Alfred had learned many of their ballads in his youth,

阿尔弗德年轻时学过许多民歌，

acquired this man-made disease as a pestilence.

而欧洲自己却染上了这种人为的瘟疫般的疾病。

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.

为什么只有蛇才有毒液呢？譬如说，如果猫有毒液，那对猫会大有帮助，它就不必再和又大又凶的老鼠边跑边博斗了，也不必再和大兔子扭斗了，只要咬一口，就不必再费大力气。

but a medicine that had worked so well in one form of illness would surely be of equal benefit in another,

只知道一种药对一种病有好处，肯定对另一种病也会有好处。

is to some degree inevitable.

在某种程度上是不可避免的。

or even the universe itself, must in the nature of things 'wear out'.

甚至宇宙本身，从事物的本质上来说都会磨损掉"。