Their charges are susceptible to intestinal nematode worms which cause them to waste away and can, in severe cases, kill them.

他们的羊群容易受到肠道线虫的影响，这些蠕虫会使它们日渐消瘦，在严重的情况下，会令它们死亡。

What intestinal worms do, really, is limit potential.

肠道蠕虫的作用实际上是限制潜力。

And it may be asked what advantage, as far as we can see, would it be to an infusorian animalcule—to an intestinal worm—or even to an earth-worm, to be highly organised.

可能有人会问， 就我们所知， 高度组织化对纤毛虫——对肠道蠕虫——甚至对蚯蚓有什么好处。