show the presence of Negri bodies, which gave results in minutes rather than days. Her method surpassed the original test and became the standard technique for diagnosing rabies for the next thirty years. In 1907, when the American Public Health Association established a committee on the standard methods for the diagnosis of rabies, they named Williams chair of the committee in recognition of her expertise. Later Work In 1905, Williams was promoted to the position of assistant director of the Department of Health laboratory where she had worked since 1894. In this role, she worked toward the better diagnosis and treatment of venereal disease with Emily Barringer, M.D. and, in collaboration with Josephine Baker's Division of Child Hygiene, developed a better diagnostic test for trachoma, a disease that was claiming the eyesight of many of the urban poor, particularly children. During World War I, Williams directed a training program at New York University for the War Department, to train war workers for medical laboratories at home and overseas. She also researched methods for diagnosing meningitis carriers in the military. After the war ended, Williams was one of the scientists of the front lines of research trying to combat the deadly 1918 pandemic of Spanish flu. In addition to her laboratory research, Williams coauthored two influential books with William Park, with whom she continued to work closely after their collaboration on the diphtheria antitoxin. In 1905, the pair published their classic text Pathogenic Micro-organisms Including Bacteria and Protozoa: A Practical Manual for Students, Physicians and Health Officers which quickly became known simply as 'Park and Williams' by readers. By 1939 the publication had been reprinted in eleven editions. In 1929, Williams and Park published Who's Who Among the Microbes, thought to be one of the earliest biomedical reference books written for the public. Over the course of her career, Williams received many honours and awards. In 1915 she was elected president of the Woman's Medical Society of New York. In the 1920s, Williams had done extensive studies on scarlet fever. The Dick test, which was developed by George and Gladys Dick, was to detect the disease on thousands of children. William had surveyed hundreds of cases that were positively diagnosed with the disease for the antitoxin that had been used. In 1931 she was elected to an office in the laboratory section of the American Public Health Association and the following