Reply Obj. 3: This corruption of species is not miraculous, but natural; nevertheless, it presupposes the miracle which is wrought in the consecration, namely, that those sacramental species retain without a subject, the same being as they had in a subject; just as a blind man, to whom sight is given miraculously, sees naturally. _______________________
FIFTH ARTICLE [III, Q. 77, Art. 5]
Whether Anything Can Be Generated from the Sacramental Species?
Objection 1: It seems that nothing can be generated from the sacramental species: because, whatever is generated, is generated out of some matter: for nothing is generated out of nothing, although by creation something is made out of nothing. But there is no matter underlying the sacramental species except that of Christ's body, and that body is incorruptible. Therefore it seems that nothing can be generated from the sacramental species.
Obj. 2: Further, things which are not of the same genus cannot spring from one another: thus a line is not made of whiteness. But accident and substance differ generically. Therefore, since the sacramental species are accidents, it seems that no substance can be generated from them.
Obj. 3: Further, if any corporeal substance be generated from them, such substance will not be without accident. Therefore, if any corporeal substance be generated from the sacramental species, then substance and accident would be generated from accident, namely, two things from one, which is impossible. Consequently, it is impossible for any corporeal substance to be generated out of the sacramental species.
On the contrary, The senses are witness that something is generated out of the sacramental species, either ashes, if they be burned, worms if they putrefy, or dust if they be crushed.
I answer that, Since "the corruption of one thing is the generation of another" (De Gener. i), something must be generated necessarily from the sacramental species if they be corrupted, as stated above (A. 4); for they are not corrupted in such a way that they disappear altogether, as if reduced to nothing; on the contrary, something sensible manifestly succeeds to them.
Nevertheless, it is difficult to see how anything can be generated from them. For it is quite evident that nothing is generated out of the body and blood of Christ which are truly there, because these are incorruptible. But if the substance, or even the matter, of the bread and wine were to remain in this sacrament, then, as some have maintained, it would be easy to account for this sensible object which succeeds to them. But that supposition is false, as was stated above (Q. 75, AA. 2, 4, 8).
Hence it is that others have said that the things generated have not sprung from the sacramental species, but from the surrounding atmosphere. But this can be shown in many ways to be impossible. In the first place, because when a thing is generated from another, the latter at first appears changed and corrupted; whereas no alteration or corruption appeared previously in the adjacent atmosphere; hence the worms or ashes are not generated therefrom. Secondly, because the nature of the atmosphere is not such as to permit of such things being generated by such alterations. Thirdly, because it is possible for many consecrated hosts to be burned or putrefied; nor would it be possible for an earthen body, large enough to be generated from the atmosphere, unless a great and, in fact, exceedingly sensible condensation of the atmosphere took place. Fourthly, because the same thing can happen to the solid bodies surrounding them, such as iron or stone, which remain entire after the generation of the aforesaid things. Hence this opinion cannot stand, because it is opposed to what is manifest to our senses.