the first examples of 'adaptive enzymes,' now understood as the rapid transcriptional activation of the gene encoding the formate hydrogenlyase when the activator, formate, is added to the culture. Later in the 1930s Stephenson worked with Ernest Gale on enzyme adaptation and amino acid metabolism, and with Arthur Trim on metabolic studies of nucleic acids. During her time at the laboratory, Stephenson produced, as author or co-author, more than twenty papers. She is most widely remembered for her seminal book, Bacterial Metabolism, which ran to three editions between 1930 and 1949. Last reprinted in 1966, it was the standard work on the subject for generations of microbiologists and biochemists. Royal Society In 1902 Hertha Ayrton was the first woman to be proposed as a Fellow of the Royal Society but was rejected because the society's lawyers successfully argued that it was impossible for a woman to be a Fellow. The Sex Disqualification (Removal) Act 1919 and a Privy Council ruling on the legal status of women in 1929 rendered these arguments obsolete. But, it was not until 1943 when, spurred to action by a critical article in the Daily Worker by Jack Haldane, the Royal Society considered accepting women as Fellows. Charles Harington nominated Stephenson and, after a ballot in which a large majority of Fellows voted to accept women, she was duly elected in 1945 together with Kathleen Lonsdale. During the World War II, Stephenson served on the Toxin Committee. One of the founders of the Society for General Microbiology, and Alexander Fleming tried to induce her to take the role of the Society's first President, but she declined; Stephenson was elected as its second president in 1947. After the war the Rockefeller Foundation and the Medical Research Council funded a new laboratory at Cambridge (known as the "Bug Hut"), to which she moved in 1947. Stephenson was also influential in improving teaching of microbial biochemistry; she helped set up a special Part II Biochemistry (Microbial) in Cambridge in the same year. Also in 1947 she was finally recognised by the university for her many years of service; they appointed her as the first Reader in Chemical Microbiology, a permanent position. She died of cancer on 12 December 1948, a year after the university appointment. Her biographer said of Stephenson: "She made her way in science by pioneering her own field, and her life was her work and her