Transubstantiation (Latin: transubstantiatio; Greek: μετουσίωσις metousiosis) is, according to the teaching of the Catholic Church, "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 the Blood of Christ". 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 this teaching, the notions of "substance" and "transubstantiation" are not linked with any particular theory of metaphysics.