"what looks and tastes like bread and wine is . . . the body and blood of Christ"

Basilica of the National Shrine

     "[1] . . . Since Christ himself has declared the bread to be his body, who can have any further doubt? Since he himself has said quite categorically [(αὐτοῦ βεβαιωσαμένου)], This is my blood, who would dare to question it and say that it is not his blood? . . .
     "[3] Therefore, it is with complete assurance [(μετὰ πάσης πληροφορίας)] that we receive the bread and wine as the body and blood of Christ. His body is given to us under the symbol of bread [(ἐν τύπῳ ἂρτου)], and his blood is given to us under the symbol of wine [(ἐν τύπῳ οἴνου)], in order to make us by receiving them one body and blood with him. Having his body and blood in our members, we become bearers of Christ [(Χριστοφόροι, Christophers)] and sharers, as Saint Peter says, in the divine nature. . . .
     "[7] May purity of conscience remove the veil from the face of your soul so that by contemplating the glory of the Lord, as in a mirror [(κατοπτιζόμενον, as in 2 Cor 3:18)], you may be transformed from glory to glory in Christ Jesus our Lord. To him be glory for ever and ever. Amen."

     St. Cyril of Jerusalem, Mystical catechesis 4.1, 3, and 9, with the original Greek taken from PG 33, cols. 1097A, 1100A, and 1104C, i.e. not yet Sources Chrétiennes or any of the other 20th-century editions.
     I haven't yet read the whole of this, but note that in 4.2, at least (which the Liturgy of the hours passes over), there is, with reference to the miracle at Cana, and therefore by implication the eucharistic elements, the language of transmutation (μεταβέβληκεν, μεταβαλὼν).  The headline I have taken from 4.9.  Cf. 4.6:  "Do not, then, regard the eucharistic elements as ordinary bread and wine; they are . . . the body and blood of the Lord, as he himself has declared."
     Re. that last paragraph, are we then contemplating, as in a mirror, "his body and blood in our members"?