Vampires may have been getting at the right idea. Scientists published research Sunday showing that the blood of young mice has a rejuvenating effect on the muscles and brains of older mice. In one experiment, the blood of young mice was found to stimulate stem cells and muscles in older mice, while vice-versa, old blood in young mice prematurely aged them. In another, the young blood gave older mice a stronger sense of smell and led to the growth of neurons. While young blood’s Dorian Gray-like effects have only been shown on mice, there is hope it will be replicated in humans.