THE BEST AND THE BAWDIEST cartoons in the Library of Congress' show, "English Caricature: 1620 to the Present," come from the late 18th and early 19th centuries.

Caricaturists of yore got away with more. Virtually immune from prosecution, they could afford to be daring.

In that golden age of caricature, Thomas Rowlandson and James Gillray set the standard. A frequent target of Gillray's venom was Whig party leader Charles James Fox. In 1806, Gillray even followed him to his death bed: In "Visiting the Sick," published five weeks before his death, Fox is seen as raising himself up to ask, "Will no one give me a cordial?" Nearby, his mistress is being comforted.

In another print, an unknown contemporary of Gillray's pictures the Prince of Wales besporting himself in a bordello -- while James Fox, a recently acquired ally, throws up in a corner.

Fox dealt with the calumny of caricaturists by purchasing their work. King George IV paid the artists to suppress their caricatures, but kept copies for himself. By doing so he inadvertently formed the heart of the Royal Library Collection of political prints -- and the heart of this exhibition as well, as the Library of Congress bought that royal collection in 1920.

Social satire seems to have more staying power over the centuries than the very specific political cartoons. We don't have to know history to laugh at human foibles, to enjoy the comic absurdity of Rowlandson's "The Exhibition 'Stare-Case'. " In this 1800 crowd-scene at a Royal Academy exhibition, the fashionable attendees tumble like dominos down a winding staircase; ladies' skirts fly up above the waist.

Other caricatures are as durable as they are obvious: in "The Lady's Disaster," the lady's hoop skirt goes haywire, shocking a little chimney sweep. "Top and Tail" pokes fun at a woman's elaborate wig that covers all but her tiny bare buttocks, legs and high heels.

At the same time the exhibit outlines 350 years of British caricature, it traces a people's history, and prejudices. There is much ado about John Bull foiling "the scheming French." And we get a view of American Revolutionary times from the Redcoats' side. One finds the reason why Yankee Doodle stuck a feather in his cap and called it macaroni: Macaronis -- dandies with absurd manners and dress -- were natural subjects for caricature.

Most of the 200 caricatures in this show are to be perused. But there are short-takes, too.

Twentieth-century cartoonist Gerald Scarfe draws an encounter between Cecil Beaton and Mick Jagger, who is mostly moue with memorable fish-flower lips. And Marc (Mark Boxer) takes us up to date on royalty with a drawing of a dashing-but-worried, bucktoothed Prince Charles.

Perhaps the most memorable picture in the show is one of Sir Robert Walpole, who was literally the butt of many jokes. In an anonymous 1740 drawing, the prime minister, or rather his bare posterior, blocks the gate to the treasury, exchequer and admiralty. A kiss will clear the way. THE REALM OF FOLLY: ENGLISH CARICATURE FROM 1620 TO THE PRESENT -- At the Library of Congress through February 17, 1984.