Thinkers Timeline

Percy Lavon Julian (1899-1975) was an African American chemist whose pioneering synthesis of plant-derived steroids made cortisone and other hormone-based medicines widely available for the first time. He was born in Montgomery, Alabama, the grandson of former slaves. Alabama's public schools did not offer education beyond the eighth grade to Black children at the time, but his parents — a railway mail clerk and a teacher — insisted on his further education. He entered DePauw University in Indiana as what the institution called a sub-freshman, taking high school classes alongside his college studies, and graduated as valedictorian in 1920. American graduate programmes in chemistry were largely closed to Black students; he was refused admission at several top universities and taught for several years at historically Black colleges before winning a fellowship for graduate work at Harvard. Harvard gave him a master's degree but denied him the chance to teach or to complete a doctorate because of his race. He eventually earned his doctorate in Vienna in 1931, one of the few options then available. In 1935 he completed the total synthesis of the alkaloid physostigmine, used to treat glaucoma, beating a competing English group. Unable to get university chemistry positions because of his race, he joined the Glidden Company, a paint manufacturer, where he led research that developed industrial methods for producing steroids from soybean oil — processes that made cortisone affordable to patients with rheumatoid arthritis and opened the way to a generation of hormone-based medicines. He later founded his own company. He and his family faced racist violence in the Chicago suburb where they bought a house in 1950, including attempts to burn and bomb their home. He died in 1975. He was elected to the National Academy of Sciences in 1973, the second African American so honoured.

Dorothy Crowfoot Hodgkin was an English chemist. She remains the only British woman ever to win a Nobel Prize in any of the sciences. She was born on 12 May 1910 in Cairo, Egypt, where her father worked for the British colonial education service. The family later moved to Sudan. As a young child, Dorothy and her sisters were sent to live with relatives in England while her parents stayed in North Africa. She loved crystals from age ten, when she made her first crystals from chemistry kits. She was one of only two girls allowed to study chemistry at her school in Suffolk, where the subject was thought to be for boys. She studied chemistry at Somerville College, Oxford, from 1928 to 1932. She then went to Cambridge for her PhD with the crystallographer J. D. Bernal. In her mid-twenties she developed serious rheumatoid arthritis, which would deform her hands and feet for the rest of her life. She kept working anyway. She returned to Oxford in 1934 and worked there for the rest of her career. In 1937 she married Thomas Hodgkin, a historian who became an authority on African history. They had three children. She spent decades working out the three-dimensional structures of complicated biological molecules using X-ray crystallography. She solved the structure of penicillin in 1945, vitamin B12 in 1955, and finally insulin in 1969, after working on it for thirty-four years. She won the Nobel Prize in Chemistry in 1964. She died on 29 July 1994, aged 84.

Rosalind Franklin (1920-1958) was a British chemist and X-ray crystallographer. She was born in London into a prominent Jewish family and showed exceptional scientific ability from childhood. She studied chemistry at Cambridge University and then worked in Paris, where she became expert in X-ray crystallography: a technique that uses X-rays to determine the three-dimensional structure of molecules. She returned to England in 1951 to work at King's College London, where she was assigned to study the structure of DNA. Working with extraordinary precision, she produced some of the clearest X-ray photographs of DNA ever taken, including the famous Photo 51, which showed clear evidence of the double-helix structure. This photograph was shown to James Watson without her knowledge or permission by her colleague Maurice Wilkins. Watson and Francis Crick, who also had access to Franklin's unpublished data through other channels, used this information to build their model of DNA. Their paper announcing the double-helix structure was published in Nature in April 1953. Franklin was not credited as a contributor. She went on to do brilliant work on the structure of viruses at Birkbeck College before dying of ovarian cancer in 1958 at the age of thirty-seven. Watson, Crick, and Wilkins received the Nobel Prize for the discovery of DNA's structure in 1962.