Scrofula is an infection of the lymph nodes in the neck. Most cases are caused by a type of tuberculosis bacteria. Today, it is treated and cured with antibiotics. However, no one knew the cause of scrofula until 1882 when Robert Koch discovered the tuberculosis bacteria. The antibiotic cure for tuberculosis was not developed until the 1940s.
Image courtesy of the National Library of Medicine.
To learn more about the history of medicine and quack cures, see Discovering Quacks, Utopias, and Cemeteries