Bretonneau was the first person to study and describe fully the symptoms of diphtheria, and gave the disease its name. He also believed there was a difference between typhoid fever and typhus, which were often mistaken as the same disease. In a time before anyone understood that pathogens (germs) cause disease and infection, Bretonneau suspected that these diseases were contagious, believing that diphtheria was transmitted between individuals from drinking glasses. His suspicion was an entire generation earlier than Louis Pasteur's germ theory.

Bretonneau was born in Saint-Georges-sur-Cher in France. His father, Pierre, was a master surgeon and his mother, Elisabeth Lecomte, was from a wealthy, upper-class family. Oddly enough, Bretonneau received virtually no education as a young child and was still unable to read at the age of nine. He was sent to the École de Santé in Paris in 1795 where he attended medical lectures, but...