Lie back and think of living for ever

A drug has been found that seems to slow down the ageing process - in certain creatures at least. Is immortality for man just around the corner, courtesy of researchers in California, Atlanta and Manchester, and of the nematode worms they have tried the drug out on? The Elixir of Life? The Secret of Eternal Youth?

A drug has been found that seems to slow down the ageing process - in certain creatures at least. Is immortality for man just around the corner, courtesy of researchers in California, Atlanta and Manchester, and of the nematode worms they have tried the drug out on? The Elixir of Life? The Secret of Eternal Youth?

It is a secret that has been sought for ages: the Greeks had Tithonus asking the goddess Aurora for the gift of eternal life. She granted it. It was a mistake. He had to live forever, growing always older and weaker and smaller. He ended up a grasshopper, impotently chirruping away. He should have asked her for eternal youth instead.

Dean Swift, in Gulliver's Travels, used the same idea for his Struldbrugs, a race of wretched immortals who became more and more decrepit and infirm and stupid and who had to be cared for - forever - by their youngers and betters.

Aldous Huxley wrote of a millionaire who takes advantage of a medical discovery to prolong his life; by his 200th birthday he has become nothing more than a gibbering ape.

The moral of all this is that writers have scarcely considered longevity to be an unadulterated boon. Scientists and the rest of us still make Tithonus' mistake of confusing eternal life with eternal youth.

Dr Alec Bürkle, a lecturer at the Institute of Health of the Elderly in Newcastle, where the ageing process is researched, says: "It is very difficult to measure the youthfulness or agedness of a nematode worm; all you can really do is measure how long it lives. So we cannot really say whether the latest experiments have given the worms a longer youth - or just extended their decrepit old age."

Is any development from this nematode drug ever likely to make the human life-span longer?

Dr Bürkle advises extreme caution. "Nematodes are very simple things. I like to think that human beings are much more complicated than worms. We have a dozen or more different cell types; the worm has only one. Our ageing process stems from lots of factors. Different organs age in different ways, no one of them decisive or dominant.

"But that said, the result is extremely interesting. The drug they have given the worm mops up chemicals called free radicals in their bodies. The experiment shows quite definitely that free radicals are involved in part, at least, of the ageing process."

Assume the most optimistic possible scenario: that some development of this drug works for humans and extends the younger, vigorous, more active parts of our lives. Would a nation of perpetually energetic young-at-hearts be an improvement or a disaster?

In her classic book A Distant Mirror, the historian Barbara Tuchman describes just such a world - a real one. In 14th-century Europe, lifespans were so short most citizens and almost all of their rulers were barely out of their teens. The kings displayed all the balance and judgement - and probably the acne - of your average teenage boy racer today. The result was a calamitous century of war, famine, bad judgement and perfectly dreadful government in which everything that could go wrong did.

Shangri-La, James Hilton's fictional Himalayan valley of eternal youth, was perfect - but so boring people preferred the horrors of instant old age, which struck them the moment they left.

These dreadful warnings have not deterred the optimistic - or the desperate. Thousands have joined in the somewhat frightening real-life attempts to find eternal - or at least extended - youth.

Serge Voronoff, in France in the 1920s, tried to extend the sex-lives of millionaires by transplanting into them the testicles of executed criminals - and when that limited supply dried up, he gave them chimpanzee scrota instead. Hundreds queued for his gruesome monkey-gland treatment, and swore that it rejuvenated them. Dogs and, oddly enough, even guinea-pigs also provided donor organs. "If only youth knew; if only age could..." as Henri Estienne put it in 1594. Viagra has suddenly meant that age now can; and chimps and guinea-pigs can feel a lot more secure.

Other life-extending theories and substances abound. A chemical found in cornflakes has been held to make mice live longer. There is a man in America who has been half-starving himself for years, in the belief it will make him live longer. The calorific restriction theory almost seems to have some validity. "Experiments have definitely shown that rodents gain enormously in lifespan if you restrict their foods - to the undernourishment stage rather than malnourishment," says Dr Bürkle. "Experiments are going on now to see if it works with monkeys. But they have a longer life-span anyway, so it will be 20 years before the experiments can show a result."

And, oddly, there is a connection with the worms here. "The nematode drug absorbs free radicals; and calorie restriction makes the body produce fewer free radicals in the first place. The same principle seems to be at work. But calorie restriction tackles the ageing process one stage nearer its root."

And if we ever reach that root, and make people live to a 150 years or more, what follows? Well, the change will be as fundamental as the one we have lived through already. What we have now is not a natural state of affairs. Evolution never designed us to grow old. "There is no evolutionary pressure to encourage us to live long," says Dr Bürkle. "A mouse which was capable of living to 100 would probably still get eaten by a cat before its first birthday; so genes for longevity would be of no practical use to it at all. It would be much better off with genes that give it longer legs to help it escape from the cat."

It is only in the last two centuries that similar constraints on longevity have been removed from humans. We have already just about doubled the average human lifespan. Life expectancy has increased from 40 years in the 15th century - the same as in ancient Athens - to 75 years today. The over-80s, who make up six per cent of our society, are a new phenomenon. When centenarians or 120-year-olds make up a similar six per cent - what then? Will they take up room and resources needed for others? Are we heading for too crowded a world, a planet wedged tight with wrinklies? Will those long-livers be defrauding the younger generation of their right to air and space and freedom? All they will do is chug round their golf-courses on their electric buggies, bored rigid, no doubt, because they have been everywhere and seen everything and been round that golf- course a million times already, but just are refusing to move over and die. Parts of the retirement coast of Florida are already horribly like that.

Dr Bürkle says: "Would living longer mean simply that we live a longer old age, endure a longer geriatric time of illness - the suffering part of life?

"Or can we instead increase not the lifespan but the health-span, the active, contributing part of life? I would actually reckon my professional life well spent if I were able to reduce the ravages of just one of the afflictions of old age - Alzheimer's, arthritis, cancer - rather than make anyone live any longer. That seems to me to be the better goal."

The alternative is rather too awful to think of.