Why is the ring finger sometimes called...

For centuries, it was believed that the ring finger had a nerve that connected it to the heart. The Romans and Greeks used this finger for stirring mixtures, especially in alchemy, in the belief that anything noxious would be immediately detected by the heart, which would produce some warning sign. This connection, which years later was proved false, was also why the finger was chosen for rings, marking the heart’s sentiment. English superstition still holds that the ring finger should be used for applying ointments or salves or for scratching the skin.