"Greek Lekythos (vessel for oil) showing Ladon, the reptile protector of the Garden of Hesperides being fed milk by a nymph", 340 BC Getty Museum, Los Angeles, California , USA

The Ladon serpent protected the mythical tree of golden apples (venerated emblem of Venus). The golden apples of health and immortality were plundered once mortal Hercules killed Ladon during his 12th labor.

 

This image brings to mind human relationships with the tree of knowledge and human nature. After Eve ate from the tree of knowledge, human paradise ended because what Eve did would let humans use knowledge to promote Evil. When an aspiring physician takes the  Hippocratic Oath, he pledges to never use medical knowledge for doing evil (including exploiting patients for self-gain).