Chewing is a comfort to all sorts of animals - humans included. It's a reflex in babies, and throughout history grown-ups have enjoyed exercising their jaws.
The Ancient Greeks liked to chew things over with a mouthful of mastiche (resin from the mastic tree), American Indians used spruce bark, and in Victorian times a wad of tobacco was the champer's choice.
But the Mayan Indians' masticating material proved most durable. They had been chewing chicle, the gum of the sapodilla tree, for centuries when, in 1870, an enterprising Mexican offloaded a ton of it to an American inventor, Thomas Adams Sr.
He found it was softer, smoother and longer lasting than the sweetened paraffin wax then being sold in shops. And, by adding corn syrup, he discovered that the previously impervious gum could be made to take on new flavours. A marketing phenomenon was born.
William Wrigley's spearmint gum was made world famous in the early 1900s on the strength of one of the first mass media advertising campaigns, and in the Seventies a packet of Wrigley's was the first product to be sold with a barcode. More than pound;200 million worth of the sticky stuff is sold in Britain each year.
As the ver-present oral accessory of GIs, rock 'n' rollers and moody teenagers, chewing gum gave the chewer instant attitude. It was cool and youthful as well as dumb and antisocial. Architect Frank Lloyd Wright famously dismissed television as "chewing gum for the eyes" and it is the scourge of street cleaners - there are an estimated 300,000 discarded gobbets on London's Oxford Street at any one time.
But some clever innovations have smartened up its reputation. Added ingredients can now freshen your breath, whiten your teeth, unblock your nose or help you give up smoking. In Finland they even make gum with echinacea (to strengthen the immune system) and gingko biloba (to enhance memory). Dentists testify that chewing sugar-free varieties increases your saliva production, so cutting down on tooth decay.
Chewing gum can be good for the soul - in the United States, you can buy Bible Gum which features a verse from the holy book on every packet. And research has shown that it can even help you slim. Steady chewing uses up 11 calories an hour, so by chewing a sugar-free brand every waking hour for a year, you would lose up to an incredible 11 pounds. By gum!