A figurative story is told like this: If you put a frog into a pot of boiling water, it will keep jumping for escape; if it is placed in cool and pleasant water and it is heated slowly enough, the frog will be boiled alive.
The fact is...
Though the old experiments1 have shown this story is indeed true, many people in recent time have debunked it.
Vic's2 answer was as follows: "The legend is entirely incorrect! The `critical thermal maxima' of many species of frogs have been determined by several investigators. In this procedure, the water in which a frog is submerged is heated gradually at about 2 degrees Fahrenheit per minute. As the temperature of the water is gradually increased, the frog will eventually become more and more active in attempts to escape the heated water. If the container size and opening allow the frog to jump out, it will do so."
"The Legend of the Boiling Frog Is Just a Legend" by Whit Gibbons, Ecoviews, November 18, 2002.
Professor Doug Melton, Harvard University Biology Department, says, "If you put a frog in boiling water, it won't jump out. It will die. If you put it in cold water, it will jump before it gets hot -- they don't sit still for you."
"Next Time, What Say We Boil a Consultant" by Fast Company, October, 1995.
"Rubbish!" say the people who know about frogs. "If a frog had a means of getting out, it certainly would," according to the curator3 of amphibians at the US national Museum of Natural History.
"Ecological Debt and Climate Change" by Andrew Simms, May 13, 2005.
It only needs a small experiment for verification, which could be operated at a home kitchen. I rather not harm a little animal for only my curiosity, but believe this urban myth is busted! Thought it is still a very good analogy to many phenomena and behavior, I'll try to not use this for metaphor because it is inevitable to mislead people into believing this is a true story. I hope there is another good story for the same metaphor, and if you know one, please speak out the story.