exist apart from the bacterial chromosome, and that they carry specialized information for survival. Under selective pressure from antibiotics, one species of bacteria can pass its plasmids to another directly without mating, thereby preserving its own specialized survival genes. In 1966, he joined Georgetown University School of Medicine as a professor of microbiology. He later moved to Seattle to join the faculty of the Department of Microbiology and Immunology at the University of Washington School of Medicine. Here he described how meningitis and gonorrhea organisms acquire plasmids to become resistant to penicillin and other antibiotics. In the 1970s, Falkow shifted his focus to the infection process. During this period, he showed that a life-threatening diarrhea prevalent in many developing countries is caused by a sub-type of E. coli. He also co-authored (with Royston C. Clowes, Stanley N. Cohen, Roy Curtiss III, Naomi Datta and Richard Novick) a proposal for uniform nomenclature for bacterial plasmids. In 1981, he was named chairman of the Department of Medical Microbiology at Stanford University School of Medicine, a position he held until 1985. While at Stanford, Falkow encouraged Esther Lederberg to continue directing the Stanford Plasmid Reference Center, an internationally used registry for plasmids, transposons and insertion sequences.) Personal life and death Falkow was married to Rhoda Ostroff in January, 1958 with whom he had two daughters. They divorced in 1983. In December, 1983, he married Lucy S. Tompkins. Falkow and Tompkins met while he was a professor at Georgetown University, and she was a medical student who sought Falkow out to work in his lab. At first, Falkow denied the opportunity to Tompkins, claiming that he would not take female graduate students because he was not comfortable having a female student, which was common in the scientific field in the 1960s. Tompkins rebutted his misogyny firmly, and explicitly pointed out that he was discriminating against her based on her gender. Her argument forced Stan to reconsider his bias and he then allowed her to enter his laboratory as a trainee. For the remainder of his career Falkow continued to hire women trainees, and by the end of his career most of his trainees were female. Falkow later became an advocate and ally of gender equality in science and helped encourage many women to pursue scientific careers. Falkow had on-going severe anxiety throughout his career. Due to his anxiety early in his career he avoided