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The last word–
THE BEST BITSIn a worst-case scenario, if one had
to eat parts of oneself, which non-
organs would be the most nutritious?
Nails? Hair? Earwax?
Nails and earwax are almost indigestible, unless you pressure-cook them for a long time, preferably in mild acid. If we take nutrition to mean energy or proteins and the like, then bone marrow or fat tissue would be the most rewarding.
Extracting marrow is a tough task, so using liposuction to harvest fat would be best, assuming you had some left to harvest. Fat tissue comprises about one-sixth to one-quarter of the mass of a vigorous person, and over three-quarters of a grossly obese one. But if you harvested too much at a time, the trauma could kill you. Drinking blood would not provide you with very much nutrition.
In truth, there is little nutrition on the typical human body available for non-surgical harvesting. Unlike humans, scavengers like museum beetles and clothes moths can digest
keratin – the protein of hair and fingernails – but about the only significant external item a human could consume would be their epidermis, soaked in water until some of it could be scraped off. This skin would probably be more nutritious if left to decay for a few
days, so that bacteria could render it more cheesily digestible. Bon appétit!Jon Richfield
Somerset West, South Africa
Your body will start to consume itself in a reasonably efficient manner during starvation as fat reserves are used up. When the fat has dwindled the body turns to its muscle tissue.
To surgically remove tissue for consumption would inflict considerable trauma on a body already weakened by starvation. By cutting off bits you would reduce your chances of survival, since the damage to your body would instigate self-repair, which uses up yet more fuel.
Consuming your waste products such as urine would cause further problems. If you must drink urine in a survival situation, distil it first. Consuming contaminated brine when you already have so many problems is not a route to longevity.Bimmo
By email, no address supplied
I hesitate to suggest this, but you have already suggested earwax (of which there would not be enough, even if it were nutritious), and your resistance to grossness may be weakening if you are already drinking your own urine in a bid to avoid dying of thirst. In light of this, might I suggest eating faeces?
Faeces contain lots of good protein because a major component is the dead bodies of a vast number of gut bacteria. It smells bad, but holding your nose makes the taste bearable, apparently. I don’t think eating your own faeces could make you seriously ill, because you can only catch a disease such as hepatitis from the faeces of someone who already has
the disease. Similarly, although there are dangerous strains of Escherichia
coli, if your gut E. coli were dangerous you’d already be sick. To be on the “safe” side, you could cook the faeces until their internal temperature reaches 70 °C to kill off any E. coli.
I would advise getting professional advice before eating faeces, unless your life really does depend on it! And don’t forget to start collecting it before you run out of other food or you might not be producing much.By email, no name or address
supplied
BIGGER BAGWhy, when you pour boiling water
on a tea bag, does the bag inflate?
(Continued)
It’s all to do with the vapour pressure of the water vapour inside the tea bag. At room temperature, the air trapped inside the tea bag might start off with a negligible water content of, say, 1.6 per cent and be at 70 per cent relative humidity. As the boiling water is poured and enters the bag, the temperature rises and the vapour pressure inside the bag increases as water evaporates at the air/water interface. Finally, the saturated water vapour pressure at the new temperature is reached and relative humidity hits 100 per cent. For example, at 95 °C the gas inside the bag would be about 85 per cent water vapour and just 15 per cent air – assuming no air escapes the bag – since the vapour is far less dense than air. This puffs up the gas in the bag to about 5.5 times its original volume: the saturated vapour pressure of the water amounts
to around 0.85 atmospheres, while the air makes up the remaining 0.15 atmospheres. There would also be a 25 per cent increase in volume as described by Charles’s law, as previous correspondents have noted. The increase in gas volume fully inflates the bag.Chris Terry
Teddington, Middlesex, UK
THIS WEEK’S QUESTIONSBeat generation
Most music is written in 4/4 meter, giving four beats per bar. Why we are inclined to prefer 4/4 time? Are there circuits in our brains that tick along in patterns of four?Michael Light
Carlisle, Western Australia
On the tube
I saw what looked like a huge tube of cloud floating just below a uniform blanket above rural Oxfordshire, UK, at 7.30 am on 11 December 2007 (see Photo). Anyone know why it formed?Shuvra Mahmud
UK
“There is pretty little nutrition
on the typical human body
to harvest non-surgically”
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