Section — Prümmer, Manuale Theologiae Moralis
§ 5. On The Application Of Form To Matter
19. 1. Ordinarily, the application of form to matter must be made by one and the same minister. For the administration of the sacraments is one action to be performed in the name of Christ, which is composed of two elements, namely, the application of form to matter. But if one person were to apply the matter and another the form, two actions rather than one would be completed. Moreover, the signification of the form would often not be verified if one person were to apply the remote matter and another pronounce the form; for example, the form of baptism would be false if one person poured water over the one to be baptized and another said: "I baptize you, etc."55
I said, however, ordinarily. For in the sacrament of penance the penitent applies the matter, namely, by placing the acts of contrition, confession, and satisfaction; but the confessor applies the form by pronouncing absolution. Moreover, it can happen that several persons consecrate the Eucharist together, as occurs in the ordination of a priest, and more often in the Greek Church. In extreme unction also the individual anointings can be made by different persons, as will be said below in the treatise on extreme unction.
55 Cf. S. theol. 3, q. 67, a. 6.
20. 2. The form must be applied vocally and without interruption.
a) Since the form is part of the sensible sign in the sacraments and consists in words, it must necessarily be expressed vocally. Hence it is required that the minister hear himself, or at least be able to hear himself, while pronouncing the form. It is not sufficient merely to express the words of the form mentally. In practice, the essential words of the form are to be pronounced more clearly and slowly than, for example, in the private recitation of the Breviary. For the validity of the sacrament of matrimony, however, it is indeed sufficient that consent be manifested by each party through any external sign whatsoever. Nevertheless, ordinarily it must be insisted that those entering marriage express consent orally and clearly. (More fully on this matter in the treatise on matrimony.)
b) The words of the form must be pronounced in one continuous course and without interruption.
The reason is that otherwise they easily lose their signification. Therefore, if the interruption is so great that the words no longer effect one complete sense, the sacrament is invalid.56 Yet in practice the nullity of a sacrament on account of an interruption of the form can with difficulty be determined with certainty. Casuists rightly note, however, that the sense of the form is lost much more easily if not only words but also syllables are separated. Thus, for example, they say: If one baptizing, after saying "I baptize you," were to exclaim toward the sacristan, "Hold the basin thus," or if he were to sneeze, cough moderately, or spit, and then continue, "in the name of the Father and of the Son and of the Holy Spirit," the baptism would have been validly conferred. Or if the confessor, after saying "I absolve you," noticed that the penitent had departed from the confessional, recalled him by exclaiming, "What is this? Why did you not wait? Return and kneel," and only then added, "from your sins," he validly absolves. On the contrary, they say that the consecration would be invalid if the priest, after saying "For this is My Bo-" were to cough notably and then continue, "-dy."57 All these or similar casuistic resolutions are of little usefulness for practice, in which the following are to be observed:
Every interruption of the form is diligently and, so far as possible, to be avoided. Hence priests who utter interjections during the pronouncement of the form act truly scandalously.
When some involuntary interruption occurs during the pronouncement of the form, for example, by sneezing or coughing, then the form is to be pronounced anew, unless it is certain that the essential part of the form has already been pronounced. Thus, for example, if a priest coughs or sneezes while pronouncing the words "For this is My Body," he does much better if, after the coughing or sneezing has ended, he begins again: "For this is, etc." On the contrary, if he coughs or sneezes after he has said "For this is the chalice of My Blood, of the new and eternal testament," he ought not, after the coughing or sneezing has ended, to begin the form again, but to continue it.
56 L.c., q. 68, a. 8 ad 3.
57 Cf. Noldin, De sacr., n. 16.