Few years ago I held the hand that had servedwith the paints he used to create his greatest masterpieces.
I was at the 121st birthday party of Madame Jeanne Calment, officially the oldest person who has ever lived. When she was a teenager, she had worked in her father's shop inin the .
The day may soon come when death is no longer inevitable, says Desmond Morris
Vincent came in to buy his paints, but she wasn't that keen to serve him, she said, because "he was ugly as sin, had a vile temper and smelled of booze".
Yet, as a dutiful daughter, she had taken his money and handed him the paints with which he would create Sunflowers and many of his other most famous works.
I was attending her birthday because I wanted to understand how any human being could survive for such a long time. Her answer was that it was due to her calmness.
"That's why they call me Calment," she chuckled, with a twinkle in her now almost sightless eyes. But there was much more to it than that. I discovered from her doctor that, amazingly, she had never had a day's illness in her entire life.
What an immune system she must have had! It had protected her against every virus going. If only medical science could have extracted its essence and injected it into the rest of us.
In addition to being genetically blessed with this extraordinary defence mechanism, she had also, by her nature, retained a cheerful outlook on life and an irrepressible sense of humour.
She was particularly amused that, aged 120, she had made her first music record, a funk-rap number called Mistress Of Time.
In these health-conscious days of carefully balanced diets, fitness regimes and workouts, it is worth asking what kind of lifestyle the astonishing Madame Calment had enjoyed for so long.
The answer comes as a shock. It turns out that she was a gourmet who liked alcohol, cigarettes, chocolates and sweets.
As well as her sweet tooth, she was fond of cheap red wine, fois gras and a rich local stew.
When she reached the age of 117, doctors advised her to give up drinking port and they tried to stop her smoking.
Somehow she managed to fool them and was caught by a photographer puffing away on a cigarette the following year.
I argued with her doctor that it was mean to start interfering with her small pleasures, which had obviously stood her in good stead.
He replied that he wasn't forcing her to stop drinking, merely trying to persuade her - now that she was a national treasure - to drink a more expensive, better red wine.
Jeanne Calment died the year after that party (perhaps missing that rough red wine she had enjoyed for so long). And though I never saw her after that initial meeting, I think of her often - especially now that I am into that part of the human lifespan which my friend and fellow octogenarian Sir David Attenborough laughingly calls "injury time".
It's not that I confront my own mortality with dread. It's simply that as the indignities of the ageing process become harder to deny, I find myself wondering about the best means of adjusting to that reality.
A quarter of a century ago, I wrote a book about the ageing process. Now that I am 80 years old, I regret havingbwritten that book because I know too much about the physical decline of the human body as the years pass.
Like other animals, we have a built-in obsolescence. As we grow old, the efficiency of cell-replacement declines and our bodies become weaker until eventually something comes along to which we no longer have sufficient resistance, and we die.
There is nothing mysterious about death, it is simply a way of keeping each species genetically flexible. Each of us is a temporary container for our immortal genes.
We come to an end, but they go marching on - through our children - and, in the process, each generation sees a mixing of the genes that keeps offering new possibilities and enables our species to adapt to changing conditions.
Sadly, this system works only if we as individuals are discarded after we have bred and reared our offspring. Or, as the saying goes: "Nature with its frugal eye asks only that we mate and die."
We all have to face this, but it would be preferable if there were a system in which we remained strong all our lives and then dropped dead, rather than slowly wearing out. What is worse, the wearing out process is uneven.
With some of us, the brain goes first. The last time I sawher body looked in good shape, but she had no idea where she was or what year it was.
With others, the body goes into decline, but the brain stays sharp and bitterly resents the fact it can no longer command the limbs to sprint or climb.
I belong to this second category. My body is beginning to creak, but I am still working until 3am or 4am every night. Brain cells hate being idle. It is a case of: "If you don't use it, you lose it."
If you stop challenging yourself, your mental processes decay rapidly. The very concept of "retirement" is lethal.
Society should find other forms of occupation for its older members - not trivial hobbies, but serious challenges that require experience and ingenuity. Facing them would keep the brain from rusting.
But if society should change its attitudes to ageing, then so too should individuals. And there are important lessons here that can be learned from people like Madame Calment.
The first and most important one is that she had outlived everyone else on the planet by not worrying about her health.
Until the doctors got at her, in her final years, I doubt if she ever gave her health a moment's thought.
She ate the rich food she liked, she drank the cheap wine she liked, she smoked the strong cigarettes she liked and - as she said - she kept calm.
Had she worried about her health and taken steps to improve it, the anxiety caused by stirring up fears about ill-health would themselves have reduced the efficiency of her immune system.
She would have then probably succumbed to the afflictions that plague so many people.
Another important point is that she didn't do any extreme exercise, but she did take a lot of the milder type. She was still riding her bicycle at the age of 100.
When I made a study of the lifestyles of people who lived to be 100 and over, I found this applied to most of them.
They nearly all had a regular, mild form of body activity that kept them moving. Cycling, walking and gardening were three of the most popular - done not to keep fit but for pleasure.
And, like Madame Calment, they almost all retained a wry sense of humour and cheerfulness.
Surprisingly, among the very old, Jeanne Calment was not alone in her love of cigarettes.
The actresswas still smoking 60 a day aged 100; a woman named Edith Beck gave up smoking on her 103rd birthday because she felt it was time to start looking after her health and promptly died.
It seems horribly unfair, but there appears to be a gene that protects certain individuals from the ravages of smoke-filled lungs.
They also enjoy their food and drink. When she was 100, Estelle was drinking sherry and regularly dining out.
Katherine Plunket, who lived to be 111, enjoyed feasting on game and always tucked in to turkey, plum pudding and champagne on her many birthdays.
The oldest man who ever lived, Mr Izumi of(who made it to 120), enjoyed his daily saki (rice wine) and said his secret was "not worrying".
Eubie Blake, a U.S. jazz pianist, said at his 100th birthday party: "If I'd known I was gonna live this long, I'd have taken better care of myself."
The irony is that it was probably his not worrying about his health that enabled him to live that long.
It seems that if you wish to live an unusually long life, you need to eat and drink what you fancy, keep as mobile as possible, have a lively interest in the world around you, avoid introspection and, above all, do not waste time worrying about your health.
Food faddists, couch potatoes, solemnand health fanatics all seem doomed to earlier graves. Studying the over-100s, it seems advisable to avoid intensive health regimes.
I often look at the faces of joggers as they go past to see whether they are happy joggers or miserable joggers.
Happy joggers - enjoying a gentle pace and the pleasure of getting out from behind a desk - are on the right track. They are keeping mobile without becoming anxious.
They would be better off (at least their knees would be) if they went for long walks, but they at least come into the "regularly mobile" category that seems to go with long life-spans.
By contrast, those joggers who stumble past with agonised faces, saying to themselves "Gotta get fit, gotta get fit", are probably reducing their chances of a long life.
The couch potato goes to the other extreme. The secret is moderation.
Another source of health-destroying anxiety is food faddism. Diets that are supposed to make you live longer are forever being offered to the gullible by the cynical.
Every day, we are told that we should eat more of this or less of that.
Then, later on, we are told that, sorry, it is the other way around: you should eat less of this and more of that. What is good for you today will be bad for you tomorrow.
There are three truths concerning human feeding behaviour.
The first recognises that we evolved as omnivores, succeeding where others failed because we consumed a wide range of foods.
One of the reasons we are now living longer than we did in the past is that the shelves of supermarkets display a truly astonishing variety of food from all over the world.
The second truth, which renders all diet books superfluous, is that the more you eat, the fatter you get, and the less you eat, the thinner you get. End of story.
But whether you are eating more in order to put on weight or eating less in order to lose it, it is always important to keep the range of foodstuffs as wide as possible.
The final food truth is that you should enjoy what you eat and take time to relax while eating it. Speed and anxiety ruin digestion.
It really does seem that if you eat, drink and are merry, you have a good chance of not only having an enjoyable life, but a long one too.
But there may, one day, be an even more efficient way of improving your odds against the Grim Reaper. Despite the old saying about death and taxes, there is nothing inevitable about death.
If we could find a way of genetically interfering with the biological imperative that instructs our cell replacement to become increasingly inefficient we could, in theory, live for ever - as long as we are not knocked down by a No74 bus.
If such a discovery were made, it would create a population explosion that would make our currentlook like a trifling matter.
Eventually, there would have to be a breeding licence that permitted a new birth only when a lethal accident had occurred.
It is unlikely genetic manipulations will have advanced enough to enable us to cheat death in the near future - and certainly not in my lifetime.
The point I am making is not that it may happen, but that it could do.
The advance of medicine is so rapid that things that may seem fantastical today could be commonplace within a few decades.
While it is impossible to say how some future discovery may impact on those being born into the world now, it is safe to assume people like Madame Calment will be much more usual in the not-too-distant future.
Two years ago, in the glaring sun of the Namib Desert, I suddenly noticed that I was the only person not wearing sunglasses.
The lenses of my eyes had darkened with age. So when I returned home I had surgery to replace the old, discoloured lenses with artificial ones.
I now have the eyes of a teenager again - the world is bright and beautiful once more.
Returning for a check-up, I asked the eye surgeon who had given me my new eyes if, perhaps, he could manage a whole-body transplant.
If only I could have my brain inserted into the skull of a healthy young man who had died of brain damage, but who, in all other respects, was in good order, I could start all over again and enjoy another spell of life on this fascinating little planet of ours.
My surgeon grinned: "Not yet." No, not yet. But maybe one day.