Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 104. Transubstantiation A Total Conversion — This conversion, then, is so effected that the whole substance of the bread is changed by the power of God into the whole substance of the body of Christ, and the whole substance of the wine into the whole substance of His blood, and this, without any change in our Lord Himself. He is neither begotten, nor changed, not increased, but remains entire in His substance.