A tour of London's many medical museums may not be for the squeamish, but Ian Collins sees a brilliant way of counting our healthy blessings. Personally I wouldn't be seen dead at the ghoulish Bodies display in Earls Court.

A tour of London's many medical museums may not be for the squeamish, but Ian Collins sees a brilliant way of counting our healthy blessings.

Personally I wouldn't be seen dead at the ghoulish Bodies display in Earls Court. Pickled cadavers, foetuses and sundry organs add up for me to a truly offal entertainment. It's the product of sick minds.

But here's a stirring statistic for hyper tourists and hypochondriacs alike. London now has no fewer than 21 museums devoted to health and medicine.

For all the failings of the NHS, an ongoing evolution in care for our physical and mental ills is a modern miracle. Pain and suffering, though far from eradicated, are now infinitely reduced through advances in medical science.

All the more reason, then, for studying the past and giving thanks for the present.

Diaries from days of yore and gore can make for gruesome reading. Celebrated Londoner Samuel Pepys was very lucky when young to survive an operation to remove a stone from his bladder - although he could afford a reputable surgeon, his saviour lost every single patient the following year due to infected instruments.

Norfolk's Fanny Burney, who at one point was almost within shrieking distance of the Battle of Waterloo, could be driven to hysteria by the smallest piece of annoyance. And yet she recorded the amputation of a cancerous breast without anaesthetic - and without flinching.

Until rather recently hospitals were houses of horror, where people simply retired to die after torture sessions from hack medics. Herbs and leeches may now be seen as sensible treatments, but the bad old habit of bleeding made for kill not cure.

Hidden in the roof of a church, the Old Operating Theatre (9a St Thomas's Street, SE1; 020 7188 2679; www.thegarret.org.uk; admission charge; Tube: London Bridge) is a 300-year-old garret used to prepare medicinal herbs and housing our only surviving 19th-century operating theatre. It has now reopened following a revamp.

When public executions were popular entertainments, spectators came here to watch operations performed on a wooden table without anaesthetic or antiseptics. Imagine.

Far more calming is the Anaesthesia Heritage Centre (21 Portland Place, W1; 020 7631 8806; www.aagbi.org; free entry by appointment; Tube: Oxford Circus), with its 2000 objects relating the history of assisted sleep from a blessed breakthrough in 1774.

Life's a gas over at the British Dental Museum (64 Wimpole Street, W1; 020 7935 0875; www.bda.org/museum; free entry by appointment; Tube: Baker Street). See the first clockwork drill, sponge toothbrush, royal dentures and then faint at the spectacle of antique extraction tools. Recover in time to thank the lords of science for the disappearance of marketplace toothdrawers with their awesome muscles and awful pliers.

Talking of spectacles, the British Optical Association Museum - or MusEYEum - geddit? - makes for a visual treat.

In fact, free specialist museums for several royal societies and colleges can be visited by appointment: surgeons (35-43 Lincoln's Inn Fields, WC2; 020 7869 6560; www.rcseng.ac.uk/museums; Tube: Holborn), physicians (11 St Andrews Place, NW1; 020 7224 1539; www.rcplondon.ac.uk/heritage; Tube: Warren Street), optometrists (42 Craven Street, WC2; 020 7766 4353; www.college-optometrists.org/museum; Tube: Embankment) and pharmaceutical (1 Lambeth High Street, SE1; 020 7572 2210; www.rpsgb.org/museum; Tube: Lambeth North).

And then there are free museums at the linked hospitals of the Royal London (Newark Street, E1; Tube: Whitechapel) and Bart's (North Wing, West Smithfield, EC1; Tube: Barbican). The former, serving the East End and once Britain's largest voluntary hospital, includes relics of Norfolk nurse Edith Cavell and Elephant Man Joseph Merrick. The latter relates a splendid history from 1123, with spectacular paintings by William Hogarth.

St Thomas' Hospital, on the Lambeth side of Westminster Bridge, has the Florence Nightingale Museum which celebrates the pioneer of nursing reform not only for her work in the Crimean War, but also for her ideas of hospital design, reform of Indian public health, introduction of health visiting, district nursing experiments and the founding of the Nightingale Training School. (020 7620 0374; www.florence-nightingale.co.uk; admission charge; Tube: Westminster.)

St Mary's Hospital, Paddington charges for appointments to visit its Alexander Fleming Laboratory Museum (020 7886 6528; www.st-marys.nhs.uk/about/fleming_museum.htm). But oh the joy of seeing the reconstructed lab where the discovery of penicillin, in 1928, rescued us from agony.

Naturally the Science Museum (Tube: South Kensington) is a must for those eager to examine the history of human health, especially since the donation of the 100,000-item Wellcome Collection 30 years ago and the more recent scrapping of admission charges. The Wellcome Trust reopens its celebrated library at 210 Euston Road, NW1 next year.

But when you next have time to spare at Liverpool Street station make an appointment to see the free British Red Cross Museum and Archives display at 44 Moorfields (020 7877 7058; www.redcross.org.uk) relating humanitarian service in peace and war since 1870.

Nearby Clerkenwell holds the free Museum of the Order of St John at the base from which warrior monks of the Middle Ages set out to fight for the faith and tend the sick - principally those injured by the fight for the faith. Victorian pioneers began a first aid movement here which continues to offer balm and bandages. (St John's Gate, EC1; 020 7324 4070; www.sja.org.uk/museum; Tube: Farringdon).

The hall of the Worshipful Society of Apothecaries, incorporated as a City Livery Company in 1617, offers a free trove of archives and artefacts charting the manufacture and retailing of drugs at the Blackfriars site from 1671 (Black Friars Lane, EC4; 020 7236 1189; www.apothecaries.org).

Better still, the society of apothecaries founded the Chelsea Physic Garden in 1673, which remains a paradise filled with health-promoting plants in Royal Hospital Road SW3. Open, with admission charges, on Wednesday and Sunday afternoons from April to October. Also a must for those devoted to the therapeutic properties of two plants in particular: coffee and tea.

One of the most poignant places in London is the Foundling Museum (40 Brunswick Square, WC1; 020 7841 3600; www.foundlingmuseum.org.uk; admission charge; Tube: Russell Square), telling the saga of London's first home for abandoned infants and honouring patrons such as Hogarth and Handel.

More uplifting is the Museum of Great Ormond Street Hospital for Children (opposite the hospital; free appointments on 020 7405 9200 ext 5900; Tube: Russell Square). Founded in 1852, the internationally-acclaimed centre continues to receive the royalties of J.M. Barrie's Peter Pan.

If this tour through (ill)health down the ages has left you a tad depressed head for Hampstead and a viewing of the most famous couch in medical history, courtesy of the Freud Museum (20 Maresfield Gardens, NW3; 020 7435 2002; admission charge; www.freud.org.uk; Tube: Finchley Road). This was the home, study and consulting room of the father of psychoanalysis - and the grandfather of former Fenland MP Sir Clement Freud and painter Lucian Freud - for a final year after escape from Nazi Vienna.

For crackpot craziness book an appointment at Bedlam - now relocated to Beckenham and a small, free Bethlem Royal Hospital Archives and Museum (Monks Orchard Road, 020 8776 4307; www.bethlemheritage.org.uk; Train: Elmers End). See the old gateway statues of Raving and Melancholy Madness from the infamous institution and pictures by artists afflicted by mental health problems such as Richard Dadd (who killed his dad) and Louis Wain (who was said to have lapped milk from a saucer like his beloved cats).

But stand on the actual site of Bedlam you will need to enter a world of utter madness: the Imperial War Museum. T

t London Museums of Health and Medicine (www.medicalmuseums.org). Pre-booked guided tours, plus related walks and talks, can be arranged with Sue Weir on 020 7928 0765.