283. What is the meaning of transubstantiation?

283. What is the meaning of transubstantiation?    

(Comp 283) Transubstantiation means the change of the whole substance of bread into the substance of the Body of Christ and of the whole substance of wine into the substance of his Blood. This change is brought about in the eucharistic prayer through the efficacy of the word of Christ and by the action of the Holy Spirit. However, the outward characteristics of bread and wine, that is the “eucharistic species”, remain unaltered.

“In brief”  

(CCC 1413) By the consecration the transubstantiation of the bread and wine into the Body and Blood of Christ is brought about. Under the consecrated species of bread and wine Christ himself, living and glorious, is present in a true, real, and substantial manner: his Body and his Blood, with his soul and his divinity (cf. Council of Trent: DS 1640; 1651). 

To deepen and explain  

(CCC 1376) The Council of Trent summarizes the Catholic faith by declaring: "Because Christ our Redeemer said that it was truly his body that he was offering under the species of bread, it has always been the conviction of the Church of God, and this holy Council now declares again, that by the consecration of the bread and wine there takes place a change of the whole substance of the bread into the substance of the body of Christ our Lord and of the whole substance of the wine into the substance of his blood. This change the holy Catholic Church has fittingly and properly called transubstantiation" (Council of Trent (1551): DS 1642; cf. Mt 26:26 ff.; Mk 14:22 ff.; Lk 22:19 ff.; 1 Cor 11:24 ff).

On reflection  

(CCC 1418) Because Christ himself is present in the sacrament of the altar, he is to be honored with the worship of adoration. "To visit the Blessed Sacrament is… a proof of gratitude, an expression of love, and a duty of adoration toward Christ our Lord" (Paul VI, MF 66). 

(Next question: Does the breaking of the bread divide Christ?)