3. THE INSTITUTION, NATURE, AND PRINCIPAL PARTS OF THE MASS
At the Last Supper the Son of God changed bread into His body, and wine into His blood; He then gave both to the apostles, bidding them eat and drink the same.
We are told that after the washing of the feet Our Lord sat down at the table, took bread in His hands, looked up to heaven, gave thanks, blessed it, broke it, and gave it to His apostles, saying: “Take ye and eat; this is My body.” And after the apostles had received the body of Christ, He took the chalice in which was wine, gave thanks, blessed it, and gave it to His disciples, saying: “Drink ye all of this, for this is My blood; the blood of the new, the eternal covenant, the mystery of faith (a mystery for the trial of our faith), which shall be shed for you and for many for the remission of sins. Do this for a commemoration of Me.” (These are known as the words of consecration.)
After the consecration, the species or appearance of the bread and wine still remained the same.
The body of Christ had not the appearance of flesh, but the appearance of bread; it had the smell, the taste, the color, the weight, etc., of bread; the species was in fact retained. Nor did the blood of Christ bear the appearance of blood, but of wine; it had the smell, the taste, the color, etc., the ordinary appearance of wine. (This subject will be enlarged upon in the instructions concerning the Adorable Sacrament of the Altar.)