Reservation of the Blessed Sacrament, the practice of preserving after the celebration of the Liturgy a portion of the consecrated elements for the Communion of the sick or for other pious purposes. The extreme antiquity of such reservation cannot be disputed. Already Justin Martyr, in the first detailed account of Eucharistic practice we possess, tells us that at the close of the Liturgy “there is a distribution to each and a participation of that over which thanks have been given, and to those who are absent a portion is sent by the deacons” (I Apol., lxxxvii). Again St. Irenaeus as quoted by Eusebius (Hist. eccl., V, xxiv, 15) wrote to Pope Victor that “the presbyters before thee who did not observe it [i.e., the Quartodeciman practice] sent the Eucharist to those of other districts who did observe it”. Tertullian uses the actual word, reservare, and seems to suggest that a man who scrupled to break his fast on a fast day might approach the Holy Table and carry the Blessed Sacrament away with him to consume it later on—”accepto corpore Domini et reservato, utrumque salvum eat, et participatio sacramenti et executio officii” (“De orat.”, XIX; C. S. E. L., XX, 192. Cf. “Ad ux.”, II, 5).
In St. Cyprian, about the middle of the third century, we already find the record of Eucharistic miracles, as, for example, when he tells us of a woman who sought to open with polluted hands the casket (arcs) in which she kept the Blessed Sacrament and was deterred by flames bursting from it (De lapsis, 26; C. S. E. L., I, 256). And again, at about the same period, an account written by St. Dionysius of Alexandria has been copied by Eusebius (Hist. eccl., VI xliv) from which we learn that a priest, being ill and unable himself to visit a dying person who had sent a boy to him to ask for the Holy Viaticum in the middle of the night, gave the boy a portion of the Eucharist to take to the sufferer who was to consume it moistened with water. This story illustrates the first and primary purpose of reservation, which is thus formally stated in the thirteenth canon of Nicia: “With respect to the dying, the old rule of the Church should continue to be observed which forbids that anyone who is on the point of death should be deprived of the last and most necessary Viaticum” (Greek: tou teleutaiou kai anagkaiotatou ephodiou). But it was clearly also permitted to Christians, especially in the time of persecution, to keep the Blessed Sacrament in their own possession that they might receive it privately (see, e.g., St. Basil, Ep. cclxxxix, “Ad Caesar”, and St. Jerome, Ep. i, “Ad Pammach.”, n. 15). This usage lasted on for many centuries, especially under certain exceptional circumstances, for example, in the case of hermits. An answer given by the Bishop of Corinth to Luke the Younger, an anchoret in Achaia in the tenth century, explains in detail how Communion should be received under such circumstances (Combefis, “Patr. Bib. Auctuar.”, II, 45).
At an earlier date, when certain heretically-minded monks of Mount Calamon in Palestine expressed doubts whether the Holy Eucharist which had been kept to the morrow did not lose its consecration, St. Cyril of Alexandria wrote (P.G., LXXVI, 1075) that those who so spoke must be mad (ii Lrorr e). What is more surprising, it remained the custom in many religious houses of women in the West down to the eleventh and twelfth centuries or later to receive on the day of their solemn profession a little provision of the Blessed Sacrament, and with this they spent a period of eight days in a sort of retreat, being free “to partake daily of this heavenly food” (see Marten, “De Antiquis Ecclesiae Ritibus”, II, 187). We also learn that Christians sought to carry the Blessed Sacrament about with them in times of grievous peril as a means of protection (St. Ambrose, “De Excessu Fratris”, I, 43) or as a source of consolation. Further, as noticed above, the Eucharist was sent from one bishop to another in token of charitable communion, and it appears from the first “Ordo Romanus” (nn. 8 and 22) that a portion of the Eucharist remaining over from a previous sacrifice was mingled with the elements consecrated in the next celebration, probably as a token of continuity, while the practice of the Mass of the Presanctified, in which the species previously consecrated alone were used, was from an early period prescribed in the Eastern Church through-out the whole of Lent, the Sundays only excepted.
On the other hand, there appears to be no reliable evidence that before the year 1000, or even later, the Blessed Sacrament was kept in churches in order that the faithful might visit it or pray before it. Such evidence as has been quoted in proof of such a practice will be found on closer inspection to tell the other way. For example, though the altar is called by St. Optatus of Milevis (“De schism. Don.”, VI, I; in P.L., XI, 1066) the throne of the Body and Blood of Christ (sedes et corporis et sanguinis Christi), the altar is also described in the same context as the place “where Christ’s Body and Blood dwell for a certain brief space” (per certa momenta). Further, the true explanation of a passage in which St. Gregory Nazianzen describes his sister Gorgonia as visiting the altar in the middle of the night (P.G., XXXV, 810) seems to be that she went there to seek such crumbs or traces of the Eucharistic species as might accidentally have fallen and been overlooked (see Journal of Theol. Stud., January, 1910, pp. 275-78). It would probably, then, be correct to say that down to the later Middle Ages, those who came to the church to pray outside the hours of service came there not so much to honor the Eucharistic presence as to pray before the altar upon which Jesus Christ was wont to descend when the words of consecration were spoken in the Mass.
As to the manner and place of reservation during the early centuries there was no great uniformity of practice. Undoubtedly the Eucharist was at first often kept in private houses, but a Council of Toledo in 480, which denounced those who did not immediately consume the sacred species when they received them from the priest at the altar, very possibly marks a change in this regard. On the other hand numerous decrees of synods and penalties entered in penitential books impose upon parish priests the duty of reserving the Blessed Sacrament for the use of the sick and dying, and at the same time of keeping it reverently and securely while providing by frequent renewal against any danger of the corruption of the sacred species. Caskets In the form of a dove or of a tower, made for the most part of one of the precious metals, were commonly used for the purpose, but whether in the early Middle Ages these Eucharistic vessels were kept over the altar, or elsewhere in the church, or in the sacristy, does not clearly appear. After the tenth century the commonest usage in England and France seems to have been to suspend the Blessed Sacrament in a dove-shaped vessel by a cord over the high altar; but fixed and locked tabernacles were also known and indeed prescribed by the regulations of Bishop Quivil of Exeter at the end of the thirteenth century, though in England they never came into general use before the Reformation. In Germany, in the fourteenth and fifteenth centuries, a custom widely prevailed of enshrining the Eucharist in a “sacrament house”, often beautifully decorated, separate from the high altar, but only a short distance away from it, and on the north, or Gospel, side of the Church. This custom seems to have originated in the desire to allow the Blessed Sacrament to be seen by the faithful without exactly contravening the synodal decrees which forbade any continuous exposition. In the sacrament house the door was invariably made of metal lattice work, through which the vessel containing the sacred species could be discerned at least obscurely.
In modern times many provisions have been made to ensure reverence and security in the reservation of the Blessed Sacrament. With regard to the renewal of the species, it is laid down that the Eucharist should not be left for longer than a month, while a much less interval is recommended and generally followed in practice. The practice of burning a light before the tabernacle or other receptacle dates from the thirteenth century or earlier, but it was not at first regarded as of strict obligation. In the Greek Church the consecrated loaf is moistened with the species of wine and kept as a sort of crumbling paste.