You *can* cure Deadly Poison with just 60 Healing AND 60 Anatomy. Although one's chances are relatively low. The higher the better.
Edit: I found it best to have a base of 100.0 Healing and Anatomy and then use enhanced bandages to be as though 110 Healing. I still failed on occasion so I decided it best to keep working the skill and my goal was to get to 120 Healing, 120 Anatomy, base.