The idea of pulling together a human from parts of other humans is nothing new. Perhaps the most famous example in literature is the imaginings of Mary Shelley in her novel "Frankenstein" (1818). As you probably remember, in this tale a scientist named Frankenstein assembles a monster from different parts of graveyard corpses and gives it life in the laboratory. Outside the pages of fiction, scientists have experimented quite a bit with assemblages of animals. Let's look at a few examples involving head transplants.
In 1954, Russian doctor Vladimir Demikhov performed a series of experimental operations creating two-headed dogs. He successfully grafted the head and forelegs of one dog onto the neck of another. Amazingly, both heads could see, hear, smell and swallow. The longest any one of his experimental animals lived was 29 days. By modern standards, such an experiment seems cruel and unnecessary; however, Demikhov was motivated by his sincere interest in saving human lives. He hoped to gather all he learned from the dog experiments and apply it to human transplants.
At the time, only bone, blood vessels and corneas had been successfully transplanted in humans. Transplants on larger organs like kidneys were attempted, but the organs were always rejected. Demikhov and his team had their sights set on creating a tissue bank with a storehouse of organs to be used any time someone was in need of a transplant.
Fast-forward to 1970 in the United States where head transplant experiments were attempted with rhesus monkeys. Dr. Robert White in Cleveland was able to perform a head transplant where the monkey survived neurologically intact for 36 hours, although it could not move. After nine days, the head was rejected by the monkey's immune system, and the animal died. The largest obstacle cited by the transplant team was the inability to connect the spinal cord.
Since then, experiments have continued in China with mice, and some progress has been made in the understanding of spinal cord connection. And while nothing has been tried yet with humans, an Italian surgeon and member of a think tank devoted to the advancement of brain stimulation named Sergio Canavero is convinced he has a method to transplant a human head that will work and is gearing up to try it out.