it only being an appearance). They are still the appearances of bread and wine, not of Christ, and do not inhere in the substance of Christ. They can be felt and tasted as before, and are subject to change and can be destroyed. If the appearance of bread is lost by turning to dust or the appearance of wine is lost by turning to vinegar, Christ is no longer present. The essential signs of the Eucharistic sacrament are wheat bread and grape wine, on which the blessing of the Holy Spirit is invoked and the priest pronounces the words of consecration spoken by Jesus during the Last Supper: "This is my body which will be given up for you. ... This is the cup of my blood ..." When the signs cease to exist, so does the sacrament. According to Catholic teaching, the whole of Christ, body and blood, soul and divinity, is really, truly and substantially in the sacrament, under each of the appearances of bread and wine, but he is not in the sacrament as in a place and is not moved when the sacrament is moved. He is perceptible neither by the sense nor by the imagination, but only by the intellectual eye. St. Thomas Aquinas gave poetic expression to this perception in the devotional hymn Adoro te devote: An official statement from the Anglican–Roman Catholic International Commission titled Eucharistic Doctrine, published in 1971, states that "the word transubstantiation is commonly used in the Roman Catholic Church to indicate that God acting in the Eucharist effects a change in the inner reality of the elements. The term should be seen as affirming the fact of Christ's presence and of the mysterious and radical change which takes place. In Roman Catholic theology it is not understood as explaining how the change takes place." In the smallest particle of the host or the smallest droplet from the chalice Jesus Christ himself is present: "Christ is present whole and entire in each of the species and whole and entire in each of their parts, in such a way that the breaking of the bread does not divide Christ." Eastern Christianity As the Disputation of the Holy Sacrament took place in the Western Church after the Great Schism, the Eastern Churches remained largely unaffected by it. The debate on the nature of "transubstantiation" in Greek Orthodoxy begins in the 17th century,