not wont to be born save of man and woman: see
therefore that against the established law and order a man is born of
a Virgin": and] [*The passage in the brackets is not in the Leonine
edition] (De Myster. iv): "It is clear that a Virgin begot beyond the
order of nature: and what we make is the body from the Virgin. Why,
then, do you look for nature's order in Christ's body, since the Lord
Jesus was Himself brought forth of a Virgin beyond nature?"
Chrysostom likewise (Hom. xlvii), commenting on John 6:64: "The words
which I have spoken to you," namely, of this sacrament, "are spirit
and life," says: i.e. "spiritual, having nothing carnal, nor natural
consequence; but they are rent from all such necessity which exists
upon earth, and from the laws here established."

For it is evident that every agent acts according as it is in act.
But every created agent is limited in its act, as being of a
determinate genus and species: and consequently the action of every
created agent bears upon some determinate act. Now the determination
of every thing in actual existence comes from its form. Consequently,
no natural or created agent can act except by changing the form in
something; and on this account every change made according to
nature's laws is a formal change. But God is infinite act, as stated
in the First Part (Q. 7, A. 1; Q. 26, A. 2); hence His action extends
to the whole nature of being. Therefore He can work not only formal
conversion, so that diverse forms succeed each other in the same
subject; but also the change of all being, so that, to wit, the whole
substance of one thing be changed into the whole substance of
another. And this is done by Divine power in this sacrament; for the
whole substance of the bread is changed into the whole substance of
Christ's body, and the whole substance of the wine into the whole
substance of Christ's blood. Hence this is not a formal, but a
substantial conversion; nor is it a kind of natural movement: but,
with a name of its own, it can be called "transubstantiation."

Reply Obj. 1: This objection holds good in respect of formal change,
because it belongs to a form to be in matter or in a subject; but it
does not hold good in respect of the change of the entire substance.
Hence, since this substantial change implies a certain order of
substances, one of which is changed into the other, it is in both
substances as in a subject, just as order and number.

Reply Obj. 2: This argum