Bodies Politic: disease, death and doctors in Britain 1650-1900, by Roy Porter

Doctors have become our secular saints, yet for centuries they were ridiculed as frauds, says Felipe Fernández-Armesto

Health is the new goodness, the only value on which everyone seems to agree. It is the pollsters', and therefore the politicians', top election issue. Health carers are people's favourite professionals. Doctors and nurses are good guys in broadcast soap and printed pap. They represent the friendly face of expertise ­ science hallowed by humanity. Politicians compete for their endorsement with spendthrift abandon.

Health professionals do weird things which ought to inspire distrust: they root around inside bodies, peer at excreta, carve limbs, consort with multinational drug companies, promote scares and handle dangerous substances. Yet today, despite unprecedented scandals about medical negligence and malevolence, they are idolised. Less surprisingly, for most of history health-mongers have been feared or resented ­ accepted, at best, as a costly, risky necessity. When and why did they make the upgrade from villains to heroes?

The problem becomes visible in the well-illustrated pages of Roy Porter's new book. Porter is one of the world's best historical writers: his prose is pithy, witty, vivid, engaging and perfectly paced. He has a keen eye for evidence and can wrest conclusions with analytical rigour and imaginative subtlety. He masters fact and theory with equal ease and wields both lightly but powerfully. All his books please, stimulate and teach. He achieves all this with amazing consistency, in a series of major works which appear frequently without sacrifice of quality.

The new volume covers a neglected aspect of the modern history of medicine in Britain: the visual representation of doctors and disease. The well-chosen material ­ some edifying but most of it flesh-creepingly, sickeningly revolting ­ comes mainly from Porter's own beloved 18th century, with some reference to the 19th.

British artists seem to have discovered medicine relatively late. There are no 17th-century British canvases to rival Rembrandt's "The Anatomy Lesson". There was no English equivalent of Molière's Le Malade Imaginaire to inspire engravers. When the subject began to be exploited on a large scale in the 18th century, it was chiefly the preserve of caricaturists. The doctor, according to Pinel in France in 1793, "seems to parody medicine rather than practise it".

In England, the satirists agreed. Of course, official portraitists made sages of their sitters: "professional image-building" garbed lean physicians in learned robes with sober countenances to signify "wisdom, gravitas, venerability," and an "air of unworldliness". But there was little public demand for pictures like these. Licensed physicians encouraged satirists in the depiction of quackery, inept, ignorant, greedy and immoral: the "turdy-facy, nasty-paty, lousy-fartical" charlatan; "the greasy nurse, the gossiping midwife, and the threadbare druggist selling under-the-counter love philtres and poisons".

Despite the doctors' attempts to close their shop and professionalise their ranks from Tudor times onwards, the distinction between quacks and hacks ­ folk-healers, faith-healers, nostrum-peddlers and charlatans on the hand, scientific professionals on the other ­ was long unclear. Surgeons migrated between the categories. In consequence, doctors were depicted with the same ribaldry as their rivals, albeit, as Porter argues, in images that usually were "not unduly vicious".

The caricaturists' efforts informed the public: even the poor saw the prints in shop windows. Cartoons featured rapacious doctors, as prolific with bills as with pills; tricksters proffering placebos or plying gimcrack surgery; human buzzards preying on the sick; doddering doctors, dangerous to their patients; monstrous medics, misshapen by contact with disease, disfigured by "symptoms of inner states... the signature of wrong".

Lubricity masqueraded as gynaecology and ghoulishness as anatomy. Pagan doctors defied Providence ­ atheism does seem to have been more widely espoused among physicians than in other branches of learning. The metaphors of medicine were appropriated for politics. The "body politic", racked with agues, moribund with neglect, anaemic with fiscal blood-loss, or smitten with the wounds of defeat, was victimised by specialist physicians. Rulers and statesmen appeared as quacks or thaumaturges.

Porter argues that the doctors got from the artists more or less what they asked for. Early-modern medicine was more spectacle than science. Its impact was theatrical. It relied on display. Medicine was "a corpus of identities, teachings and practices to be respected ­ or reviled ­ for their theatrical, spectacular and even magical aspects". The struggle against sickness was "a sacred drama". The artists' work reflected, in grotesque form, doctors' self-perceptions. It captured something of their methods. While "medical know-how was shared between doctors and patients" ­ a situation which, Porter claims, prevailed until late 19th-century science "gave doctors the whip-hand" ­ medicine-men were relatively easy to ridicule.

Victorian "progress", however, made their practices more esoteric and more scientific: a technological carapace protected it from lampoons. New efforts at professionalisation erected unmistakable boundaries between insiders and the excluded. Hero-worship became a fashion from which doctors benefited: it was the age of George Eliot's Dr Lydgate and Anthony Trollope's Dr Thorne. Punch inherited the old satirical traditions, but re-targeted them. Satire "shifted from the physician... to the ignorance and obtuseness of the (typically lower-class) patient". The "post-Nightingale nurse" emerged: the ministering angel replaced the bedside harpy. The physician was healed.

Could we return to an era of unhealthy contempt for medicine? Increasing privatisation seems inevitable: we can imagine a time when the "carers" will be transformed, in public perceptions, into graspers, reminiscent of 18th-century stereotypes. Deficient funds for research and education are already teasing unease in wards and waiting-rooms. In a litigious society, it pays to challenge doctors' competence and hospitals' healthiness. As abortions and mercy-killings proliferate, doctors will be cast again by satirists as dealers in death.

When microbes win the medicine-wars, medical ignorance and impotence will be lampoonists' fodder once more. Roy Porter's book illuminates the past. Present trends make it also seem ominously prophetic.