HAVE YOU EVER fancied leaving your body for medical research? Quite a lot of people are taken by this philanthropic idea. But leaving your mortal remains to medical science will not necessarily work out in the way you might expect.

Most men and women who decide to will their bodies 'for research' have the notion that their corpses will be used to further scientific knowledge about a particular disease.

They often think there is a big research centre somewhere working on a cure for, say, cancer. They might reasonably surmise that soon after they expire, a scientist will come rushing into this centre of excellence and say: 'Great news, Professor Robinson] Someone has left us a cadaver for research]'

Alas, it is not like that at all.

The truth is that if you leave your body to science, it will almost certainly be used by medical students for dissection. This will be a thoroughly worthy function, since the doctors of tomorrow have to learn their anatomy somehow, but it is not quite what the average punter envisages when he makes the Grand Gesture in his last will and testament.

Furthermore, the process of dissection by medical students is not exactly the nicest thing in the world. This is what happens.

Most medical students spend their first five college terms dissecting their way through the human being, so that - with a bit of luck - they then know where every important muscle, nerve vein and artery is located. Naturally, they have to have bodies for this purpose. As a result of the early 19th-century unpleasantness in Edinburgh when Messrs Burke and Hare dug up Scottish citizens to flog their cadavers to the medical school, the goverment brought in the Anatomy Act, to ensure an adequate supply of decently obtained corpses.

There are two kinds of 'decently obtained' corpse: those that have been bequeathed by their owners to medical science, and the bodies of paupers. Yes, sadly, there are some people who die so poor that their bodies end up going to a college anatomy department for dissection; in return, the college pays for their eventual funeral.

For both types of cadaver, the process of dissection is very long, and extremely destructive. If your Aunt Edna wants to leave her body for this purpose, it might be as well to warn her that she will finish up looking like the last remnants of a Christmas turkey.

The 'subjects' for dissection are normally laid out in rows on glass-topped or metal tables. They are, of course, naked. Indeed, when I first walked into a dissection room as a young man just out of the sixth form, it was their nakedness that shocked me most.

Medical students sit round the tables, often with three young men or women allocated to one arm or one leg for a term. Medics usually have a little canvas roll of dissecting instruments - the most important of which is a very sharp knife. And it needs to be sharp, because the 'pickling' process that the bodies have undergone before coming into the dissection room makes skin as tough as old boots. I still have painful memories of my feelings of revulsion when I first tried to hack through that hard, leathery skin to expose the squishy yellow fat underneath.

I am afraid the skin of the 'subjects' is soon removed, along with the fat and all sorts of other bits that are not of very much relevance to the studies of future doctors. As the weeks go by, more and more of the poor old corpse has to be sliced out in order to expose the internal structures. In the end, most of the body has been cut away, apart from the bones.

So what happens to all those chopped-off bits? At my own medical school, I regret to have to tell you that the procedure for their disposal was pretty ghastly. At the end of each day's dissections these 'scraps' were simply swept away into a sort of communal fleshpot in another room, where the soft parts of about 24 different people were stored for some months all mixed up together.

When we had finished our five terms of dissection, the funeral arrangements for the unfortunate departed were really quite bizarre. Although a more-or-less intact skeleton was placed in each coffin, what went in with it was a random selection of material from the half-ton bin of fleshy bits. In other words, the burial casket with a name on it contained the right bones - plus an assortment of chopped-up muscles, skin and internal organs from the other two dozen former inhabitants of the dissection room. It struck me as the ultimate in togetherness.

Nowadays, so I am told by an anatomist friend, things are more specific. There is a labelled 'spare parts can' for each subject so, in theory, all your bits should get buried in your own coffin.

The simplest way of initiating such an arrangement, should you still be considering it, is to write to Her Majesty's Inspector of Anatomy at the Department of Health, Wellington House, 133-155, Waterloo Road, London, SE1 8UG, indicating your desire to be 'anatomised'. In Scotland, write to the Scottish Home & Health Department at St Andrew's House, Edinburgh, EH1 3DE. The Inspector will probably put you in touch with the professor of anatomy at your nearest medical school.

When your death occurs, your next-of-kin should immediately contact that medical school, or telephone the HM Inspector on 071-972 4550.

But be warned: it is a good idea to talk the whole idea over with your relatives before you make your decision to bequeath your body. They may not be quite so keen on the idea of dissection as you are.

The author is a doctor, broadcaster and elected member of the General Medical Council.