Reply to Objection 4: If before the consecration of the blood, and after the consecration of the body the priest detect that either the wine or the water is absent, then he ought at once to add them and consecrate. But if after the words of consecration he discover that the water is absent, he ought notwithstanding to proceed straight on, because the addition of the water is not necessary for the sacrament, as stated above (Q[74], A[7]): nevertheless the person responsible for the neglect ought to be punished. And on no account should water be mixed with the consecrated wine, because corruption of the sacrament would ensue in part, as was said above (Q[77], A[8]). But if after the words of consecration the priest perceive that no wine has been put in the chalice, and if he detect it before receiving the body, then rejecting the water, he ought to pour in wine with water, and begin over again the consecrating words of the blood. But if he notice it after receiving the body, he ought to procure another host which must be consecrated together with the blood; and I say so for this reason, because if he were to say only the words of consecration of the blood, the proper order of consecrating would not be observed; and, as is laid down by the Council of Toledo, quoted above (ad 1), sacrifices cannot be perfect, except they be performed in perfect order. But if he were to begin from the consecration of the blood, and were to repeat all the words which follow, it would not suffice, unless there was a consecrated host present, since in those words there are things to be said and done not only regarding the blood, but also regarding the body; and at the close he ought once more to receive the consecrated host and blood, even if he had already taken the water which was in the chalice, because the precept of the completing this sacrament is of greater weight than the precept of receiving the sacrament while fasting, as stated above (Q[80], A[8]).
Reply to Objection 5: Although the priest may not recollect having said some of the words he ought to say, he ought not to be disturbed mentally on that account; for a man who utters many words cannot recall to mind all that he has said; unless perchance in uttering them he adverts to something connected with the consecration; for so it is impressed on the memory. Hence, if a man pays attention to what he is saying, but without adverting to the fact that he is saying these particular words, he remembers soon after that he has said them; for, a thing is presented to the memory under the formality of the past (De Mem. et Remin. i).
But if it seem to the priest that he has probably omitted some of the words that are not necessary for the sacrament, I think that he ought not to repeat them on that account, changing the order of the sacrifice, but that he ought to proceed: but if he is certain that he has left out any of those that are necessary for the sacrament, namely, the form of the consecration, since the form of the consecration is necessary for the sacrament, just as the matter is, it seems that the same thing ought to be done as was stated above (ad 4) with regard to defect in the matter, namely, that he should begin again with the form of the consecration, and repeat the other things in order, lest the order of the sacrifice be altered.
Reply to Objection 6: The breaking of the consecrated host, and the putting of only one part into the chalice, regards the mystical body, just as the mixing with water signifies the people, and therefore the omission of either of them causes no such imperfection in the sacrifice, as calls for repetition regarding the celebration of this sacrament.
Reply to Objection 7: According to the decree, De Consecr., dist. ii, quoting a decree of Pope Pius I, "If from neglect any of the blood falls upon a board which is fixed to the ground, let it be taken up with the tongue, and let the board be scraped. But if it be not a board, let the ground be scraped, and the scrapings burned, and the ashes buried inside the altar and let the priest do penance for forty days. But if a drop fall from the chalice on to the altar, let the minister suck up the drop, and do penance during three days; if it falls upon the altar cloth and penetrates to the second altar cloth, let him do four days' penance; if it penetrates to the third, let him do nine days' penance; if to the fourth, let him do twenty days' penance; and let the altar linens which the drop touched be washed three times by the priest, holding the chalice below, then let the water be taken and put away nigh to the altar." It might even be drunk by the minister, unless it might be rejected from nausea. Some persons go further, and cut out that part of the linen, which they burn, putting the ashes in the altar or down the sacrarium. And the Decretal continues with a quotation from the Penitential of Bede the Priest: "If, owing to drunkenness or gluttony, anyone vomits up the Eucharist, let him do forty days' penance, if he be a layman; but let clerics or monks, deacons and priests, do seventy days' penance; and let a bishop do ninety days'. But if they vomit from sickness, let them do penance for seven days." And in the same distinction, we read a decree of the (Fourth) Council of Arles: "They who do not keep proper custody over the sacrament, if a mouse or other animal consume it, must do forty days' penance: he who loses it in a church, or if a part fall and be not found, shall do thirty days' penance." And the priest seems to deserve the same penance, who from neglect allows the hosts to putrefy. And on those days the one doing penance ought to fast, and abstain from Communion. However, after weighing the circumstances of the fact and of the person, the said penances may be lessened or increased. But it must be observed that wherever the species are found to be entire, they must be preserved reverently, or consumed; because Christ's body is there so long as the species last, as stated above (Q[77], AA[4],5). But if it can be done conveniently, the things in which they are found are to be burned, and the ashes put in the sacrarium, as was said of the scrapings of the altar-table, here above.