Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 54. Concerning this form no one can doubt, if he here also attend to what has been already said about the form used in the consecration of the bread. The form to be used (in the consecration) of this element, evidently consists of those words which signify that the substance of the wine is changed into the blood of our Lord. since, therefore, the words already cited clearly declare this, it is plain that no other words constitute the form.