蛇毒
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Snake Poison
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第1段
How it came about that snakes manufactured poison is a mystery. Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today. It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do. Poison to a snake is merely a luxury; it enables it to get its food with very little effort, no more effort than one bite. And why only snakes? Cats, for instance, would be greatly helped; no running fights with large, fierce rats or tussles with grown rabbits—just a bite and no more effort needed. In fact, it would be an assistance to all carnivores though it would be a two-edged weapon when they fought each other. But, of the vertebrates, unpredictable Nature selected only snakes and one lizard. One wonders also why Nature, with some snakes, concocted poison of such extreme potency.
蛇如何产生毒液，是一个谜。蛇原本像人类唾液一样温和的消化液，经过漫长的时间，演化成了至今仍无法分析清楚的毒液。毒液不是生存竞争强加给它们的，它们也可以不靠毒液而抓到猎物谋生，就像今天成千上万的无毒蛇那样。毒液对毒蛇来说是多么地奢侈，它使毒蛇得以轻松一口便得到食物。为什么只有蛇才有毒液呢？譬如说，如果猫有毒液，那将大有裨益，猫不必再和又大又凶猛的老鼠跑着打斗了，也不必再和大兔子打做一团了，只要咬一口，就不必费力了。 因此，任何食肉动物有了毒液，都能从中获益。 不过，当动物们相互撕打时，毒液就成了双刃剑。然而，在脊椎动物中，大自然神秘莫测地只选择了蛇（还有一种蜥蜴）。人们也对大自然为什么借某些蛇类调制出如此高效的毒液而惊叹不解。
第2段
In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not; some snakes manufactured a poison different in every respect from that of others, as different as arsenic is from strychnine, and having different effects. One poison acts on the nerves, the other on the blood.
唾液转变成毒液，人们可能以为是固定程序起作用。其实没有。有些蛇产生的毒液与另外一些毒蛇所产生的毒液完全不同，效果各异，就像砒霜跟马钱子碱不同一样。一种毒液作用于神经，另一种则作用于血液。
第3段
The makers of the nerve poison include the mambas and the cobras and their venom is called neurotoxic. Vipers adders and rattlesnakes manufacture the blood poison, which is known as haemolytic. Both poisons are unpleasant, but by far the more unpleasant is the blood poison. 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. Be that as it may, the nerve poison does its business with man far more quickly than the blood poison. This, however, means nothing. Snakes did not acquire their poison for use against man but for use against prey such as rats and mice, and the effects on these of viperine poison is almost immediate.
产生神经毒液的蛇包括树眼镜蛇和眼镜蛇，它们的毒液称为神经毒液。蝰蛇（蝮蛇）和响尾蛇产生血液毒素，称为溶血性毒液。这两种毒液都很可怕，但溶血性毒液更为可怕。据说，神经毒液相比之下较为原始，而溶血性毒液，打个比方说，是根据改良配方生产的一种较新的产品。不过，神经毒液比溶血性毒液在人身上起作用快得多。 可这并没有什么关系。因为蛇有毒液不是用来对付人的，而是对付它的猎物，诸如鼠类，毒液对这些猎物几乎立即见效。
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译文与解析据吴应时整理资料及本站首轮审校稿；词伙与练习提示为本站学习设计。原PDF第80—83页，2022年2月第2版。