Dr. Anna Wessels Williams (1863–1954) was an American pathologist at the first municipal diagnostic laboratory in the United States. She used her medical training from the Women's Medical College of the New York Infirmary for research rather than medical practice, and over the course of her career worked on developing vaccines, treatments and diagnostic tests for many diseases, including diphtheria, rabies, scarlet fever, smallpox, influenza, and meningitis. Notably, a strain of diphtheria-causing bacteria that Williams isolated and cultivated was instrumental in producing an antitoxin to bring the disease under control. In 1932, she became the first woman to be elected chair of the laboratory section of the American Public Health Association. Early life Anna Wessels Williams was born in 1863 in Hackensack, New Jersey, to Jane Van Saun and William Williams. After graduating from a local high school in 1883, she became a schoolteacher. Life of Williams was to change course in 1887, when her sister Millie narrowly escaped death giving birth to a stillborn child. Anna believed that the poor training of the doctor in attendance was partly to blame for the tragedy, and so she resolved to resign from her teaching position and retrain as a physician. Later that year Williams enrolled in the Woman's Medical College of the New York Infirmary, where she was taught by Elizabeth Blackwell and Mary Putnam Jacobi. Williams later wrote: I was starting on a way that had been practically untrod before by any woman. My belief at the time in human individuality, regardless of sex, race, religion or any factor other than ability was at its strongest. I believed, therefore, that females should have equal opportunities with males to develop their powers to the utmost. After graduating in 1891, Williams taught pathology and hygiene at her alma mater, and underwent further medical training in Vienna, Heidelberg, Leipzig, and Dresden. Research career Work on Diphtheria In 1894, Williams volunteered at the New York City Department of Health's diagnostic laboratory, the first municipal laboratory in the United States, which had opened just a year earlier in response to a cholera outbreak. Williams worked closely with the director, William H. Park, on his projects to tackle diphtheria. In her first year of work she was able to isolate a strain of the diphtheria bacillus which could be used to produce the antitoxin for diphtheria, discovered in 1890, in large quantities. This crucial discovery massively