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 pyx. The origin of the e. does not appear to go back with certainty beyond the 14th century and is connected to the feast of Corpus Christi and especially to the eucharistic procession of that day. Once the procession had returned to the church, the Most Blessed Sacrament, instead of being placed back within its tabernacle or repository, was left exposed on the high altar or on a side altar, while Mass followed. 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 Missa. The practice must have spread very quickly to other places and to other days of the year. Thus in 1372 Bishop Dietrich of Brandenburg permitted the e. during Mass on the six principal feasts of the year (Christmas, Easter, Pentecost, Corpus Christi, Dedication of the Church, All Saints). In the 14th century in Germany the e. on Thursdays was common, in memory of the institution of the Eucharist. With the generalization of the practice in the 15th century in Germany, Holland and Hungary, abuses and indiscretions easily arose, which the Church immediately sought to remedy, as it did in the provincial Council of Cologne of 1452, in which, under the inspiration of the cardinal legate Nicholas of Cusa, the e. was forbidden, with the exception of the feast and octave of Corpus Christi, ad propter reverentiam divinissimo Eucharistiae sacramento exibendam et ne populi fidelis devotio ex frequenti eius visione tepescat. Nevertheless, ways were found around this precise regulation: in many places, in fact, the e. was carried out with the pyx closed, with the monstrance covered by a veil; in others eucharistic aedicules were built, or kinds of monumental tabernacles, which through their grated little door allowed the monstrance or pyx to be glimpsed. In Italy, France and Spain the e. penetrated slowly, until it reached that solemn form known as the Forty Hours (v.), in memory of the 40 hours during which, according to St. Augustine, the body of Jesus remained in the tomb.
The e., which is always followed by Benediction, is distinguished into public and private, according as it is done with the monstrance or with the pyx. The public one, moreover, is solemn and most solemn. The first has a certain duration, while the second is that proper to the Forty Hours. In some churches, furthermore, there is perpetual e. by special privilege. The private e. may take place for a just reason and without the permission of the Ordinary in any church or oratory where the Most Blessed Sacrament is kept, on all days of the year, except from the morning of Holy Thursday to the Mass of Holy Saturday, during the daytime hours. The public or solemn e. may be held 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. The minister is the priest or the deacon, but the latter may not give Benediction with the monstrance except in case of necessity and with the permission of the Ordinary and of the parish priest. The e. may not be held from the morning of Holy Thursday to the Mass of Holy Saturday, nor at the time when in church the Office is sung or recited and the Mass of the dead is celebrated (S. Rit. Congr. Decr. 3479). The monstrance containing the holy Host is placed on the altar under the baldachin or on the throne prepared for the purpose. Incense is used as soon as the Sacrament is exposed and at the singing of the Genitori. At the altar where the Sacrament is exposed the celebration of Mass is forbidden. At least 12 candles are required for the public e. Before the exposed Sacrament one genuflects with both knees and no reverence is made to anyone. It is not lawful, without special permission, to hold the e. before dawn or to prolong it beyond the Angelus. For the e. and reposition of the Sacrament the priest must wear a surplice and white stole: for Benediction the cope and the humeral veil are required.