Death and taxes are no longer as certain as Benjamin Franklin's famous saying would have it. Taxes aren't paid by the rich. Death in a secular and medicalised world has been made into something to be put off. All credit then to the Wellcome Foundation for holding a show that reminds us that death has been an intrinsic part of life through most of human history. Plague, famine and war made certain that it was all around the living, something to be feared, embraced and prepared for. Take heed of death, said the late medieval church, for judgement will surely follow. Embrace death said the Mexican celebrators of the Day of the Dead, for through it you honour your ancestors. Accept it as a good thing, taught the Buddhists, for it will be followed by rebirth in an endless cycle until you can break free of it altogether.
Wellcome Death may not be the best image to draw in the crowds. But in fact it is a surprisingly approachable exhibition, full of colour, inventiveness and occasional fun. That is primarily due to the private collection from which the show is drawn. Over the last dozen years, Richard Harris, a Chicago print dealer and book collector, has amassed some 2,000 artefacts, paintings, memorabilia and ephemera devoted to the subject, of which some 300 are on display here.
His collection was less the product of personal concern with the subject, he explains, than a desire to build a holding for public display in his retirement years, inspired by a small show of memento mori objects seen at the Maastricht Fair. "I went back to Chicago," he recalls, "and sought the advice of an independent art expert who said 'yes, we could find some 40 works to make a gathering of masterpieces'. But I came away thinking, no, that's not what I want. What I really wish is to gather everything about it, great and small, without regard to prestige."
The result is a collection filled with Harris's sense of opening avenues and new finds but carefully selected and spaciously displayed by the curator, Kate Forde. As a book dealer, Harris started with a volume of the Nuremberg Chronicle published in 1493 containing engravings of the Dance of Death theme that so obsessed the art of the late Middle Ages. Sometimes playing a violin, sometimes just dancing, death as a skeleton steals up on rich and poor, regardless of rank or virtue. On show also are the complete sets of Jacques Callot's Miseries of War, Goya's The Disasters of War and Otto Dix's War – surely the greatest statements on the horrors of conflict ever made in art. How anyone could go to war after seeing Goya's agonised depictions of the inhumanity it brings on all sides or Otto Dix's visions of death and destruction in the First World War in which he served is something that only the politicians who lead us there could answer.
The violence of death is never far from its treatment in European culture nor the yearning for a "good death" in bed, surrounded by family and priest to see the soul on to its next world. The grinning skull behind the painted face of fashion and youth is a constant theme of painting. Go to the more popular ephemera of playing cards, puppets and prints and it is treated more humorously. There is a group of US puppets to remind one that skeletons are part of the play of children, no more so than in the burgeoning celebration of Hallowe'en.
Other cultures have taken death to heart as part of popular belief in spirits and the worship of ancestors. There's a splendid papier mâché mask by a notable "cartoneros" sculptor, and a series of pictures, to remind one of Mexico's Day of the Dead festival. The demons of the Himalayas are just as ferocious in aspect and ritual, representations of the sorrows and evils of the world that have to be conquered. But then a cheerful Japanese painting, Frolicking Skeletons by Kawanabe Kyosai (1831-1889) can't fail to raise a smile with its jangling, dancing and chasing skeletons as a seated guardian figure from South Sulawesi in Indonesia – a recent purchase – looks positively serene in its unblinking gaze.
Not the least of the virtues of the Richard Harris Collection is that it includes contemporary art and works commissioned by Harris himself. A one-ton chandelier made up of plaster casts of bones, In the Eyes of Others, by the British artist, Jodie Carey, presents both the air of luxury with the reality of bone. A startling life-size plaster and wax image of a truncated torso figure on a crate addressed to the artist by the British sculptor John Isaacs, Are You Still Mad at Me? shocks you into questioning pain inflicted, while an installation by June Leaf, Gentleman on Green Table, is of a skeletal figure in tin and wire leaning forward in pain and uncertainty. In a series commissioned from the Mexican Marcos Raya, the artist pastes on skulls and empty eye sockets on to family photographs, while another commission, by the Hungarian artist Balint Zsako makes a collage of all the bones in a body as engraved by a 17th-century artist.
However wide-ranging, no exhibition can be fully comprehensive on a subject as big as this. One could have done with some Egyptian objects to reflect an obsession with death and afterlife that survives to this day in the City of the Dead. Although the exhibition touches on it, there was something supremely sentimental, perverse even, in the 19th-century fascination with beauty in death and its place as the highest expression of love. The agony is there in the prints of Käthe Kollwitz's Tod und Frau from 1910 and the prints of James Ensor but not the unsettling eroticism of the corpse in Klimt and the Pre-Raphaelites.
But that is the beauty of the Harris Collection. It makes you think positively about our end. For us, as for Harris, the gathering of objects becomes a means of exploration not revulsion. Has he finished with it? Stupid question. He's just bought an old Chevy Impala painted all over for the Day of the Dead. And it runs.
Death: A Self-Portrait, the Richard Harris Collection, Wellcome Collection, London NW1 (020 7611 2222) to 24 February