|Louis Pasteur, portrait, Musée d'Orsay|
The story is told in the University of Paris that the philosophers there once disputed among themselves as to the number of teeth in a horse's mouth. It was argued that the number could not be a multiple of three, because that would imply disrespect to the Trinity; nor could it be a multiple of seven, for God created the World in six days and rested upon the seventh. Neither the authority or Aristotle nor the ingenuity of the schoolmen could resolve the problem, but it was finally settled by a young man, who opened the mouth of a horse, and counted the teeth. The doctors of the University were not convinced by this novel and unintellectual procedure; but the opening of the horse's mouth marks the birth of the scientific method.