At seven o’clock in the evening on August 18, 1996, Fr. Alejandro Pezet was saying Holy Mass at a Catholic church in the commercial center of Buenos Aires. As he was finishing distributing Holy Communion, a woman came up to tell him that she had found a discarded host on a candleholder at the back of the church. On going to the spot indicated, Fr. Alejandro saw the defiled Host. Since he was unable to consume it, he placed it in a container of water and put it away in the tabernacle of the chapel of the Blessed Sacrament.

On Monday, August 26, upon opening the tabernacle, he saw to his amazement that the Host had turned into a bloody substance. He informed Cardinal Jorge Bergoglio, who gave instructions that the Host be professionally photographed. The photos were taken on September 6. They clearly show that the Host, which had become a fragment of bloodied flesh, had grown significantly in size. For several years the Host remained in the tabernacle, the whole affair being kept a strict secret. Since the Host suffered no visible decomposition, Cardinal Bergoglio decided to have it scientifically analyzed.

On October 5, 1999, in the presence of the Cardinal’s representatives, Dr. Castanon took a sample of the bloody fragment and sent it to New York for analysis. Since he did not wish to prejudice the study, he purposely did not inform the team of scientists of its provenance. One of these scientists was Dr. Frederic Zugiba, the well-known cardiologist and forensic pathologist. He determined that the analyzed substance was real flesh and blood containing human DNA. Zugiba testified that, “the analyzed material is a fragment of the heart muscle found in the wall of the left ventricle close to the valves. This muscle is responsible for the contraction of the heart. It should be borne in mind that the left cardiac ventricle pumps blood to all parts of the body. The heart muscle is in an inflammatory condition and contains a large number of white blood cells. This indicates that the heart was alive at the time the sample was taken. It is my contention that the heart was alive, since white blood cells die outside a living organism. They require a living organism to sustain them. Thus, their presence indicates that the heart was alive when the sample was taken. What is more, these white blood cells had penetrated the tissue, which further indicates that the heart had been under severe stress, as if the owner had been beaten severely about the chest.”

Two Australians, journalist Mike Willesee and lawyer Ron Tesoriero, witnessed these tests. Knowing where sample had come from, they were dumbfounded by Dr. Zugiba’s testimony. Mike Willesee asked the scientist how long the white blood cells would have remained alive if they had come from a piece of human tissue, which had been kept in water. They would have ceased to exist in a matter of minutes, Dr. Zugiba replied. The journalist then told the doctor that the source of the sample had first been kept in ordinary water for a month and then for another three years in a container of distilled water; only then had the sample been taken for analysis. Dr. Zugiba’s was at a loss to account for this fact. There was no way of explaining it scientifically, he stated. Only then did Mike Willesee inform Dr. Zugiba that the analyzed sample came from a consecrated Host (white, unleavened bread) that had mysteriously turned into bloody human flesh. Amazed by this information, Dr. Zugiba replied, “How and why a consecrated Host would change its character and become living human flesh and blood will remain an inexplicable mystery to science—a mystery totally beyond her competence.”

Only faith in the extraordinary action of a God provides the reasonable answer—faith in a God, who wants to make us aware that He is truly present in the mystery of the Eucharist.

The Eucharistic miracle in Buenos Aires is an extraordinary sign attested to by science. Through it Jesus desires to arouse in us a lively faith in His real presence in the Eucharist. He reminds us that His presence is real, and not symbolic. Only with the eyes of faith do we see Him under appearance of the consecrated bread and wine. We do not see Him with our bodily eyes, since He is present in His glorified humanity. In the Eucharist Jesus sees and loves us and desires to save us.

In collaboration with Ron Tesoriero, Mike Willesee, one of Australia’s best-known journalists (he converted to Catholicism after working on the documents of another Eucharistic miracle) wrote a book entitled Reason to Believe. In it they present documented facts of Eucharistic miracles and other signs calling people to faith in Christ who abides and teaches in the Catholic Church. They have also made a documentary film on the Eucharist—based largely on the scientific discoveries associated with the miraculous Host in Buenos Aires. Their aim was to give a clear presentation of the Catholic Church’s teaching on the subject of the Eucharist. They screened the film in numerous Australian cities. The showing at Adelaide drew a crowd of two thousand viewers. During the commentary and question period that followed a visibly moved man stood up announcing that he was blind. Having learned that this was an exceptional film, he had very much wanted to see it. Just before the screening, he prayed fervently to Jesus for the grace to see the film. At once his sight was restored to him, but only for the thirty-minute duration of the film. Upon its conclusion, he again lost the ability to see. He confirmed this by describing in minute detail certain scenes of the film. It was an incredible event that moved those present to the core of their being.

Through such wondrous signs God calls souls to conversion. If Jesus causes the Host to become visible flesh and blood, a muscle that is responsible for the contraction of a human heart—a heart that suffers like that of someone who has been beaten severely about the chest, if He does such things, it is in order to arouse and quicken our faith in His real presence in the Eucharist. He thus enables us to see that Holy Mass is a re-presentation (i.e. a making present) of the entire drama of our salvation: Christ’s passion, death, and resurrection. Jesus says to his disciples, “Unless you people see signs and wonders, you will not believe” (Jn 4: 48). There is no need to actively seek out wondrous signs. But if Jesus chooses to give them to us, then it behooves us to accept them with meekness and seek to understand what He desires to tell us by them. Thanks to these signs, many people have discovered faith in God—the One God in the Holy Trinity, who reveals His Son to us: Jesus Christ, who abides in the sacraments and teaches us through Holy Scripture and the Magisterium of the Catholic Church.

 The Eucharist—the actual presence of the risen person of Jesus under the appearances of bread and wine—is one of the most important and most difficult truths revealed to us by Christ. Eucharistic miracles are merely visible confirmations of what He tells us about Himself; namely, that He really does give us His glorified body and blood as spiritual food and drink.

Jesus established the Eucharist on the eve of His passion, death, and resurrection. During the Last Supper, He “took bread, said the blessing, broke it, and giving it to his disciples said, ‘Take and eat; this is my body.’ Then he took a cup, gave thanks,and gave it to them, saying, ‘Drink from it, all of you, for this is my blood of the covenant, which will be shed on behalf of many for the forgiveness of sins’” (Mat 26: 26-28). When Jesus took and gave the apostles the bread and wine, He said, “this is my body….this is my blood” by which He clearly meant that the bread and wine which He gave them to eat and drink really was His body and blood, and not some sort of symbol.

Earlier, in the famous Eucharistic sermon recorded by St. John the Evangelist, Jesus said to the Jews: “Amen, amen, I say to you, unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you. Whoever eats my flesh and drinks my blood has eternal life, and I will raise him on the last day. For my flesh is true food, and my blood is true drink. Whoever eats my flesh and drinks my blood remains in me and I in him” (Jn 6: 53-56). Shocked by Jesus’ words, the Jews said, “How can this man give us his flesh to eat?” (Jn 6: 52). Many of Jesus’ disciples were also scandalized. “This saying is hard,” they objected, “who can accept it?” Knowing that the truth of the Eucharist was a shock and a scandal to many of His listeners, Jesus responded not by retracting His words, but by raising the stakes: “Does this shock you? What if you were to see the Son of Man ascending to where he was before? It is the spirit that gives life, while the flesh is of no avail. The words I have spoken to you are spirit and life”” (Jn 6: 62-63). Here Jesus goes to the heart of the mystery by anticipating the glorification of His humanity through His death, resurrection, and ascension. He will give His flesh and blood as food and drink after the Ascension; that is, when His flesh and blood have been glorified and divinized, for, unglorified, “flesh” is indeed “of no avail.”

Not all Jesus’ listeners accepted His teaching of the Eucharist. Thus He turned to them, saying, “‘But there are some of you who do not believe.’ Jesus knew from the beginning the ones who would not believe and the one who would betray him” (Jn 6: 65). Judas’ betrayal began with his rejection of Jesus’ teaching about His real presence in the Eucharist. In confirmation of this fact, Jesus said, “‘Did I not choose you twelve? Yet is not one of you a devil?’ He was referring to Judas, son of Simon the Iscariot; it was he who would betray him, one of the Twelve” (Jn 6: 70-71).

The Eucharist is the Risen Jesus Himself in His glorified, and thus invisible, humanity. This is the essence of His teaching of the Eucharist (Jn 6: 62-63). By its death and resurrection, the humanity of Jesus takes on a divine nature; it assumes a new order of existence: “For in him dwells the whole fullness of the deity, bodily” (Col 2: 9). In His glorified humanity, the Risen Jesus, becoming omnipresent, gives of Himself in the gift of the Eucharist. He shares with us His resurrected life and love that we may even here on earth experience the reality of heaven and partake of the life of the Holy Trinity.

Confronting the mystery of the Eucharist, human reason feels its impotence and limitations. In his encyclical devoted this sacrament, John Paul II writes: “‘The consecration of the bread and wine effects the change of the whole substance of the bead into the substance of the body of Christ our Lord, and of the whole substance of the wine into the substance of his blood. And the holy Catholic Church has fittingly and properly called this change transubstantiation.’ Truly the Eucharist is a mysterium fidei, a mystery which surpasses our understanding and can only be received in faith, as is often brought out in the catechesis of the Church Fathers regarding this divine sacrament: ‘Do not see—Saint Cyril of Jerusalem exhorts—in the bread and wine merely natural elements, because the Lord has expressly said that they are his body and his blood: faith assures you of this, though your senses suggest otherwise’” (Ecclesia de Eucharistia, 15).

The Eucharist is Christ’s supreme gift and miracle, for in it He gives us Himself and engages us in His work of salvation. He enables us to participate in His victory over death, sin, and Satan, share in the divine nature, and partake of the life of the Holy Trinity. In the Eucharist we receive “the medicine of immortality, the antidote to death” (EE, 18). For this reason, Mother Church holds that every deliberate and freely willed absence from Holy Mass on Sunday is an irretrievable spiritual loss, a sign of loss of faith, and hence a serious sin. Let us also remember that if “a Christian’s conscience is burdened by serious sin, then the path of penance through the sacrament of Reconciliation becomes necessary for full participation in the Eucharistic Sacrifice” (EE, 37).