EXPOSITION OF THE MOST HOLY SACRAMENT. -
Rite by which the consecrated Host is exposed for the adoration of the faithful, either uncovered in the monstrance or enclosed in the ciborium. The origin of exposition does not seem with certainty to go back beyond the 14th century and is connected with the feast of Corpus Christi and especially with the Eucharistic procession of that day. Once the procession had returned to the church, the Most Holy Sacrament, instead of being returned to its tabernacle or repository, was left exposed on the high altar or on a side altar, while Mass was celebrated. An indication of this is found for the city of Minden, in Germany, at the beginning of the 1300s, where the consecrated Host was exposed even during the Office. In the Ordinarium of the church of Strasbourg of 1364, it is prescribed: ponatur Corpus Christi super altare in prima vespera et in matutinis et in Misra. The practice must soon have spread to other places and to other days of the year. Thus, in 1372, Bishop Dietrich of Brandenburg permitted exposition during Mass on the six principal feasts of the year (Christmas, Easter, Pentecost, Corpus Christi, the Dedication of the Church, All Saints). In the 14th century in Germany exposition on Thursday was common, in memory of the institution of the Eucharist. As the practice became widespread in the 15th century in Germany, Holland, and Hungary, abuses and indiscretions easily arose, which the Church immediately sought to remedy, as it did at the Provincial Council of Cologne in 1452, where, under the inspiration of Cardinal Legate Niccolò di Cusa, exposition was forbidden, with the exception of the feast and octave of Corpus Christi, a propter reverentiam divinissimo Eucharistiae sacramento exhibendam et ne populi fidelis devotio ex frequenti eius visione tepescat. Nevertheless, evasions of this precise provision were found: in many places, in fact, exposition was made with the ciborium closed, with the monstrance covered by a veil; elsewhere, Eucharistic shrines, or a kind of monumental tabernacles, were constructed, which through their gridded little door allowed the monstrance or ciborium to be glimpsed. In Italy, France, and Spain exposition spread slowly, until that Quarantore (v.) was reached, in memory of the 40 hours during which, according to s. Agostino, the body of Jesus remained in the tomb.
Exposition, which is always followed by benediction, is distinguished as public and private, according as it is made with the monstrance or with the ciborium. Public exposition is then solemn or most solemn. The former lasts for a certain length of time, whereas the latter is the form proper to the Quarantore. In some churches there is also perpetual exposition by special privilege. Private exposition may take place for a just reason and without the permission of the Ordinary in any church or oratory where the Most Holy Sacrament is reserved, on every day of the year except from the morning of Holy Thursday until the Mass of Holy Saturday, during daylight hours. Public or solemn exposition may be made only for a public cause and with the permission of the Ordinary, with the exception of the feast and octave of Corpus Christi (CIC, can. 1274), for which no permission is required. Its minister is the priest or deacon, but the latter may not give the blessing with the monstrance except in a case of necessity and with the permission of the Ordinary and the parish priest. Exposition may not be made from the morning of Holy Thursday until the Mass of Holy Saturday, nor during the time when the Office is sung or recited in church and the Mass for the dead is celebrated (S. Rit. Congr. Decr. 3479). The monstrance containing the holy Host is placed on the altar beneath the baldachin or on the specially prepared throne. Incense is used as soon as the Sacrament is exposed and at the singing of the Genitori. The celebration of Mass is forbidden at the altar where the Sacrament is exposed. At least 12 candles are required for public exposition. Before the exposed Sacrament, genuflection is made on both knees, and no reverence is made to anyone. Without special permission, it is not lawful to make exposition before dawn or to prolong it beyond the Ave Maria. For the exposition and reposition of the Sacrament, the priest must wear surplice and white stole; for the blessing, the cope and humeral veil are required.