The Matter and Form of the Sacrament of the Holy Eucharist

Constituent Parts of the Eucharist
The first element of the Eucharist is bread.
The matter of this Sacrament is twofold. The first element is wheaten bread, of which we shall discuss now. While the second we shall discuss later in this article. As the Evangelists, Matthew, Mark and Luke testify, Christ the Lord took bread into His hands, blessed, and broke, saying: This is My body (Matt. 26:26; Mark 14:22; Luke 22:19); and, according to John, the same Savior called Himself bread in these words: I am the living bread, that came down from heaven (John 6:41).
The sacramental bread must be wheaten.
There are, moreover, various sorts of bread, either because they are made up of different materials — such as wheat, barley, pulse, and other products of the earth; or because they have various qualities — some being leavened, others altogether without leaven. It is to be noted that, with regard to the former kinds, the words of the Savior show that the bread should be wheaten; for, according to the common usage, when we simply say bread, we are well understood to mean wheaten bread. This is also stated by a figure in the Old Testament because the Lord commanded that the loaves of proposition, which signified this Sacrament, should be made of fine flour.
The sacramental bread should be unleavened.
But as wheaten bread alone is to be considered the proper matter for this Sacrament — a doctrine which has been handed down by Apostolic tradition and confirmed by the authority of the Catholic Church — so it may be easily inferred from the doings of Christ the Lord that this bread should be unleavened. It was purified and instituted by Him on the first day of unleavened bread, on which it was not lawful for the Jews to have anything leavened in their houses (Matt. 26:17; Mark 14:12; Luke 22:7).
Unleavened bread not necessary.
This quality of the bread, however, is not to be considered so important that, if it be wanting, the Sacrament cannot exist; for both kinds are called by the one name and have the true and proper nature of bread. No one, moreover, is at liberty on his own private authority, or rather presumption, to transgress the laudable rite of his Church. And such departure is the less warrantable in priests of the Latin Church, clearly obliged as they are by the Supreme Pontiffs, to santicify the sacred mysteries with unleavened bread only.
The quantity of the bread.
With regard to the first matter of this Sacrament, let this exposition suffice. It is, however, to be observed, that the quantity of the matter to be sanctified is not defined since we cannot define the exact number of those who can or ought to receive the sacred mysteries.4
The second element of the eucharistic wine.
It remains for us to treat of the other matter and element of this Sacrament, which is wine pressed from the fruit of the vine, with which is mingled a little water.
That in the institution of this Sacrament our Lord and Savior made use of wine has been at all times the doctrine of the Catholic Church, for He Himself said: I will not drink from henceforth of this fruit of the vine until that day (Matt. 26:29; Mark 14:25). On this passage, Chrysostom observes: He says, “Of the fruit of the vine,” which certainly produced wine not water; as if he had it in view, even at so early a period, to uproot the heresy which declared that in these mysteries water alone is to be used.
Water should be mixed with the wine.
With the wine, however, the Church of God has always mingled water. First, because Christ the Lord did so, as is proved by the authority of the Councils and the testimony of St. Cyprian;6 next, because by this mixture is renewed the recollection of the blood and water that issued from His side. Water, also, as we read in the Apocalypse (17:15), signify the people; and hence, water mixed with the wine signifies the union of the faithful with Christ their Head. This rite, derived as it is from Apostolic tradition, the Catholic Church has always observed.
No other elements pertain to this Sacrament.
These, then, are the only two elements of this Sacrament, and with reason has it been enacted by many decrees that, although there have been those who were not afraid to do so, it is unlawful to offer anything but bread and wine.
Peculiar fitness of bread and wine.
We have now to consider the aptitude of these two symbols of bread and wine to represent those things of which we believe and confess they are the sensible signs.
In the first place, then, they signify to us Christ, as the true life of men; for our Lord Himself says: My flesh is meat indeed, and My blood is drink indeed (John 6:55). As, then, the Body of Christ the Lord furnishes nourishment unto eternal life to those who receive this Sacrament with purity and holiness, rightly is the matter composed mainly of those elements by which our present life is sustained, in order that the faithful may easily comprehend that the mind and soul are satisfied by the Communion of the precious Body and Blood of Christ.
These very elements serve also somewhat to suggest to men the truth of the Real Presence of the Body and Blood of the Lord in the Sacrament. Observing, as we do, that bread and wine are every day changed by the power of nature into human flesh and blood, we are led the more easily by this analogy to believe that the substance of the bread and wine is transformed, by the heavenly benediction, into the real Flesh and real Blood of Christ.
FORM OF THE EUCHARIST
The form to be used in the consecration of the bread is next to be treated of, not, moreover, in order that the faithful should be taught these mysteries unless necessity requires it; for this knowledge is not needful for those who have not received Holy Orders. The purpose (of this section) is to guard against most shameful mistakes on the part of priests, at the time of the consecration, due to ignorance of the form.
Form to be used in the Consecration of the bread.
We are then taught by the holy Evangelists, Matthew and Luke, and also by the Apostle, that the form consists of these words: This is my body; for it is written: Whilst they were at supper, Jesus took bread, and blessed it, and broke, and gave to his disciples, and said: Take and eat, This is My Body (Matt. 26:26; Mark 14:23; Luke 22:10; 1 Cor. 11:24).
This form of consecration having been observed by Christ the Lord has been always used by the Catholic Church. The testimonies of the Fathers, the enumeration of which would be endless, and also the decree of the Council of Florence, which is well known and accessible to all, must here be omitted, specifically as the knowledge which they convey may be obtained from these words of the Savior: Do this for a commemoration of Me (Luke 22:19). For what the Lord enjoined was not only what He had done, but also what He had said; and especially is this true, since the words were uttered not only to signify but also to fulfill.
Form to be used in the Consecration of the wine.
With regard to the consecration of the wine, which is the other element of this Sacrament, the priest, for the purpose we have already assigned, ought of necessity to be well known with, and well comprehend its form. We are then strongly to believe that it consists in the following words: This is the chalice of My Blood, of the new and eternal testament, the mystery of faith, which shall be shed for you and for many, to the remission of sins. Of these words, the greater part is taken from Scripture; but some have been preserved in the Church from apostolic tradition.
Thus the words, this is the chalice, are found in St. Luke and in the Apostle (Luke 12:20; 1 Cor. 11:25); but the words that instantly follow, of My Blood, or my blood of the new testament, which shall be shed for you and for many to the remission of sins, are found partly in St. Luke and partly in St. Matthew (Luke 22:20; Matt. 26:28). But the words, eternal, and the mystery of faith have been taught us by holy tradition, the interpreter and keeper of Catholic truth.