Greene uses metaphors, symbols and similes to convey his idea of the bleakness of human life.

In the very first chapter, Mr. Tench waits for an ether cylinder that never arrives. Since he is a dentist, the purpose of the cylinder is to anaesthetize his patients from the pain of surgery. The fact that the cylinder does not arrive (and we later see Mr. Tench performing dental work on the Chief of Police without anaesthetic), suggests that the pain of life cannot be avoided. The absent ether cylinder is thus a symbol for a nonexistent balm for human misery, whether mental or physical.

The scene in which the priest spends a night in jail (Part II, Chapter 3) is also symbolic. The jail is a metaphor for the entire world. It is a place of darkness and misery. Life goes on (as the copulating couple shows) but humans must stumble on through it without any light or guidance. It is a grim vision of human life reduced to its essential nature. The priest makes the point explicit when he realizes that “this place was very like the world elsewhere: people snatched at causes of pleasure and pride in cramped and disagreeable surroundings: there was no time to do anything worth doing, and always one dreamed of escape.”

The novel contains many striking similes that also point to the inherent corruption in human life. The priest believes that “evil ran like malaria in his veins” (Part III, Chapter 1); of his daughter he believes that “The knowledge of the world lay in her like the dark explicable spot in an X-ray photograph” (Part II, Chapter 3); and again he observes of his daughter, “The world was in her heart already, like the small spot of decay in a fruit” (Part II, Chapter 1).

Other similes are equally striking, each in their own way, as when the priest reflects on his faith: “He was on the defensive all the time about his faith, as if he was perpetually conscious of some friction, like that of an ill-fitting shoe” (Part III, Chapter 1). When the priest hears the mestizo’s story that the dying American asked for him, he disbelieves most of it, but the note from the American convinces him: “But what remained was this note, like a memorial stone you couldn’t overlook” (Part III, Chapter 1). The image contained in that simile is especially appropriate, since a memorial stone records someone’s life and death, like a tombstone. By going back to attend to the American, the priest is effectively ensuring his own death.