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The boiling frog is an anecdote describing a frog slowly being boiled alive. The premise is that if a frog is placed in boiling water, it will jump out, but if it is placed in cold water that is slowly heated, it will not perceive the danger and will be cooked to death. The story is often used as a metaphor for the inability or unwillingness of people to react to or be aware of threats that occur gradually. According to contemporary biologists, the premise of the story is false: a frog submerged and gradually heated will jump out.〔("The legend of the boiling frog is just a legend" ) by Whit Gibbons, ''Ecoviews'', November 18, 2002, retrieved November 24, 2015〕 However, some 19th-century experiments suggested that the underlying premise is true, provided the heating is sufficiently gradual. The story's common metaphorical use is a caution for people to be aware of even gradual change lest they suffer eventual undesirable consequences. ==The science== As part of advancing science, several experiments observing the reaction of frogs to slowly heated water took place in the 19th century. In 1869, while doing experiments searching for the location of the soul, German physiologist Friedrich Goltz demonstrated that a frog that has had its brain removed will remain in slowly heated water, but an intact frog attempted to escape the water when it reached 25 °C.〔 Other experiments showed that frogs did not attempt to escape gradually heated water. An 1872 experiment by Heinzmann demonstrated that a normal frog would not attempt to escape if the water was heated slowly enough, which was corroborated in 1875 by Fratscher. Goltz raised the temperature of the water from 17.5 °C to 56 °C in about ten minutes, or 3.8 °C per minute, in his experiment which prompted normal frogs to attempt to escape, whereas Heinzmann heated the frogs over the course of 90 minutes from about 21 °C to 37.5 °C, a rate of less than 0.2 °C per minute.〔 In "On the Variation of Reflex Excitability in the Frog induced by changes of Temperature" (1882) William Thompson Sedgwick writes: "in one experiment by Scripture the temperature was raised at a rate of 0.002°C per second, and the frog was found dead at the end of 2½ hours without having moved."〔Edward Scripture, ''(The New Psychology )'' (1897): (). The original 1872 experiment was cited in: Sedgwick, "On the Variation of Reflex Excitability in the Frog induced by changes of Temperature," ''Stud. Biol. Lab. Johns Hopkins University'' (1882): 385. "in one experiment the temperature was raised at a rate of 0.002 °C. per second, and the frog was found dead at the end of 2½ hours without having moved."〕 In 1888 Sedgwick explained the apparent contradiction between the results of these experiments as a consequence of different heating rates used in the experiments: "The truth appears to be that if the heating be sufficiently gradual, no reflex movements will be produced even in the normal frog; if it be more rapid, yet take place at such a rate as to be fairly called 'gradual', it will not secure the response of the normal frog under any circumstances".〔 Modern sources tend to dispute that the phenomenon is real. In 1995, Professor Douglas Melton, of the Harvard University Biology department, said, "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." Dr. George R. Zug, curator of reptiles and amphibians at the National Museum of Natural History, also rejected the suggestion, saying that "If a frog had a means of getting out, it certainly would get out."〔 In 2002 Dr. Victor H. Hutchison, Professor Emeritus of Zoology at the University of Oklahoma, with a research interest in thermal relations of amphibians, said that "The legend is entirely incorrect!". He described how the critical thermal maximum for many frog species has been determined by contemporary research experiments: as the water is heated by about 2 °F, or 1.1 °C, per minute, the frog becomes increasingly active as it tries to escape, and eventually jumps out if the container allows it.〔 None of these modern rebuttals – Melton, Zug, or Hutchison's – attempts to replicate an extremely slow-heating experiment as cited by Goltz or Scripture: only Hutchison did a thermal trial at over ''five times'' Goltz's slow rate and over ''nine'' times Scripture's 0.002 °C per second temperature rise. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Boiling frog」の詳細全文を読む スポンサード リンク
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