本篇文章共分 8 段，從自發生成論的主要論點開始，說明歷來對此主張採支持與反對的兩派科學家如何利用不同設計的實驗來強化各自的主張，並解釋法國醫生巴斯德如何利用巧妙的實驗設計終結此一困擾科學界的難題。

本篇考題英文原文與對應之中文翻譯整理如下。練習作答解題時若有對語意不清楚之處，請仔細查閱對照，以提升閱讀理解能力。

The Debate over Spontaneous Generation 關於自發生成的爭論

1. 自發生成論

   Until the second half of the nineteenth century, many scientists and philosophers believed that some forms of life could arise spontaneously from nonliving matter; they called this hypothetical process spontaneous generation. Not much more than 100 years ago, people commonly believed that toads, snakes, and mice could be born of moist soil; that flies could emerge from manure; and that maggots, the larvae of flies, could arise from decaying corpses.

   直到 19 世紀下半葉，許多科學家和哲學家都相信，一些生命形式可以從非生命物質中自發產生；他們把這種假設的過程稱為自發生成。不到 100 年前，人們普遍認為蟾蜍、蛇和老鼠可以從潮濕的土壤中誕生；蒼蠅可以從糞便中出現；蒼蠅的幼蟲蛆蟲可以從腐爛的屍體中出現。

2. 雷迪實驗

   A strong opponent of spontaneous generation, the Italian physician Francesco Redi, set out in 1668 to demonstrate that maggots did not arise spontaneously from decaying meat. Redi filled three jars with decaying meat and sealed them tightly. Then he arranged three other jars similarly but left them open. Maggots appeared in the open vessels after flies entered the jars and laid their eggs, but the sealed containers showed no signs of maggots. Still, Redi’s antagonists were not convinced; they claimed that fresh air was needed for spontaneous generation. So Redi set up a second experiment, in which three jars were covered with a fine net instead of being sealed. No larvae appeared in the net-covered jars, even though air was present. Maggots appeared only when flies were allowed to leave their eggs on the meat. Redi's results were a serious blow to the long-held belief that large forms of life could arise from nonlife. However, many scientists still believed that tiny microorganisms were simple enough to be generated from nonliving materials.

   意大利醫生弗朗西斯科．雷迪是自發生成的強烈反對者，他在 1668 年著手證明蛆蟲不會從腐爛的肉中自發產生。雷迪在三個罐子裡裝滿了腐爛的肉，並把它們密封起來。然後，他以類似的方式安排另外三個罐子，但讓它們敞開。在蒼蠅進入罐子並產卵後，蛆蟲出現在開放的容器中，但密封的容器沒有顯示出蛆蟲的跡象。儘管如此，雷迪的反對者仍不相信；他們聲稱，自發生成需要新鮮空氣。因此，Redi 建立了第二個實驗，在其中用一張細網覆蓋三個罐子，而不是密封。即使有空氣存在，被網覆蓋的罐子裡也沒有幼蟲出現。只有當蒼蠅被允許在肉上留下它們的卵時才會出現蛆蟲。雷迪的結果是對長期以來持有的大型生命形式可能來自非生命的信念的嚴重打擊。然而，許多科學家仍然相信，微小的微生物簡單到可以從非生物材料中產生。

3. 尼德姆實驗與斯帕蘭札尼主張

   The case for spontaneous generation of microorganisms seemed to be strengthened in 1745, when John Needham, an Englishman, found that even after he heated nutrient fluids (chicken broth and corn broth) before pouring them into covered flasks, the cooled solutions were soon teeming with microorganisms. Needham claimed that microbes developed spontaneously from the fluids. Twenty years later, Lazzaro Spallanzani, an Italian scientist, suggested that microorganisms from the air probably had entered Needham's solutions after they were boiled. Spallanzani showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth. Needham responded by claiming the “vital force” necessary for spontaneous generation had been destroyed by the heat and was kept out of the flasks by the seals.

   1745 年，英國人約翰．尼德姆發現，即使在加熱營養液（雞湯和玉米湯）後再將其倒入有蓋燒瓶中，冷卻後的溶液也很快充滿了微生物，這似乎加強了微生物自發生成的理由。尼德姆聲稱，微生物是從這些液體中自發發展起來的。20 年後，意大利科學家拉扎羅．斯帕蘭札尼提出，空氣中的微生物可能在煮沸後進入尼德姆的溶液。斯帕蘭扎尼表示，在燒瓶中密封後加熱的營養液並沒有出現微生物生長。尼德姆回應說，自發生成所需的「生命力」已被高溫破壞，並被密封圈擋在了燒瓶之外。

4. 生命力的提出

   This intangible “vital force” was given all the more credence shortly after Spallanzani's experiment, when Laurent Lavoisier showed the importance of oxygen to life. Spallanzani's observations were criticized on the grounds that there was not enough oxygen in the sealed flasks to support microbial life.

   這種無形的「生命力」在斯帕蘭扎尼的實驗後不久就被賦予了更多的認可，當時勞倫特．拉瓦錫證明了氧氣對生命的重要性。斯帕蘭扎尼的觀察受到了批評，理由是密封瓶中沒有足夠的氧氣來支持微生物生命。

5. 問題懸而未決

   The issue was still unresolved in 1858, when the German scientist Rudolf Virchow challenged spontaneous generation with the concept of biogenesis, the claim that living cells can arise only from preexisting living cells. Arguments about spontaneous generation continued until 1861, when the work of the French scientist Louis Pasteur ended the debate.

   這個問題在 1858 年仍未解決，當時德國科學家魯道夫．維爾喬夫用生物發生的概念挑戰自發生成，即聲稱活細胞只能從預先存在的活細胞產生。關於自發生成的爭論一直持續到 1861 年，當時法國科學家路易斯．巴斯德的研究終結了這場爭論。

6. 巴斯德實驗

   With a series of ingenious and persuasive experiments, Pasteur demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but air itself does not create microbes. He filled several short-necked flasks with beef broth and then boiled their contents. Some were then left open and allowed to cool. In a few days, these flasks were found to be contaminated with microbes. The other flasks, sealed after boiling, were free of microorganisms. From these results, Pasteur reasoned that microbes in the air were the agents responsible for contaminating nonliving matter such as the broths in Needham’s flasks.

   經由一系列巧妙而有說服力的實驗，巴斯德證明了微生物存在於空氣中並能污染無菌溶液，但空氣本身並不產生微生物。他將幾個短頸瓶裝滿牛肉湯，然後將其內容物煮沸。然後將一些燒瓶打開，讓其冷卻。幾天後，這些燒瓶被發現被微生物污染了。其他燒瓶在煮沸後密封，沒有微生物。根據這些結果，巴斯德推斷空氣中的微生物是污染非生物物質的媒介，如尼德姆燒瓶中的肉湯。

7. 巴斯德進階實驗

   Pasteur next placed broth in open-ended long-necked flasks and bent the necks into S-shaped curves. The contents of these flasks were then boiled and cooled. The broth in the flasks did not decay and showed no signs of life, even after months. Pasteur’s unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might have contaminated the broth.

   巴斯德接下來將肉湯放在開口的長頸瓶中，並將瓶頸彎曲成 S 形曲線。然後將這些燒瓶中的內容物煮沸並冷卻。燒瓶中的肉湯沒有腐爛，甚至在幾個月後也沒有顯示出生命的跡象。巴斯德的獨特設計允許空氣進入燒瓶，但彎曲的瓶頸困住了任何可能污染肉湯的空氣中的微生物。

8. 自發生成論遭推翻

   Pasteur showed that microorganisms can be present in nonliving matter—on solids, in liquids, and in the air. His work provided evidence that microorganisms cannot originate from mysterious forces present in nonliving materials. Rather, any appearance of ‘‘spontaneous” life in nonliving solutions can be attributed to microorganisms that were already present in the air or in the fluids themselves.

   巴斯德表明，微生物可以存在於非生物物質—固體、液體和空氣中。他的研究提供了證據，證明微生物無法源自於非生物物質中的神秘力量。相反的，在非生物溶液中出現的任何「自發」生命，都可以歸因於已經存在於空氣或液體中的微生物。