Article — Wouters, Manual of Moral Theology
Article III. On the Mode of Dispensing the Holy Eucharist
The mode or rite of distributing the Holy Eucharist is set forth in the Roman Missal1 and in the Roman Ritual.2 Specifically, note:
The Most Holy Eucharist is to be given under the species of bread alone (canon 852); from this, as is taught sufficiently commonly, one cannot depart even for giving Viaticum (St. Alphonsus, VI, 245).
A priest of the Latin rite should distribute Communion with unleavened bread; a priest of an Eastern rite, with leavened bread, even to faithful of another rite. But where necessity urges and no priest of a different rite is present, it is permitted for an Eastern priest who uses leavened bread to minister the Eucharist in unleavened bread, and conversely for a Latin or an Eastern priest who uses unleavened bread to minister in leavened bread; but each must preserve his own rite of ministering (canon 851, §§ 1 and 2). Necessity urges sufficiently if on that day the faithful person could not receive Communion without grave inconvenience unless the priest gave him the species of another rite (cf. canon 866, § 1). Therefore it is required that a priest of the other rite be lacking and unable to be approached, and that the present priest be unable to consecrate bread of his own rite.
Sacred vestments and a light must be used, and the prayers assigned in the Ritual must be recited.3 Now it would be a grave sin to omit every sacred vestment. It is venial to use only a stole or only a surplice, or to minister without a light, or to omit the preceding and following prayers. Nevertheless it would be permitted to minister Communion without a sacred vestment and without a light both in a case of necessity and for another truly grave cause, for example if someone sacrilegiously received Viaticum and it must again be carried secretly and clandestinely; likewise in houses where something prevents the inhabitants from suspecting that Communion is being brought (St. Alphonsus, VI, 241).4
Not only one who distributes Communion within Mass, but also one who distributes it immediately before or immediately after, can do this in the vestments of Mass; this also holds of a Mass for the dead.5
The Holy Eucharist must be distributed with the thumb and index finger of the right hand. Nevertheless, it would be permitted to offer it with other fingers if otherwise the people or the dying person would be deprived of Communion. Any just cause does not seem to suffice, since the index finger and thumb are deputed by the rite of the Church for this ministry. But if danger of contagion is feared, the sacred species can be placed in a vessel or in a spoon with a little water, and thus brought to the mouth of the sick person. If the sick person, because of dryness of the mouth, cannot swallow the host, either let the species be given in the mode explained, or after Communion has been taken let a draught of wine or a very small drink of cold, fresh, and, if possible, icy water be given to the sick person (St. Alphonsus, VI, 244, 288).
It is not permitted to give "several Eucharistic forms or particles, nor larger ones, but the customary ones."6 Nevertheless, if a sufficient number of consecrated hosts is lacking, it is permitted to divide small hosts,7 but at most into two or three parts, unless there is a special reason for dividing even into more parts, for example if the priest rarely comes somewhere. Likewise, if someone otherwise would have to wait too long, it is permitted to remove a particle from the host of the Mass (St. Alphonsus, VI, 245).
1 Order for Celebrating Mass, title X, n. 6.
2 Title IV, chapter 2.
3 The Sacred Congregation for the Discipline of the Sacraments, 16 March 1929 (Acta Apostolicae Sedis 1929, p. 638), prescribed that besides the linen cloth extended before those communicating, a paten made of silver or gilded metal is to be used.
4 Cf. Sacred Congregation of Propaganda Fide, 9 December 1822 (Collectanea, n. 778).
5 S.R.C., 19 December 1829, n. 2672, ad 2; 23 July 1868, n. 3177.
6 Decree of Innocent XI, 12 February 1679.
7 S.R.C., 16 March 1833, n. 2704, ad 1.