A third proof might be drawn from the fact that our own bodies exist indeed in themselves, but do not subsist by themselves, as their material nature is taken possession of by a spiritual being—the soul—and subsists by its subsistence. From this fact, which is alluded to in S. Athanasius’ _Symbol_ as an image of the assumption of the human nature by the Word, we might show that suppositality can, even naturally, be supplanted by the union of a lower with a higher nature. But we will not develop this proof, as it requires too long an explanation and many new considerations, which cannot be embodied in the present article. Last, but not least, it is evident that all negations which are not included in the essence of a thing can be supplanted by the position of their contrary. Hence the mode of substance and the mode of suppositum, which are negations, and are not included in the essence of created things, can be supplanted by the intervention of a supernatural power. As we must here keep within the bounds of philosophy, we abstain from discussing other cognate questions which can be safely answered only by a direct appeal to dogmatic definitions and theological arguments. We may, however, state that the old scholastic theologians and the fathers of the church, both Greek and Latin, admitted that the mode of substance, as well as the mode of suppositum, can be made to disappear from the thing to which it naturally belongs in the manner above explained. For their common doctrine on the mysteries of the Incarnation and of the Holy Eucharist is, that the two mysteries are analogous to one another,(19) and admit of a parallel mode of reasoning for their explanation. The analogy more or less explicitly pointed out by them involves the admission of a principle which may be expressed in the following words: “As the whole human nature can exist in Christ _without the mode of human person_, which is excluded by the hypostatic union of the Word with it, so can the whole sensible nature (_species_) of bread exist in the Holy Eucharist _without its mode of substance_, which is excluded by the substantive presence of Christ’s body under it.” This traditional doctrine has been almost ignored in these latter centuries by those who were anxious to explain everything according to a special system of natural philosophy, and who little by little formed a new theory of the sacramental species; but the physical system on which these theologians took their stand having given way, and their new theory having lost its plausibility, we are of opinion that instead of seeking for new explanations, as some do, it is more prudent to fall back on tradition, and take into consideration the authorized teachings of our old polemic writers, of those especially who so valiantly fought against Berengarius and other heretics in behalf of the Eucharistic dogma.