Caduceus is a continuation of the older Indo-European dragon-slayer motif. Wilhelm Heinrich Roscher (1913) pointed out that the serpent as an attribute of both Hermes and Asclepius is a variant of the "pre-historic semi-chthonic serpent hero known at Delphi as Python", who in classical mythology is slain by Apollo. One Greek myth of origin of the caduceus is part of the story of Tiresias, who found two snakes copulating and killed the female with his staff. Tiresias was immediately turned into a woman, and so remained until he was able to repeat the act with the male snake seven years later.
The Crow and the Snake Croxall the story served as a warning against covetousness and for Thomas Bewick it illustrated the danger of being ruled by brute appetite. The latter interpretation had earlier been preferred by Guillaume La Perrière in his emblem book "Le theatre des bons engins" (1544). There the greedy crow is poisoned internally after swallowing the snake, “thinking it tasted good as sugar or venison”. The Crow and the Snake The Crow or Raven and the Snake or Serpent is one of Aesop's Fables and numbered 128 in the Perry Index. Alternative Greek versions exist and two of these were adopted during