The Master is Here; He is Calling You!

Whatever our senses perceive in the consecrated host, even with the help of scientific instruments, is always of the same sort—a quality: the whiteness of the bread, its softness, its roundness, its smell, etc. These are attributes. We call them in the language of metaphysics, accidents. These are all our senses perceive. But from them, our mind discerns a deeper reality, something that underlies these qualities or accidents as their subject: the thing itself, which we call the substance. We know that through Christ’s words, that in the eucharistic species, none of the substance of the bread and wine remains, Their accidents or sensible qualities—as bread and wine—remain, though not, of course as accidents of Christ’s body and blood. They are held up solely by the will of God, who keeps them in existence, without inhering to any subject. True, before the Consecration what we have on the altar are bread and wine; but as soon as the words of the Consecration are pronounced, the whole substance of the bread and that of the wine disappear, and they become the body and blood of Jesus Christ. This change is called transubstantiation. Just as the words which God spoke in the Upper Room are the same as those that the priest now pronounces, so, too, the host is the same. Christ is really present.

Charles Belmonte:  Understanding the Mass, pp.12-13