Since Christ is present under the appearances of bread and wine in a sacramental way, the Blessed Eucharist is unquestionably a sacrament of the Church. Indeed, in the Eucharist the definition of a Christian sacrament as "an outward sign of an inward grace instituted by Christ" is verified.
The investigation into the precise nature of the Blessed Sacrament of the Altar, whose existence Protestants do not deny, is beset with a number of difficulties. Its essence certainly does not consist in the Consecration or the Communion, the former being merely the sacrificial action, the latter the reception of the sacrament, and not the sacrament itself. The question may eventually be reduced to this whether or not the sacramentality is to be sought for in the Eucharistic species or in the Body and Blood of Christ hidden beneath them. The majority of theologians rightly respond to the query by saying, that neither the species themselves nor the Body and Blood of Christ by themselves, but the union of both factors constitute the moral whole of the Sacrament of the Altar. The species undoubtedly belong to the essence of the sacrament, since it is by means of them, and not by means of the invisible Body of Christ, that the Eucharist possesses the outward sign of the sacrament. Equally certain is it, that the Body and the Blood of Christ belong to the concept of the essence, because it is not the mere unsubstantial appearances which are given for the food of our souls but Christ concealed beneath the appearances. The twofold number of the Eucharistic elements of bread and wine does not interfere with the unity of the sacrament ; for the idea of refection embraces both eating and drinking, nor do our meals in consequence double their number. In the doctrine of the Holy Sacrifice of the Mass, there is a question of even higher relation, in that the separated species of bread and wine also represent the mystical separation of Christ's Body and Blood or the unbloody Sacrifice of the Eucharistic Lamb.
The Sacrament of the Altar may be regarded under the same aspects as the other sacraments, provided only it be ever kept in view that the Eucharist is a permanent sacrament. Every sacrament may be considered either in itself or with reference to the persons whom it concerns. Passing over the Institution, which is discussed elsewhere in connection with the words of Institution, the only essentially important points remaining are the outward sign ( matter and form) and inward grace (effects of Communion), to which may be added the necessity of Communion for salvation. In regard to the persons concerned, we distinguish between the minister of the Eucharist and its recipient or subject.
(1) The Matter or Eucharistic Elements
(a) The first element is wheaten bread (panis triticeus), without which the "confection of the Sacrament does not take place" (Missale Romanum: De defectibus, sect. 3), Being true bread, the Host must be baked, since mere flour is not bread. Since, moreover, the bread required is that formed of wheaten flour, not every kind of flour is allowed for validity, such, e.g., as is ground from rye, oats, barley, Indian corn or maize, though these are all botanically classified as grain (frumentum), On the other hand, the different varieties of wheat (as spelt, amelcorn, etc.) are valid, inasmuch as they can be proved botanically to be genuine wheat. The necessity of wheaten bread is deduced immediately from the words of Institution: "The Lord took bread" (ton arton), in connection with which it may be remarked, that in Scripture bread (artos), without any qualifying addition, always signifies wheaten bread. No doubt, too, Christ adhered unconditionally to the Jewish custom of using only wheaten bread in the Passover Supper, and by the words, "Do this for a commemoration of me", commanded its use for all succeeding times. In addition to this, uninterrupted tradition, whether it be the testimony of the Fathers or the practice of the Church, shows wheaten bread to have played such an essential part, that even Protestants would be loath to regard rye bread or barley bread as a proper element for the celebration of the Lord's Supper.
The Church maintains an easier position in the controversy respecting the use of fermented or unfermented bread. By leavened bread (fermentum, zymos) is meant such wheaten bread as requires leaven or yeast in its preparation and baking, while unleavened bread (azyma, azymon) is formed from a mixture of wheaten flour and water, which has been kneaded to dough and then baked. After the Greek Patriarch Michael Cærularius of Constantinople had sought in 1053 to palliate the renewed rupture with Rome by means of the controversy, concerning unleavened bread, the two Churches, in the Decree of Union at Florence, in 1439, came to the unanimous dogmatic decision, that the distinction between leavened and unleavened bread did not interfere with the confection of the sacrament, though for just reasons based upon the Church's discipline and practice, the Latins were obliged to retain unleavened bread, while the Greeks still held on to the use of leavened (cf, Denzinger, Enchirid., Freiburg, 1908, no, 692), Since the Schismatics had before the Council of Florence entertained doubts as to the validity of the Latin custom, a brief defense of the use of unleavened bread will not be out of place here. Pope Leo IX had as early as 1054 issued a protest against Michael Carularius (cf. Migne, P. L., CXLIII, 775), in which he referred to the Scriptural fact, that according to the three Synoptics the Last Supper was celebrated "on the first day of the azymes" and so the custom of the Western Church received its solemn sanction from the example of Christ Himself.
The Jews, moreover, were accustomed even the day before the fourteenth of Nisan to get rid of all the leaven which chanced to be in their dwellings, that so they might from that time on partake exclusively of the so-called mazzoth as bread. As regards tradition, it is not for us to settle the dispute of learned authorities, as to whether or not in the first six or eight centuries the Latins also celebrated Mass with leavened bread (Sirmond, Döllinger, Kraus) or have observed the present custom ever since the time of the Apostles (Mabillon, Probst). Against the Greeks it suffices to call attention to the historical fact that in the Orient the Maronites and Armenians have used unleavened bread from time immemorial, and that according to Origen (In Matt., XII, n. 6) the people of the East "sometimes", therefore not as a rule, made use of leavened bread in their Liturgy. Besides, there is considerable force in the theological argument that the fermenting process with yeast and other leaven, does not affect the substance of the bread, but merely its quality. The reasons of congruity advanced by the Greeks in behalf of leavened bread, which would have us consider it as a beautiful symbol of the hypostatic union, as well as an attractive representation of the savor of this heavenly Food, will be most willingly accepted, provided only that due consideration be given to the grounds of propriety set forth by the Latins with St. Thomas Aquinas (III:74:4) namely, the example of Christ, the aptitude of unleavened bread to be regarded as a symbol of the purity of His Sacred Body, free from all corruption of sin, and finally the instruction of St. Paul (1 Corinthians 5:8) to keep the Pasch not with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth".
(b) The second Eucharistic element required is wine of the grape (vinum de vite). Hence are excluded as invalid, not only the juices extracted and prepared from other fruits (as cider and perry), but also the so-called artificial wines, even if their chemical constitution is identical with the genuine juice of the grape. The necessity of wine of the grape is not so much the result of the authoritative decision of the Church, as it is presupposed by her (Council of Trent, Sess. XIII, cap. iv), and is based upon the example and command of Christ, Who at the Last Supper certainly converted the natural wine of grapes into His Blood, This is deduced partly from the rite of the Passover, which required the head of the family to pass around the "cup of benediction" (calix benedictionis) containing the wine of grapes, partly, and especially, from the express declaration of Christ, that henceforth He would not drink of the "fruit of the vine" (genimen vitis). The Catholic Church is aware of no other tradition and in this respect she has ever been one with the Greeks. The ancient Hydroparastatæ, or Aquarians, who used water instead of wine, were heretics in her eyes.
The counter-argument of Ad. Harnack ["Texte und Untersuchungen", new series, VII, 2 (1891), 115 sqq.], that the most ancient of Churches was indifferent as to the use of wine, and more concerned with the action of eating and drinking than with the elements of bread and wine, loses all its force in view not only of the earliest literature on the subject (the Didache, Ignatius, Justin, Irenæus, Clement of Alexandria, Origen, Hippolytus, Tertullian, and Cyprian ), but also of non-Catholic and apocryphal writings, which bear testimony to the use of bread and wine as the only and necessary elements of the Blessed Sacrament. On the other hand, a very ancient law of the Church which, however, has nothing to do with the validity of the sacrament, prescribes that a little water be added to the wine before the Consecration (Decr. pro Armenis: aqua modicissima ), a practice, whose legitimacy the Council of Trent (Sess. XXII, can. ix) established under pain of anathema. The rigor of this law of the Church may be traced to the ancient custom of the Romans and Jews, who mixed water with the strong southern wines ( see Proverbs 9:2 ), to the expression of calix mixtus found in Justin (Apol., I, lxv), Irenæus (Adv. hær., V, ii, 3), and Cyprian (Ep. lxiii, ad Cacil., n. 13 sq.), and especially to the deep symbolical meaning contained in the mingling, inasmuch as thereby are represented the flowing of blood and water from the side of the Crucified Savior and the intimate union of the faithful with Christ (cf. Council of Trent, Sess. XXII, cap. vii).
(2) The Sacramental Form or the Words of Consecration
The objection that the mere historical recitation of the words of Institution taken from the narrative of the Last Supper possesses no intrinsic consecratory force, would be well founded, did the priest of the Latin Church merely intend by means of them to narrate some historical event rather than pronounce them with the practical purpose of effecting the conversion, or if he pronounced them in his own name and person instead of the Person of Christ, whose minister and instrumental cause he is. Neither of the two suppositions holds in the case of a priest who really intends to celebrate Mass. Hence, though the Greeks may in the best of faith go on erroneously maintaining that they consecrate exclusively in their Epiklesis, they do, nevertheless, as in the case of the Latins, actually consecrate by means of the words of Institution contained in their Liturgies, if Christ has instituted these words as the words of Consecration and the form of the sacrament.
We may in fact go a step farther and assert, that the words of Institution constitute the only and wholly adequate form of the Eucharist and that, consequently, the words of the Epiklesis possess no inherent consecratory value. The contention that the words of the Epiklesis have joint essential value and constitute the partial form of the sacrament, was indeed supported by individual Latin theologians, as Toutée, Renaudot, and Lebrun. Though this opinion cannot be condemned as erroneous in faith, since it allows to the words of Institution their essential, though partial, consecratory value, appears nevertheless to be intrinsically repugnant. For, since the act of Consecration cannot remain, as it were, in a state of suspense, but is completed in an instant of time, there arises the dilemma: Either the words of Institution alone and, therefore, not the Epiklesis, are productive of the conversion, or the words of the Epiklesis alone have such power and not the words of Institution. Of more considerable importance is the circumstance that the whole question came up for discussion in the council for union held at Florence in 1439. Pope Eugene IV urged the Greeks to come to a unanimous agreement with the Roman faith and subscribe to the words of Institution as alone constituting the sacramental form, and to drop the contention that the words of the Epiklesis also possessed a partial consecratory force. But when the Greeks, not without foundation, pleaded that a dogmatic decision would reflect with shame upon their whole ecclesiastical past, the ecumenical synod was satisfied with the oral declaration of Cardinal Bessarion recorded in the minutes of the council for 5 July, 1439 (P. G., CLXI, 491), namely, that the Greeks follow the universal teaching of the Fathers, especially of "blessed John Chrysostom, familiarly known to us", according to whom the "Divine words of Our Redeemer contain the full and entire force of Transubstantiation ".
The venerable antiquity of the Oriental Epiklesis, its peculiar position in the Canon of the Mass, and its interior spiritual unction, oblige the theologian to determine its dogmatic value and to account for its use. Take, for instance, the Epiklesis of the Ethiopian Liturgy : "We implore and beseech Thee, O Lord, to send forth the Holy Spirit and His Power upon this Bread and Chalice and convert them into the Body and Blood of Our Lord Jesus Christ." Since this prayer always follows after the words of Institution have been pronounced, the theological question arises, as to how it may be made to harmonize with the words of Christ, which alone possess the consecrated power. Two explanations have been suggested which, however, can be merged in one. The first view considers the Epiklesis to be a mere declaration of the fact, that the conversion has already taken place, and that in the conversion just as essential a part is to be attributed to the Holy Spirit as Co-Consecrator as in the allied mystery of the Incarnation. Since, however, because of the brevity of the actual instant of conversion, the part taken by the Holy Spirit could not be expressed, the Epiklesis takes us back in imagination to the precious moment and regards the Consecration as just about to occur. A similar purely psychological retrospective transfer is met with in other portions of the Liturgy, as in the Mass for the Dead, wherein the Church prays for the departed as if they were still upon their bed of agony and could still be rescued from the gates of hell. Thus considered, the Epiklesis refers us back to the Consecration as the center about which all the significance contained in its words revolves. A second explanation is based, not upon the enacted Consecration, but upon the approaching Communion, inasmuch as the latter, being the effective means of uniting us more closely in the organized body of the Church, brings forth in our hearts the mystical Christ, as is read in the Roman Canon of the Mass : "Ut nobis corpus et sanguis fiat", i.e. that it may be made for us the body and blood. It was in this purely mystical manner that the Greeks themselves explained the meaning of the Epiklesis at the Council of Florence (Mansi, Collect. Concil., XXXI, 106). Yet since much more is contained in the plain words than this true and deep mysticism, it is desirable to combine both explanations into one, and so we regard the Epiklesis, both in point of liturgy and of time, as the significant connecting link, placed midway between the Consecration and the Communion in order to emphasize the part taken by the Holy Spirit in the Consecration of bread and wine, and, on the other hand, with the help of the same Holy Spirit to obtain the realization of the true Presence of the Body and Blood of Christ by their fruitful effects on both priest and people.
(3) The Effects of the Holy Eucharist
(a) The union with Christ by love
Since the Sacrament of Love is not satisfied with an increase of habitual love only, but tends especially to fan the flame of actual love to an intense ardor, the Holy Eucharist is specifically distinguished from the other sacraments, and hence it is precisely in this latter effect that Francisco Suárez, recognizes the so-called "grace of the sacrament", which otherwise is so hard to discern. It stands to reason that the essence of this union by love consists neither in a natural union with Jesus analogous to that between soul and body, nor in a hypostatic union of the soul with the Person of the Word, nor finally in a pantheistical deification of the communicant, but simply in a moral but wonderful union with Christ by the bond of the most ardent charity. Hence the chief effect of a worthy Communion is to a certain extent a foretaste of heaven, in fact the anticipation and pledge of our future union with God by love in the Beatific Vision. He alone can properly estimate the precious boon which Catholics possess in the Holy Eucharist, who knows how to ponder these ideas of Holy Communion to their utmost depth. The immediate result of this union with Christ by love is the bond of charity existing between the faithful themselves as St. Paul says: "For we being many, are one bread, one body, all that partake of one bread" (1 Corinthians 10:17). And so the Communion of Saints is not merely an ideal union by faith and grace, but an eminently real union, mysteriously constituted, maintained, and guaranteed by partaking in common of one and the same Christ.
(b) The spiritual repast of the soul
Just as food and drink delight and refresh the heart of man, so does this "Heavenly Bread containing within itself all sweetness" produce in the soul of the devout communicant ineffable bliss, which, however, is not to be confounded with an emotional joy of the soul or with sensible sweetness. Although both may occur as the result of a special grace, its true nature is manifested in a certain cheerful and willing fervor in all that regards Christ and His Church, and in the conscious fulfillment of the duties of one's state of life, a disposition of soul which is perfectly compatible with interior desolation and spiritual dryness. A good Communion is recognized less in the transitory sweetness of the emotions than in its lasting practical effects on the conduct of our daily lives.
(c) Forgiveness of venial sin and preservation from mortal sin
(d) The pledge of our resurrection
(4) The Necessity of the Holy Eucharist for Salvation
In the first sense a thing or action is necessary because without it a given end cannot be attained; the eye, e.g. is necessary for vision. The second sort of necessity is that which is imposed by the free will of a superior, e.g. the necessity of fasting. As regards Communion a further distinction must be made between infants and adults. It is easy to prove that in the case of infants Holy Communion is not necessary to salvation, either as a means or as of precept. Since they have not as yet attained to the use of reason, they are free from the obligation of positive laws; consequently, the only question is whether Communion is, like Baptism, necessary for them as a means of salvation. Now the Council of Trent under pain of anathema, solemnly rejects such a necessity (Sess. XXI, can. iv) and declares that the custom of the primitive Church of giving Holy Communion to children was not based upon the erroneous belief of its necessity to salvation, but upon the circumstances of the times (Sess. XXI, cap. iv). Since according to St. Paul's teaching (Romans 8:1) there is "no condemnation" for those who have been baptized, every child that dies in its baptismal innocence, even without Communion, must go straight to heaven. This latter position was that usually taken by the Fathers, with the exception of St. Augustine, who from the universal custom of the Communion of children drew the conclusion of its necessity for salvation.
On the other hand, Communion is prescribed for adults, not only by the law of the Church, but also by a Divine command (John 6:50 sqq.), though for its absolute necessity as a means to salvation there is no more evidence than in the case of infants. For such a necessity could be established only on the supposition that Communion per se constituted a person in the state of grace or that this state could not be preserved without Communion. Neither supposition is correct. Not the first, for the simple reason that the Blessed Eucharist, being a sacrament of the living, presupposes the state of sanctifying grace ; not the second, because in case of necessity, such as might arise, e.g., in a long sea-voyage, the Eucharistic graces may be supplied by actual graces. It is only when viewed in this light that we can understand how the primitive Church, without going counter to the Divine command, withheld the Eucharist from certain sinners even on their deathbeds. There is, however, a moral necessity on the part of adults to receive Holy Communion, as a means, for instance, of overcoming violent temptation, or as a viaticum for persons in danger of death. Eminent divines, like Francisco Suárez, claim that the Eucharist, if not absolutely necessary, is at least a relatively and morally necessary means to salvation, in the sense that no adult can long sustain his spiritual, supernatural life who neglects on principle to approach Holy Communion. This view is supported, not only by the solemn and earnest words of Christ, when He Promised the Eucharist, and by the very nature of the sacrament as the spiritual food and medicine of our souls, but also by the fact of the helplessness and perversity of human nature and by the daily experience of confessors and directors of souls.
Since Christ has left us no definite precept as to the frequency with which He desired us to receive Him in Holy Communion, it belongs to the Church to determine the Divine command more accurately and prescribe what the limits of time shall be for the reception of the sacrament. In the course of centuries the Church's discipline in this respect has undergone considerable change. Whereas the early Christians were accustomed to receive at every celebration of the Liturgy, which probably was not celebrated daily in all places, or were in the habit of Communicating privately in their own homes every day of the week, a falling-off in the frequency of Communion is noticeable since the fourth century. Even in his time Pope Fabian (236-250) made it obligatory to approach the Holy Table three times a year, viz, at Christmas, Easter, and Pentecost, and this custom was still prevalent in the sixth century [cf. Synod of Agde (506), c. xviii]. Although St. Augustine left daily Communion to the free choice of the individual, his admonition, in force even at the present day, was: Sic vive, ut quotidie possis sumere (De dono persev., c. xiv), i e "So live that you may receive every day." From the tenth to the thirteenth century, the practice of going to Communion more frequently during the year was rather rare among the laity and obtained only in cloistered communities. St. Bonaventure reluctantly allowed the lay brothers of his monastery to approach the Holy Table weekly, whereas the rule of the Canons of Chrodegang prescribed this practice. When the Fourth Council of Lateran (1215), held under Innocent III, mitigated the former severity of the Church's law to the extent that all Catholics of both sexes were to communicate at least once a year and this during the paschal season, St. Thomas (III: 80: 10) ascribed this ordinance chiefly to the "reign of impiety and the growing cold of charity". The precept of the yearly paschal Communion was solemnly reiterated by the Council of Trent (Sess. XIII, can. ix). The mystical theologians of the later Middle Ages, as Tauler, St. Vincent Ferrer, Savonarola, and later on St Philip Neri, the Jesuit Order, St. Francis de Sales and St. Alphonsus Liguori were zealous champions of frequent Communion ; whereas the Jansenists, under the leadership of Antoine Arnauld (De la fréquente communion, Paris, 1643), strenuously opposed and demanded as a condition for every Communion the "most perfect penitential dispositions and the purest love of God ". This rigorism was condemned by Pope Alexander VIII (7 Dec., 1690); the Council Trent (Sess. XIII, cap. viii; Sess. XXII, cap. vi) and Innocent XI (12 Feb., 1679) had already emphasized the permissibility of even daily Communion. To root out the last vestiges of Jansenistic rigorism, Pius X issued a decree (24 Dec., 1905) wherein he allows and recommends daily Communion to the entire laity and requires but two conditions for its permissibility, namely, the state of grace and a right and pious intention.
(5) The Minister of the Eucharist
(a) The minister of consecration
(adapted from Catholic Encyclopedia)