Dr. Joseph-Ignace Guillotin was a French physician who proposed on 10 October 1789 the use of a device to carry out death penalties in France. While he did not invent the guillotine, and in fact opposed the death penalty, his name became an eponym for it. The actual inventor of the prototype was Antoine Louis.
Guillotin became one of the first French doctors to support Edward Jenner's discovery of vaccination and in 1805 was the President of the Committee for Vaccination in Paris. He also founded one of the precursors of the National Academy of Medicine.
The association with the guillotine so embarrassed Dr. Guillotin's family that they petitioned the French government to rename it; when the government refused, they instead changed their own family name.