Bolt in the neck, outstretched arms and a short lurch from the lightning rod towards the nearby village, Frankenstein's monster has become a fixture in modern horror. Mary Shelley wrote her novel about the reanimated man when galvanism was in vogue, but the concept hasn't died in the many years since her story was printed.
All this begs two questions: how realistic is the concept of a walking corpse, and could dead flesh be reanimated using scientific techniques? Let's explore...
Galvani and His Electric Frogs
- Galvani and His Electric Frogs
- No Movement Without Energy
- Infection and Rejection
- Applied Necrobotics
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| If we made a walking corpse, would we be able to control it? (maraisea) |
Galvani and His Electric Frogs
In 18th-century Italy, Luigi Galvani discovered that the severed leg of a frog would twitch when exposed to an electrical current. Based on this, he suggested that all animals possessed an innate electricity that animated their movements. His contemporary Alessandro Volta disagreed, arguing that the legs were merely conducting (and reacting to) electricity from an outside source - Volta was mostly correct, as it turns out.
The experiments of the two dueling scholars established that electricity could cause muscles to contract, generating movement. Giovanni Aldini followed on from his uncle Galvani's work with ghoulish public demonstrations of electrical stimulation using the corpses of human criminals, causing them to twitch and even raise limbs to the sky.
Modern biology has revealed the electrochemical nature of the human nervous system - along with how we use it to stimulate our muscles. Whilst difficult, it would not be impossible to generate coordinated movement in a human corpse via electrodes.*The experiments of the two dueling scholars established that electricity could cause muscles to contract, generating movement. Giovanni Aldini followed on from his uncle Galvani's work with ghoulish public demonstrations of electrical stimulation using the corpses of human criminals, causing them to twitch and even raise limbs to the sky.
In theory one could replace the nervous system with a network of wires, conducting electrical impulses to the muscles and stimulating contraction in dead cells. However, movement would only be possible for a short time without a source of chemical energy.
*Before you ask, head or brain transplants have their own problems... even before having to deal with oxygen deprivation, infection or tissue rejection!
No Movement Without Energy
Like all living creatures, humans need to consume and respire (i.e., eat, drink and breathe) to survive. Our digestive system breaks down what we eat into components such as glucose, even as our circulatory system brings oxygen to our cells. The glucose is converted into the ATP (adenosine triphosphate) which powers our muscles. Without this chemical fuel, our muscles can't function and our body cannot move - no matter how strong an electrical current is applied.To maintain movement in "dead" tissue without the benefit of a living circulatory system, you'd need an external way of saturating the body with glucose. Probably the easiest way of doing so would be to co-opt the existing blood vessels, pumping them full of a glucose solution. This assumes that the biological processes that convert glucose to ATP are still functioning in the "dead" cells - so they would need to be reasonably fresh and in good repair.
The cells of the human body can actually still function without oxygen, but they produce lactic acid when doing so - leading to pain and (in extreme cases) acidified blood. That wouldn't be much good for long-term use!
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| It turns out that you can't just jigsaw body parts together and hope they work... (Olga Kononenko) |
Infection and Rejection
If one were to attempt to bring a corpse back to functionality, damaged organs and bones would need to be repaired - or even replaced. Implanting donor organs, wires or mechanical devices carries a new set of problems, depending on whether the immune system is intact or absent.If the immune system is absent you'd have nothing to stop bacteria or fungi from settling into the dead tissue, especially with a large amount of surgical scars that could be sites for infection. You'd end up with musculature being broken down by microorganisms, and little that you could do about it - saturating the body with disinfectants and fungicides would probably be your only option.
If the immune system of the prospective creation was still functioning somehow, any organ transplant would likely be rejected - the immune system would recognize the donor organ as a foreign object (typically due to the DNA not matching) and attempt to destroy it (this can still happen with metallic implants, though far less often.) To get around this, you'd need to dose your creation with immuno-suppressant drugs - but this would leave similar risks to lacking an immune system altogether.
A further factor is the damage that occurs to a body during everyday life - every bump and scrape damages cells, and a living body is in a state of constant regrowth. Dead tissue would lack this repair process and both the muscles and organs would slowly break down. You'd need to replace damaged parts regularly to keep the body viable, with every transplant carrying risks of rejection or infection.
Applied Necrobotics
So perhaps reanimating a human cadaver is currently beyond us, but the field isn't a complete dead end. Some researchers have actually begun looking into using animal parts as mechanical devices. By using the intact corpse of a spider, researchers were able to fashion a pneumatically actuated gripper.Spiders use hydraulic pressure to extend their limbs rather than the extensor muscles of most animals, and their limbs naturally "grasp" when at rest. By inserting and sealing the needle of a hypodermic syringe into the cadaver of a spider, researchers were able to change the pressure inside the corpse and cause the limbs to "release" by injecting air.
As ghoulish as this may seem, there are advantages to using this method in place of the traditional production of actuators. They are much faster to make, last a reasonable amount of time (700 uses were reported before evidence of degradation occurred) and naturally biodegrade when disposed of!
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