Lesson 20 Snake poison
第20課 蛇毒
First listen and then answer the following question.
聽(tīng)錄音，然后回答以下問(wèn)題。
What are the two different ways in which snake poison acts?
蛇毒是以哪兩種不同的方式起作用的？
How in came about that snakes manufactured poison is a mystery.
蛇是怎樣產(chǎn)生毒液的，這是一個(gè)謎。
Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today.
蛇的唾液本來(lái)和我們?nèi)说南阂粯尤岷?，但?jīng)過(guò)漫長(zhǎng)的時(shí)間，演變成了今天仍無(wú)法分析清楚的毒液。
It was not forced upon them by the survival competition;
毒液不是生存競(jìng)爭(zhēng)強(qiáng)加給它們的，
they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do.
它們也可以不用毒液捕捉動(dòng)物而生存，就像今天成千上萬(wàn)的無(wú)毒蛇那樣。
Poison to a snake is merely a luxury;
毒液對(duì)毒蛇來(lái)說(shuō)只不過(guò)是一種舒適生存的優(yōu)越手段，
it enables it to get its food with very little effort, no more effort than one bite.
它使蛇不用費(fèi)多大力氣就能捕獲到食物，輕咬一口即可。
And why only snakes?
為什么只有蛇才有毒液呢？
Cats, for instance, would be greatly helped;
譬如說(shuō)，如果貓有毒液，那對(duì)貓會(huì)大有幫助，
no running fights with large, fierce rats or tussles with grown rabbits--just a bite and no more effort needed.
它就不必再和又大又兇的老鼠邊跑邊博斗了，也不必再和大兔子扭斗了，只要咬一口，就不必再費(fèi)大力氣。
In fact, it would be an assistance to all carnivores though it would be a two-edged weapon when they fought each other.
因此，任何食肉動(dòng)物有了毒液，都能從中獲益。不過(guò)，當(dāng)它們相互撕打時(shí)，毒液就成了利弊參半的武，可以殺死對(duì)方，也可以被對(duì)方的毒液殺死。
But, of the vertebrates unpredictable Nature selected only snakes (and one lizard).
然而，在脊椎動(dòng)物中，大自然神秘模測(cè)地只選擇了蛇（還有一種蜥蜴），
One wonders also why Nature, with some snakes concocted poison of such extreme potency.
人們弄不清楚大自然為什么在某些蛇的身上調(diào)制出如此高效的毒液來(lái)。
In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not;
人們可能認(rèn)為，唾液轉(zhuǎn)變成毒液，其中有固定的程序。其實(shí)沒(méi)有。
some snakes manufactured a poison different in every respect from that of others,
有些蛇產(chǎn)生的毒液也在各方面與另外一些毒蛇產(chǎn)生的毒液不同，
as different as arsenic is from strychnine, and having different effects.
就像砒霜不同于馬錢(qián)子堿一樣。不同毒蛇產(chǎn)生的毒液產(chǎn)生的效果不同，
One poison acts on the nerves, the other on the blood.
一種毒液作用于神經(jīng)，另一種毒液作用于血液。
The makers of the nerve poison include the mambas and the cobras and their venom is called neurotoxic.
產(chǎn)生神經(jīng)毒液的蛇有一種非洲樹(shù)眼鏡蛇和眼鏡蛇，它們的毒液稱(chēng)為神經(jīng)毒素。
Vipers (adders) and rattlesnakes manufacture the blood poison, which is known as haemolytic.
蝰蛇（蝮蛇）和響尾蛇產(chǎn)生血液毒素，稱(chēng)為溶血性毒液。
Both poisons are unpleasant, but by far the more unpleasant is the blood poison.
這兩種毒液都很可怕，但溶血性毒液尤其厲害。
It is said that the nerve poison is the more primitive of the two, that the blood poison is, so to speak, a newer product from an improved formula.
據(jù)說(shuō)，神經(jīng)毒液在兩種毒液中是較為原始的一種，而溶血性毒液，打個(gè)比方說(shuō)，是根據(jù)改良配方生產(chǎn)的一種較新的產(chǎn)品。
Be that as it may, the nerve poison does its business with man far more quickly than the blood poison.
不過(guò)，神經(jīng)毒辣液比溶血性毒液在人身上起作用快得多。
This, however, means nothing.
但是，這沒(méi)有什么關(guān)系，
Snakes did not acquire their poison for use against man but for use against prey such as rats and mice,
因?yàn)樯哂卸疽翰皇怯脕?lái)對(duì)付人的，而是對(duì)付它的獵物，諸如鼠類(lèi)，
and the effects on these of viperine poison is almost immediate.
毒液對(duì)這些獵物會(huì)立刻起作用。
第20課 蛇毒
First listen and then answer the following question.
聽(tīng)錄音，然后回答以下問(wèn)題。
What are the two different ways in which snake poison acts?
蛇毒是以哪兩種不同的方式起作用的？
How in came about that snakes manufactured poison is a mystery.
蛇是怎樣產(chǎn)生毒液的，這是一個(gè)謎。
Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today.
蛇的唾液本來(lái)和我們?nèi)说南阂粯尤岷?，但?jīng)過(guò)漫長(zhǎng)的時(shí)間，演變成了今天仍無(wú)法分析清楚的毒液。
It was not forced upon them by the survival competition;
毒液不是生存競(jìng)爭(zhēng)強(qiáng)加給它們的，
they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do.
它們也可以不用毒液捕捉動(dòng)物而生存，就像今天成千上萬(wàn)的無(wú)毒蛇那樣。
Poison to a snake is merely a luxury;
毒液對(duì)毒蛇來(lái)說(shuō)只不過(guò)是一種舒適生存的優(yōu)越手段，
it enables it to get its food with very little effort, no more effort than one bite.
它使蛇不用費(fèi)多大力氣就能捕獲到食物，輕咬一口即可。
And why only snakes?
為什么只有蛇才有毒液呢？
Cats, for instance, would be greatly helped;
譬如說(shuō)，如果貓有毒液，那對(duì)貓會(huì)大有幫助，
no running fights with large, fierce rats or tussles with grown rabbits--just a bite and no more effort needed.
它就不必再和又大又兇的老鼠邊跑邊博斗了，也不必再和大兔子扭斗了，只要咬一口，就不必再費(fèi)大力氣。
In fact, it would be an assistance to all carnivores though it would be a two-edged weapon when they fought each other.
因此，任何食肉動(dòng)物有了毒液，都能從中獲益。不過(guò)，當(dāng)它們相互撕打時(shí)，毒液就成了利弊參半的武，可以殺死對(duì)方，也可以被對(duì)方的毒液殺死。
But, of the vertebrates unpredictable Nature selected only snakes (and one lizard).
然而，在脊椎動(dòng)物中，大自然神秘模測(cè)地只選擇了蛇（還有一種蜥蜴），
One wonders also why Nature, with some snakes concocted poison of such extreme potency.
人們弄不清楚大自然為什么在某些蛇的身上調(diào)制出如此高效的毒液來(lái)。
In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not;
人們可能認(rèn)為，唾液轉(zhuǎn)變成毒液，其中有固定的程序。其實(shí)沒(méi)有。
some snakes manufactured a poison different in every respect from that of others,
有些蛇產(chǎn)生的毒液也在各方面與另外一些毒蛇產(chǎn)生的毒液不同，
as different as arsenic is from strychnine, and having different effects.
就像砒霜不同于馬錢(qián)子堿一樣。不同毒蛇產(chǎn)生的毒液產(chǎn)生的效果不同，
One poison acts on the nerves, the other on the blood.
一種毒液作用于神經(jīng)，另一種毒液作用于血液。
The makers of the nerve poison include the mambas and the cobras and their venom is called neurotoxic.
產(chǎn)生神經(jīng)毒液的蛇有一種非洲樹(shù)眼鏡蛇和眼鏡蛇，它們的毒液稱(chēng)為神經(jīng)毒素。
Vipers (adders) and rattlesnakes manufacture the blood poison, which is known as haemolytic.
蝰蛇（蝮蛇）和響尾蛇產(chǎn)生血液毒素，稱(chēng)為溶血性毒液。
Both poisons are unpleasant, but by far the more unpleasant is the blood poison.
這兩種毒液都很可怕，但溶血性毒液尤其厲害。
It is said that the nerve poison is the more primitive of the two, that the blood poison is, so to speak, a newer product from an improved formula.
據(jù)說(shuō)，神經(jīng)毒液在兩種毒液中是較為原始的一種，而溶血性毒液，打個(gè)比方說(shuō)，是根據(jù)改良配方生產(chǎn)的一種較新的產(chǎn)品。
Be that as it may, the nerve poison does its business with man far more quickly than the blood poison.
不過(guò)，神經(jīng)毒辣液比溶血性毒液在人身上起作用快得多。
This, however, means nothing.
但是，這沒(méi)有什么關(guān)系，
Snakes did not acquire their poison for use against man but for use against prey such as rats and mice,
因?yàn)樯哂卸疽翰皇怯脕?lái)對(duì)付人的，而是對(duì)付它的獵物，諸如鼠類(lèi)，
and the effects on these of viperine poison is almost immediate.
毒液對(duì)這些獵物會(huì)立刻起作用。