The fabled fountain of youth may finally be at hand. A bold prediction perhaps, but scientists at Harvard University have been using the blood of younger mice to give older mice renewed vigor. On average, the older mice recovered more grip strength and more endurance on a tread mill than untreated mice. The research also showed mice treated with younger mice blood produced more blood vessels and had more blood flow to the brain. The scientists are hoping that some of their findings could lead to a way to treat age-related mental decline and perhaps dementia. The findings are in the journals Nature, Medicine and Science.