Samuel Hahnemann (1755-1843), German physician. Hahnemann founded homeopathy, the theory that an illness may be cured by administering minute doses of a drug which causes the same symptoms, thought to be an effect of the body's fight against disease. The smaller the administered dose, the greater its effectiveness. He published his results in 'Homeopathic Materia Medica' (1811). He used his methods with some success during a typhus epidemic in France in 1812. Although his results were criticised, homeopathy spread rapidly in the ensuing decades. Engraved by R. Woodman after an 1844 portrait by British artist George Edwards Hering (1805-1879).