Research in mice seems to suggest it can THE vampire jokes write themselves. In the past few years a steady trickle of scientific papers has suggested something straight out of an airport horror novel: that the blood of young animals, infused into the old, has rejuvenating effects. Scientists are excited enough that at least two clinical trials are currently running in humans. But is it true? And if it is, how does it work? The answer to the first question seems to be a qualified yes, at least in animals. The rejuvenating effects are seen when lab mice are joined together in a rather gruesome procedure called parabiosis. That involves making cuts in the skin of two animals, then suturing them together at the site of the wound. As the cuts heal, the pair’s blood vessels will grow together and…