Medieval doctors use to dress as huge birds with long beak's and feathered cloaks believing that the soul was delivered and despatched by the avian transmigration i.e stalk''s, babies , raven's omens cookoo's madness . To find an egg shaped lump of cancer that then hatches from its embryo into a fresh eating vulturous thing leaving behind an almost a dead skeleton could be perceived by the ancient superstitious to be the work of an avian devil .