Number one, there is such a thing as a skeletal stem cell -- a skeletal stem cell that builds up the entire vertebrate skeleton, bone, cartilage and the fibrous elements of skeleton, just like there's a stem cell in blood, just like there's a stem cell in the nervous system. And two, that maybe that, the degeneration or dysfunction of this stem cell is what's causing osteochondral arthritis, a very common ailment. So really the question was, were we looking for a pill when we should have really been looking for a cell.