The healing serpent--the snake in medical iconography.

When Shelley invoked the snake symbolically in this fashion he was hardly doing anything new. The snake's association with death, rebirth and the cycle of nature is practically universal. For the ancient Egyptians the snake was the life of the earth, and there are texts from as early as 2300 B.C. referring to the Quroborus or tail eating serpent, the symbol of the cyclical nature of the cosmos. In Egyptian medicine we clearly find the snake's most important attribute its dualistic nature the snake that kills is the snake that cures. The Egyptian snake Goddess Meresger could inflict disease on those who offended her yet was invoked to protect against snake bites. Snake amulets in turn could protect against disease. In the very ancient papyrus Ebers the fat of the black snake is found as a part of the materia medica.