Council of Trent:
“And this faith has ever been in the Church of God, that, immediately after the consecration, the veritable Body of our Lord, and His veritable Blood, together with His Soul and Divinity, are under the species of bread and wine; but the Body indeed under the species of bread, and the Blood under the species of wine, by the force of the words; but the Body itself under the species of wine, and the Blood under the species of bread, and the Soul under both, by the force of that natural connection and concomitancy whereby the parts of Christ our Lord, who has now risen from the dead to die no more, are united together; and the Divinity, furthermore, on account of the admirable hypostatic union thereof with His Body and Soul. Therefore it is most true, that as much is contained under either species as under both; for Christ whole and entire is under the species of bread, and under any part whatsoever of that species; likewise the whole is under the species of wine, and under the parts thereof.”
My understanding of this dogma is that the substance of bread changes only into the substance of Christ’s body, then the rest of His human nature (blood, soul) becomes present by the connection and concomitancy of all the parts of His human nature, and His Divinity becomes present by the hypostatic union of the two natures. But all this occurs in one and the same instant, not successively.
The same applies to the wine, except that the substance of wine is changed into the substance of blood.
The substances of the bread and the wine do change into Christ’s soul. And no mere created thing can be changed into the Divine Nature. So the substances of bread and wine are not changed into all of Christ, though all of Christ is immediately present.