Some London-folk continue to go about their business, thinking they are healthy and will be passed over. But secretly they have the plague in their blood: when the infection reaches their heart they fall dead upon the spot, so reports his man, as if struck by lightning. And this is a figure for life itself, the whole of life. Due preparation. We should make due preparation for death, or else be struck down where we stand. As he, Robinson, was made to see when of a sudden, on his island, he came one day upon the footprint of a man in the sand. It was a print, and therefore a sign: of a foot, of a man. But it was a sign of much else too. You are not alone, said the sign; and also, No matter how far you sail, no matter where you hide, you will be searched out.