The dream of rejuvenating the aged by the infusion of young blood is much older than anyone living. It is said that the Scythians thought to make themselves strong by drinking the blood of their enemies killed in battle. And Dracula kept himself youthful by drinking the blood first of young maidens visiting Transylvania and later of maidens in England once he had moved there.
Blood is not the only tissue that has been thought to protect and rejuvenate the elderly. In the 1920s a Franco-Russian surgeon named Serge Voronoff transplanted monkey testes into men (some of them eminent, for example Kemal Ataturk) whose virility had declined, and claimed that it worked. He made a fortune but soon became the object of mockery and scorn, dying in prosperous obscurity in Switzerland in 1951.
There is always an air of charlatanry about those who claim to be able to turn the biological clock back (it is easy to find smooth-talking promoters of recaptured youth on the internet, for example), but a recent article in the New England Journal of Medicine suggests that some of the old ideas about the rejuvenating qualities of young blood may not have been quite so far-fetched after all. It is early days to proclaim that eternal youth is around the corner, and personally I am not sure I would want it even if it were, but according to the author a technique known as heterochronic parabiosis has retarded or reversed the aging process in mice. It is, of course, some distance from Mouse to Man.