"To understand transubstantiation, let's turn to a related word that is more familiar to us: transformation. Transformation means changing from one form to another, while transubstantiation means changing from one substance to another. Let's take an example. When we see a woman leaving the hairdresser's with a whole new hairstyle, we sometimes spontaneously exclaim: ‘What a transformation!’. No one would dream of exclaiming, ‘What a transubstantiation!’. And rightly so. Her form and external appearance have changed, but not her inner being and personality. If she was intelligent before, she is intelligent now; if she was not intelligent before, I am sorry to say that she is not intelligent now either. Appearances have changed, but not substance. In the Eucharist, exactly the opposite happens: substance changes, but appearances do not. The bread is transubstantiated, but not transformed; in fact, its appearance (form, taste, colour, weight) remains the same, while its profound reality has changed, it has become the body of Christ. The promise of Jesus heard at the beginning [of the 19th Sunday in Ordinary Time] has been fulfilled: "The bread that I will give is my flesh for the life of the world.""