1961 / Bridgeman Images

EVB2936533: Pharmacy scene from the title page of a Latin version of Galen's RECETARIO DE GALIENO, published in Venice in 1518 / Bridgeman Images

EVB2933412: CORE members swing down Fort Hamilton Parkway, Brooklyn, to join the 1963 March on Washington for Jobs and Freedom, Washington / Bridgeman Images

EVB2936674: Paul Ehrlich (1854-1918), German medical scientist experimented with chemical treatments to destroy pathogens and their ill effects on humans. His greatest discovery was an arsenic based medicine that was the first effective treatment for syphilis in 1910 / Bridgeman Images

EVB2933479: Susan B. Anthony (1820-1906), in 1890s / Bridgeman Images

EVB2936682: Robert Koch (1843-1910), German physician, who with Louis Pasteur, founded the modern science of bacteriology. He received the Nobel Prize for Physiology or Medicine in 1905 for his work on tuberculosis. 1887 portrait / Bridgeman Images

EVB2938446: The Reagans greet the Gorbachevs at the White House State for a White House State Dinner. Earlier that day Reagan and Gorbachev signed the INF Treaty eliminating nuclear and conventional ground-launched ballistic and cruise missiles with intermediate ra / Bridgeman Images

EVB2938449: President and Nancy Reagan meeting with Pope John Paul II at The Vatican. June 7 1982 / Bridgeman Images

EVB2938455: President and Nancy Reagan having tea with Prince Charles and Princess Diana in the White House Residence. Nov. 9, 1985 (b/w photo) / Bridgeman Images

EVB2938464: President Reagan and Mrs. Reagan attending a memorial service for Lebanon and Grenada casualty victims Camp Lejeune North Carolina. 241 U.S. service members were killed and 80 seriously injured in the Beirut barracks bombing of Oct 23 1983. In Grenada / Bridgeman Images

EVB2938481: Predator Unmanned Aerial Vehicle flies above the aircraft carrier USS Carl Vinson on a Navy aerial reconnaissance test flight off the coast of California. Dec. 5 1995 / Bridgeman Images

EVB2938508: George and Barbara Bush in Houston Texas on the night which George Bush was elected to Congress in 1966 (b/w photo) / Bridgeman Images

EVB2938544: Crowds of Berliners around the Brandenburg Gate following the structure's official opening on Dec. 22 1989. In the foreground an East German guard walks on the Berlin Wall / Bridgeman Images

EVB2938580: THE CUSTOM HOUSE ORDEAL. Cartoon against protective tariffs which caused American travelers to undergo customs inspections searching for undeclared goods purchased abroad. A merchant the 'Dealer in Protected Goods ' snaps his whip to form the words 'Pro / Bridgeman Images

EVB2938636: John D. Rockefeller 1939-1937 with his bicycle after his retirement. 1913 photo / Bridgeman Images

EVB2938657: Alfred Berhard Nobel 1833-1896 Swedish chemist and engineer invented a detonator used with dynamite and nitroglycerin. From the fortune he made from his invention he established the fund for the Nobel Prizes. Portrait of 1885 / Bridgeman Images

EVB2938660: Alfred P. Sloan 1875-1966 chairman of General Motors covered his face with his hand during his testimony before the Congressional Monopoly Committee on May 18 1939 / Bridgeman Images

EVB2938677: Marie Dressler Anne Morgan and Jules Bache, c.1920 (photo) / Bridgeman Images

EVB2938693: Samuel Francis Du Pont 1803-1865 member of the Du Pont family of Delaware served in the Mexican-American War and the Civil War reaching the rank of Rear Admiral. 1850 ca / Bridgeman Images

EVB2938722: Hetty Howland Robinson Green 1835-1916 in the 1890s. Born into a Quaker family made wealthy by whaling she inherited 7.5 million in 1864 which she grew to over 100 million making her the world's richest woman / Bridgeman Images

EVB2938735: Amadeo Peter Giannini 1870-1949 with his family aboard S.S. Guilio Cesare on July 13 1923. Giannini was the Italian American founder of Bank of America which he first opened under as the Bank of Italy in 1904 to serve immigrant laborers discriminated / Bridgeman Images

EVB2938751: YOUNG AMERICA'S DILEMMMA. Cartoon comparing the million dollar salary of U.S. Steel manager Charles M. Schwab with the 10 500 salary of Supreme Court Chief Justice. Louis Dalrymple cartoon was published in PUCK on Sept. 12 1901 / Bridgeman Images

EVB2938767: District chief Abdul Qayum center speaks to Afghan elders during a shura in Zabul province Afghanistan. Qayum discussed security in the district and the upcoming parliamentary elections. Sept. 8 2010., Photo by:Everett Collection / Bridgeman Images

EVB2938790: U.S. Marines with conduct a census patrol in Sangin Afghanistan a Taliban stronghold to suppress enemy activity and gain the trust of the people., Photo by:Everett Collection / Bridgeman Images

EVB2938793: Southern Alliance fighters outside the Kandahar International Airport during the first months after the al Qaeda 9/11 terrorist attacks. Jan. 14 2002., Photo by:Everett Collection / Bridgeman Images

EVB2932430: Marion Morgan dancers on a Washington, D.C. Beach in 1923. They popular vaudeville troop performed ballets based on classical legends / Bridgeman Images

EVB2932434: Charles M. Schwab (1862-1939)in Washington in 1920. He made over 200 million dollars in the steel industry and was one of the business giants of the U.S. from 1900-1930. His fortune was wiped out during the Great Depression / Bridgeman Images

EVB2932437: William Cullen Bryant (1794-1878) was an influential editor of the New York Evening Post for 50 years, and promoted human social equality, including abolition. He was among the founders of the Republican Party / Bridgeman Images

EVB2932506: Percival Lowell (1855-1916) American Astronomer, founder of the Lowell Observatory at Flagstaff, Arizona. He planned the observations of Nepture that lead to the discovery of Pluto / Bridgeman Images

EVB2932565: Early calotype by photographic pioneer David Octavius Hill (1802-70) "Newhaven fisherboy. " of 1844 / Bridgeman Images

EVB2932628: Chester Himes (1909-1984) expatriate African American "noir" novelist, writer of detective novels and stories. 1946 / Bridgeman Images

EVB2932656: Joseph Addison (1672-1719), intertwined his political and literary careers, accepting commissions to create poetry celebrating royalty and British history, and holding a seat in the House of Commons / Bridgeman Images

EVB2932701: Walter V. Clark (1909-1971), novelist wrote about the American West, best known for the "The Ox-Bow Incident," (1940) / Bridgeman Images