But no one knows what Widow Wadman first saw in Toby, because he certainly wasn't a water drinker, weaver, gardener, or gladiator—so it must have been his leg, even though his leg looked perfectly sound (plump and muscular, to be exact).
This is really torturing Tristram, because he can't figure out the cause and it's making the story hard to write. He's got enough stuff to deal with.