We have found plenty of bizarre ways to shuffle off our mortal coil. By our own ingenuity alone, we have invented suicide, the knife, the gun, the chainsaw and the hamburger - and throw in the natural killers such as disease, drowning, bear attacks and so on and it is little wonder that colourful tales of death abound.
However few causes of death are as mysterious as Spontaneous Human Combustion. Dismissed as myth by some, scientifically explicable by others and as a visitation of otherwordly moral justice by others, the SHC phenomena flirts with the boundary lines of science, scepticism, folklore and legend.
What seems undeniable is that throughout history, people have been found burned to death in a manner which stretches plausible explanation - perhaps to breaking point. As the phenomena does not officially exist, there is no scientifically accepted categorisation for cases of SHC, but there are typifying features among alleged cases:
The torso of the body is entirely consumed by fire
The extremities - particularly the feet and head - are left untouched
The bones are calcined - that is, reduced to a fine ash, although sometimes they retain their shape until attempts are made to move them
In terms of victims, they are have been reported from all ages and stations in life, but the stereotypical victim is an elderly person, most likely a female and often corpulent or fat.
Taking these broad commonalities into account, many have suggested a 'rational' explanation for reported cases of spontaneous human combustion: the so-called "wick effect."
It is postulated that the victim's clothes are set alight by a source of ignition such as a burning cigarette or naked flame while asleep or unconscious. As the clothes smoulder, subcutaneous fat in the body is rendered by the heat and drawn into the clothes - much as the wax from a candle is drawn into a wick. This keeps a persistent flame burning for a long time without ever attaining a fierce blaze. Thus, the body is burnt over a long period and the extremities survive because of their low fat content.
"It was demonstrated in 1998 on BBC 1's QED programme. A dead pig, which was chosen as pigs have a similar fat content to humans, was wrapped in cloth and set alight. It burned for five hours before the experiment was ended, and the fire largely consumed the pig’s body, including its bones, yet there was little heat damage to other items that had been placed in the room with it."
The account - and the show itself - is compelling. Below is the show, unfortunately dubbed in Russian. From around the 18 minute mark, you can see the demonstration.
For those sceptical of the wick effect, it is worth noting that the beginning of the experiment begins with the blanket in which the pig is wrapped being doused in petrol. I am personally unaware that this is a commonality in cases of alleged SHC.
The wick effect - like many supposedly scientific explanations for other phenomena fails to account for other factors in some ways, however. Some cases are known where witnesses have actually seen the victim catch fire while nowhere near a source of ignition. Other cases are known where the time between the last sighting of a victim and the discovery of their body is simply insufficient for the wick effect to have had time to have come into effect. Lastly, there a handful of survivors who have found themselves alight and been unable to describe anything explicable in terms of ignition.
This, of course, does not rule out the possibility that the theory is true. Other theories advanced as explanations are more outlandish. In Victorian times it was assumed that the victims were alcoholics and that the alcohol was taken into the flesh and rendered combustible.
We now know that that makes no scientific sense, but it fitted into religious and social conventions of the time and served as a useful moral lesson for the temperance movement. We can fairly assume that deaths from SHC were, in earlier times, put down to supernatural forces (indeed, many broadsheet ballads recount tales of people burning to death spontaneously for their sins).
Other suggestions have been ball lightning (a rare and little-understood phenomena in itself), regular lightning, 'kundalini energy' and some as-yet-unknown chemical process within the body itself. It is worth remembering that the body is 80% water, but that water itself is comprised of highly hydrogen and oxygen - hydrogen being highly combustible and oxygen being a necessary part of the 'fire triangle.' If these two elements are somehow separated by electrolysis they can become a highly combustible source of energy.
There is, of course, no known biological process by which this can happen.