Near the Western Thalmont Node (the second place you meet Kira), you can find a location called Ram's Cave. Inside the cave are ten Thuloks, four Demons, and six or more treasure chests. The chests have some treasure, but the target of interest is the ten Headless Hearts from the Thuloks you kill. Each will net you 74 Vitality, if your Alchemy is at level 10 or higher.