In 1694, Nicolaas Hartsoeker, in his Essai de Dioptrique concerning things large and small that could be seen with optical lenses, produced an image of a tiny human form curled up inside the sperm, which he referred to in the French as petit l'infant and le petit animal. This image, depicting what historians now refer to as the homunculus, has become iconic of the theory of preformationism, and appears in almost every textbook concerning the history of embryological science.[1]