Elizabeth M. Ramsey

Elizabeth Mapelsden Ramsey, M.D. (17 February 1906 – 2 July 1993) was an American physician, placentologist, and embryologist known for pioneering the study of early human embryos and the structure and circulatory system of the placenta. She was a researcher at the Carnegie Institution of Washington for nearly forty years. While performing an autopsy in 1934, she discovered a 14-day-old human embryo, the earliest yet studied at the time. Later in her career, Dr. Ramsey worked on a team that used cineradiology to reveal the workings of the placental circulatory system in primates.

Ramsey published over 125 articles and three books. Provided by Wikipedia