In the saga of twilight new moon what was carlisle doing when jasper attacked Bella but didnt mean to and why?

In the book New Moon from the Twilight Saga, it was actually James not Jasper who attacked Bella. As he is hunting her because Bella's smell was irresistable to vampires who could sense it more clearly like James as they have a hunting sense. While the rest of the Cullen vampires, including Carlisle, attempt to locate and warn her.