I answer that, After what we have said above (A[1]), it must be held most certainly that the whole Christ is under each sacramental species yet not alike in each. For the body of Christ is indeed present under the species of bread by the power of the sacrament, while the blood is there from real concomitance, as stated above (A[1], ad 1) in regard to the soul and Godhead of Christ; and under the species of wine the blood is present by the power of the sacrament, and His body by real concomitance, as is also His soul and Godhead: because now Christ's blood is not separated from His body, as it was at the time of His Passion and death. Hence if this sacrament had been celebrated then, the body of Christ would have been under the species of the bread, but without the blood; and, under the species of the wine, the blood would have been present without the body, as it was then, in fact.
Reply to Objection 1: Although the whole Christ is under each species, yet it is so not without purpose. For in the first place this serves to represent Christ's Passion, in which the blood was separated from the body; hence in the form for the consecration of the blood mention is made of its shedding. Secondly, it is in keeping with the use of this sacrament, that Christ's body be shown apart to the faithful as food, and the blood as drink. Thirdly, it is in keeping with its effect, in which sense it was stated above (Q[74], A[1]) that "the body is offered for the salvation of the body, and the blood for the salvation of the soul."
Reply to Objection 2: In Christ's Passion, of which this is the memorial, the other parts of the body were not separated from one another, as the blood was, but the body remained entire, according to Ex. 12:46 : "You shall not break a bone thereof." And therefore in this sacrament the blood is consecrated apart from the body, but no other part is consecrated separately from the rest.
Reply to Objection 3: As stated above, the body of Christ is not under the species of wine by the power of the sacrament, but by real concomitance: and therefore by the consecration of the wine the body of Christ is not there of itself, but concomitantly.
Whether Christ is entire under every part of the species of the bread and wine?
Objection 1: It seems that Christ is not entire under every part of the species of bread and wine. Because those species can be divided infinitely. If therefore Christ be entirely under every part of the said species, it would follow that He is in this sacrament an infinite number of times: which is unreasonable; because the infinite is repugnant not only to nature, but likewise to grace.
Objection 2: Further, since Christ's is an organic body, it has parts determinately distant. for a determinate distance of the individual parts from each other is of the very nature of an organic body, as that of eye from eye, and eye from ear. But this could not be so, if Christ were entire under every part of the species; for every part would have to be under every other part, and so where one part would be, there another part would be. It cannot be then that the entire Christ is under every part of the host or of the wine contained in the chalice.
Objection 3: Further, Christ's body always retains the true nature of a body, nor is it ever changed into a spirit. Now it is the nature of a body for it to be "quantity having position" (Predic. iv). But it belongs to the nature of this quantity that the various parts exist in various parts of place. Therefore, apparently it is impossible for the entire Christ to be under every part of the species.
On the contrary, Augustine says in a sermon (Gregory, Sacramentarium): "Each receives Christ the Lord, Who is entire under every morsel, nor is He less in each portion, but bestows Himself entire under each."
I answer that, As was observed above (A[1], ad 3), because the substance of Christ's body is in this sacrament by the power of the sacrament, while dimensive quantity is there by reason of real concomitance, consequently Christ's body is in this sacrament substantively, that is, in the way in which substance is under dimensions, but not after the manner of dimensions, which means, not in the way in which the dimensive quantity of a body is under the dimensive quantity of place.
Now it is evident that the whole nature of a substance is under every part of the dimensions under which it is contained; just as the entire nature of air is under every part of air, and the entire nature of bread under every part of bread; and this indifferently, whether the dimensions be actually divided (as when the air is divided or the bread cut), or whether they be actually undivided, but potentially divisible. And therefore it is manifest that the entire Christ is under every part of the species of the bread, even while the host remains entire, and not merely when it is broken, as some say, giving the example of an image which appears in a mirror, which appears as one in the unbroken mirror, whereas when the mirror is broken, there is an image in each part of the broken mirror: for the comparison is not perfect, because the multiplying of such images results in the broken mirror on account of the various reflections in the various parts of the mirror; but here there is only one consecration, whereby Christ's body is in this sacrament.
Reply to Objection 1: Number follows division, and therefore so long as quantity remains actually undivided, neither is the substance of any thing several times under its proper dimensions, nor is Christ's body several times under the dimensions of the bread; and consequently not an infinite number of times, but just as many times as it is divided into parts.
Reply to Objection 2: The determinate distance of parts in an organic body is based upon its dimensive quantity; but the nature of substance precedes even dimensive quantity. And since the conversion of the substance of the bread is terminated at the substance of the body of Christ, and since according to the manner of substance the body of Christ is properly and directly in this sacrament; such distance of parts is indeed in Christ's true body, which, however, is not compared to this sacrament according to such distance, but according to the manner of its substance, as stated above (A[1], ad 3).
Reply to Objection 3: This argument is based on the nature of a body, arising from dimensive quantity. But it was said above (ad 2) that Christ's body is compared with this sacrament not by reason of dimensive quantity, but by reason of its substance, as already stated.
Whether the whole dimensive quantity of Christ's body is in this sacrament?
Objection 1: It seems that the whole dimensive quantity of Christ's body is not in this sacrament. For it was said (A[3]) that Christ's entire body is contained under every part of the consecrated host. But no dimensive quantity is contained entirely in any whole, and in its every part. Therefore it is impossible for the entire dimensive quantity of Christ's body to be there.
Objection 2: Further, it is impossible for two dimensive quantities to be together, even though one be separate from its subject, and the other in a natural body, as is clear from the Philosopher (Metaph. iii). But the dimensive quantity of the bread remains in this sacrament, as is evident to our senses. Consequently, the dimensive quantity of Christ's body is not there.
Objection 3: Further, if two unequal dimensive quantities be set side by side, the greater will overlap the lesser. But the dimensive quantity of Christ's body is considerably larger than the dimensive quantity of the consecrated host according to every dimension. Therefore, if the dimensive quantity of Christ's body be in this sacrament together with the dimensive quantity of the host, the dimensive quantity of Christ's body is extended beyond the quantity of the host, which nevertheless is not without the substance of Christ's body. Therefore, the substance of Christ's body will be in this sacrament even outside the species of the bread, which is unreasonable, since the substance of Christ's body is in this sacrament, only by the consecration of the bread, as stated above (A[2]). Consequently, it is impossible for the whole dimensive quantity of Christ's body to be in this sacrament.
On the contrary, The existence of the dimensive quantity of any body cannot be separated from the existence of its substance. But in this sacrament the entire substance of Christ's body is present, as stated above (AA[1],3). Therefore the entire dimensive quantity of Christ's body is in this sacrament.
I answer that, As stated above (A[1]), any part of Christ is in this sacrament in two ways: in one way, by the power of the sacrament; in another, from real concomitance. By the power of the sacrament the dimensive quantity of Christ's body is not in this sacrament; for, by the power of the sacrament that is present in this sacrament, whereat the conversion is terminated. But the conversion which takes place in this sacrament is terminated directly at the substance of Christ's body, and not at its dimensions; which is evident from the fact that the dimensive quantity of the bread remains after the consecration, while only the substance of the bread passes away.
Nevertheless, since the substance of Christ's body is not really deprived of its dimensive quantity and its other accidents, hence it comes that by reason of real concomitance the whole dimensive quantity of Christ's body and all its other accidents are in this sacrament.
Reply to Objection 1: The manner of being of every thing is determined by what belongs to it of itself, and not according to what is coupled accidentally with it: thus an object is present to the sight, according as it is white, and not according as it is sweet, although the same object may be both white and sweet; hence sweetness is in the sight after the manner of whiteness, and not after that of sweetness. Since, then, the substance of Christ's body is present on the altar by the power of this sacrament, while its dimensive quantity is there concomitantly and as it were accidentally, therefore the dimensive quantity of Christ's body is in this sacrament, not according to its proper manner (namely, that the whole is in the whole, and the individual parts in individual parts), but after the manner of substance, whose nature is for the whole to be in the whole, and the whole in every part.
Reply to Objection 2: Two dimensive quantities cannot naturally be in the same subject at the same time, so that each be there according to the proper manner of dimensive quantity. But in this sacrament the dimensive quantity of the bread is there after its proper manner, that is, according to commensuration: not so the dimensive quantity of Christ's body, for that is there after the manner of substance, as stated above (ad 1).
Reply to Objection 3: The dimensive quantity of Christ's body is in this sacrament not by way of commensuration, which is proper to quantity, and to which it belongs for the greater to be extended beyond the lesser; but in the way mentioned above (ad 1,2).
Whether Christ's body is in this sacrament as in a place?