Exploration of the biochemistry of regeneration in lower animals is turning up interesting new information. From Nature: "Researchers have known for decades that an electrical current is created at the site of regenerating limbs. Furthermore, applying an external current speeds up the regeneration process, and drugs that block the current prevent regeneration. The electrical signals help to tell cells what type to grow into, how fast to grow, and where to position themselves in the new limb. ... the complex networks needed to construct a complicated organ or appendage are already genetically encoded in all of our cells - we needed them to develop those organs in the first place. ... The question is: how do you turn them back on? When you know the language that these cells use to tell each other what to do, you're a short step away from getting them to do that after an injury. ... The simplicity of the regeneration start signal is promising ... it is just possible that a properly tuned electric signal is all humans need to jumpstart tissue regeneration."