Philippe Ricord was a nineteenth-century physician and surgeon in France who studied syphilis and demonstrated that it is different from gonorrhea. As of 2024, researchers recognize that syphilis and gonorrhea are both sexually transmitted infections, or STIs. However, the bacterium Treponema pallidum causes syphilis, leading to symptoms such as sores and fever, whereas the bacterium Neisseria gonorrhoeae causes gonorrhea and leads to different symptoms such as discharge from the urethra. Before Ricord, researchers thought syphilis and gonorrhea were the same disease. Ricord, through observation and experimentation, distinguished syphilis from gonorrhea and arranged the stages of syphilis into primary, secondary, and tertiary, each associated with different symptoms and levels of severity. By distinguishing syphilis from other STDs and accurately categorizing its stages, Ricord helped researchers better understand how to treat syphilis, a disease that can be transmitted from mother to child, causing life-threatening illness in infants.